Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2219 insertions, 0 deletions

diff --git a/drivers/scsi/cxlflash/superpipe.c b/drivers/scsi/cxlflash/superpipe.c
new file mode 100644
index 000000000..5dddf67df
--- /dev/null
+++ b/drivers/scsi/cxlflash/superpipe.c
@@ -0,0 +1,2219 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * CXL Flash Device Driver
+ *
+ * Written by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>, IBM Corporation
+ *             Matthew R. Ochs <mrochs@linux.vnet.ibm.com>, IBM Corporation
+ *
+ * Copyright (C) 2015 IBM Corporation
+ */
+
+#include <linux/delay.h>
+#include <linux/file.h>
+#include <linux/interrupt.h>
+#include <linux/pci.h>
+#include <linux/syscalls.h>
+#include <asm/unaligned.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_eh.h>
+#include <uapi/scsi/cxlflash_ioctl.h>
+
+#include "sislite.h"
+#include "common.h"
+#include "vlun.h"
+#include "superpipe.h"
+
+struct cxlflash_global global;
+
+/**
+ * marshal_rele_to_resize() - translate release to resize structure
+ * @rele:	Source structure from which to translate/copy.
+ * @resize:	Destination structure for the translate/copy.
+ */
+static void marshal_rele_to_resize(struct dk_cxlflash_release *release,
+				   struct dk_cxlflash_resize *resize)
+{
+	resize->hdr = release->hdr;
+	resize->context_id = release->context_id;
+	resize->rsrc_handle = release->rsrc_handle;
+}
+
+/**
+ * marshal_det_to_rele() - translate detach to release structure
+ * @detach:	Destination structure for the translate/copy.
+ * @rele:	Source structure from which to translate/copy.
+ */
+static void marshal_det_to_rele(struct dk_cxlflash_detach *detach,
+				struct dk_cxlflash_release *release)
+{
+	release->hdr = detach->hdr;
+	release->context_id = detach->context_id;
+}
+
+/**
+ * marshal_udir_to_rele() - translate udirect to release structure
+ * @udirect:	Source structure from which to translate/copy.
+ * @release:	Destination structure for the translate/copy.
+ */
+static void marshal_udir_to_rele(struct dk_cxlflash_udirect *udirect,
+				 struct dk_cxlflash_release *release)
+{
+	release->hdr = udirect->hdr;
+	release->context_id = udirect->context_id;
+	release->rsrc_handle = udirect->rsrc_handle;
+}
+
+/**
+ * cxlflash_free_errpage() - frees resources associated with global error page
+ */
+void cxlflash_free_errpage(void)
+{
+
+	mutex_lock(&global.mutex);
+	if (global.err_page) {
+		__free_page(global.err_page);
+		global.err_page = NULL;
+	}
+	mutex_unlock(&global.mutex);
+}
+
+/**
+ * cxlflash_stop_term_user_contexts() - stops/terminates known user contexts
+ * @cfg:	Internal structure associated with the host.
+ *
+ * When the host needs to go down, all users must be quiesced and their
+ * memory freed. This is accomplished by putting the contexts in error
+ * state which will notify the user and let them 'drive' the tear down.
+ * Meanwhile, this routine camps until all user contexts have been removed.
+ *
+ * Note that the main loop in this routine will always execute at least once
+ * to flush the reset_waitq.
+ */
+void cxlflash_stop_term_user_contexts(struct cxlflash_cfg *cfg)
+{
+	struct device *dev = &cfg->dev->dev;
+	int i, found = true;
+
+	cxlflash_mark_contexts_error(cfg);
+
+	while (true) {
+		for (i = 0; i < MAX_CONTEXT; i++)
+			if (cfg->ctx_tbl[i]) {
+				found = true;
+				break;
+			}
+
+		if (!found && list_empty(&cfg->ctx_err_recovery))
+			return;
+
+		dev_dbg(dev, "%s: Wait for user contexts to quiesce...\n",
+			__func__);
+		wake_up_all(&cfg->reset_waitq);
+		ssleep(1);
+		found = false;
+	}
+}
+
+/**
+ * find_error_context() - locates a context by cookie on the error recovery list
+ * @cfg:	Internal structure associated with the host.
+ * @rctxid:	Desired context by id.
+ * @file:	Desired context by file.
+ *
+ * Return: Found context on success, NULL on failure
+ */
+static struct ctx_info *find_error_context(struct cxlflash_cfg *cfg, u64 rctxid,
+					   struct file *file)
+{
+	struct ctx_info *ctxi;
+
+	list_for_each_entry(ctxi, &cfg->ctx_err_recovery, list)
+		if ((ctxi->ctxid == rctxid) || (ctxi->file == file))
+			return ctxi;
+
+	return NULL;
+}
+
+/**
+ * get_context() - obtains a validated and locked context reference
+ * @cfg:	Internal structure associated with the host.
+ * @rctxid:	Desired context (raw, un-decoded format).
+ * @arg:	LUN information or file associated with request.
+ * @ctx_ctrl:	Control information to 'steer' desired lookup.
+ *
+ * NOTE: despite the name pid, in linux, current->pid actually refers
+ * to the lightweight process id (tid) and can change if the process is
+ * multi threaded. The tgid remains constant for the process and only changes
+ * when the process of fork. For all intents and purposes, think of tgid
+ * as a pid in the traditional sense.
+ *
+ * Return: Validated context on success, NULL on failure
+ */
+struct ctx_info *get_context(struct cxlflash_cfg *cfg, u64 rctxid,
+			     void *arg, enum ctx_ctrl ctx_ctrl)
+{
+	struct device *dev = &cfg->dev->dev;
+	struct ctx_info *ctxi = NULL;
+	struct lun_access *lun_access = NULL;
+	struct file *file = NULL;
+	struct llun_info *lli = arg;
+	u64 ctxid = DECODE_CTXID(rctxid);
+	int rc;
+	pid_t pid = task_tgid_nr(current), ctxpid = 0;
+
+	if (ctx_ctrl & CTX_CTRL_FILE) {
+		lli = NULL;
+		file = (struct file *)arg;
+	}
+
+	if (ctx_ctrl & CTX_CTRL_CLONE)
+		pid = task_ppid_nr(current);
+
+	if (likely(ctxid < MAX_CONTEXT)) {
+		while (true) {
+			mutex_lock(&cfg->ctx_tbl_list_mutex);
+			ctxi = cfg->ctx_tbl[ctxid];
+			if (ctxi)
+				if ((file && (ctxi->file != file)) ||
+				    (!file && (ctxi->ctxid != rctxid)))
+					ctxi = NULL;
+
+			if ((ctx_ctrl & CTX_CTRL_ERR) ||
+			    (!ctxi && (ctx_ctrl & CTX_CTRL_ERR_FALLBACK)))
+				ctxi = find_error_context(cfg, rctxid, file);
+			if (!ctxi) {
+				mutex_unlock(&cfg->ctx_tbl_list_mutex);
+				goto out;
+			}
+
+			/*
+			 * Need to acquire ownership of the context while still
+			 * under the table/list lock to serialize with a remove
+			 * thread. Use the 'try' to avoid stalling the
+			 * table/list lock for a single context.
+			 *
+			 * Note that the lock order is:
+			 *
+			 *	cfg->ctx_tbl_list_mutex -> ctxi->mutex
+			 *
+			 * Therefore release ctx_tbl_list_mutex before retrying.
+			 */
+			rc = mutex_trylock(&ctxi->mutex);
+			mutex_unlock(&cfg->ctx_tbl_list_mutex);
+			if (rc)
+				break; /* got the context's lock! */
+		}
+
+		if (ctxi->unavail)
+			goto denied;
+
+		ctxpid = ctxi->pid;
+		if (likely(!(ctx_ctrl & CTX_CTRL_NOPID)))
+			if (pid != ctxpid)
+				goto denied;
+
+		if (lli) {
+			list_for_each_entry(lun_access, &ctxi->luns, list)
+				if (lun_access->lli == lli)
+					goto out;
+			goto denied;
+		}
+	}
+
+out:
+	dev_dbg(dev, "%s: rctxid=%016llx ctxinfo=%p ctxpid=%u pid=%u "
+		"ctx_ctrl=%u\n", __func__, rctxid, ctxi, ctxpid, pid,
+		ctx_ctrl);
+
+	return ctxi;
+
+denied:
+	mutex_unlock(&ctxi->mutex);
+	ctxi = NULL;
+	goto out;
+}
+
+/**
+ * put_context() - release a context that was retrieved from get_context()
+ * @ctxi:	Context to release.
+ *
+ * For now, releasing the context equates to unlocking it's mutex.
+ */
+void put_context(struct ctx_info *ctxi)
+{
+	mutex_unlock(&ctxi->mutex);
+}
+
+/**
+ * afu_attach() - attach a context to the AFU
+ * @cfg:	Internal structure associated with the host.
+ * @ctxi:	Context to attach.
+ *
+ * Upon setting the context capabilities, they must be confirmed with
+ * a read back operation as the context might have been closed since
+ * the mailbox was unlocked. When this occurs, registration is failed.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int afu_attach(struct cxlflash_cfg *cfg, struct ctx_info *ctxi)
+{
+	struct device *dev = &cfg->dev->dev;
+	struct afu *afu = cfg->afu;
+	struct sisl_ctrl_map __iomem *ctrl_map = ctxi->ctrl_map;
+	int rc = 0;
+	struct hwq *hwq = get_hwq(afu, PRIMARY_HWQ);
+	u64 val;
+	int i;
+
+	/* Unlock cap and restrict user to read/write cmds in translated mode */
+	readq_be(&ctrl_map->mbox_r);
+	val = (SISL_CTX_CAP_READ_CMD | SISL_CTX_CAP_WRITE_CMD);
+	writeq_be(val, &ctrl_map->ctx_cap);
+	val = readq_be(&ctrl_map->ctx_cap);
+	if (val != (SISL_CTX_CAP_READ_CMD | SISL_CTX_CAP_WRITE_CMD)) {
+		dev_err(dev, "%s: ctx may be closed val=%016llx\n",
+			__func__, val);
+		rc = -EAGAIN;
+		goto out;
+	}
+
+	if (afu_is_ocxl_lisn(afu)) {
+		/* Set up the LISN effective address for each interrupt */
+		for (i = 0; i < ctxi->irqs; i++) {
+			val = cfg->ops->get_irq_objhndl(ctxi->ctx, i);
+			writeq_be(val, &ctrl_map->lisn_ea[i]);
+		}
+
+		/* Use primary HWQ PASID as identifier for all interrupts */
+		val = hwq->ctx_hndl;
+		writeq_be(SISL_LISN_PASID(val, val), &ctrl_map->lisn_pasid[0]);
+		writeq_be(SISL_LISN_PASID(0UL, val), &ctrl_map->lisn_pasid[1]);
+	}
+
+	/* Set up MMIO registers pointing to the RHT */
+	writeq_be((u64)ctxi->rht_start, &ctrl_map->rht_start);
+	val = SISL_RHT_CNT_ID((u64)MAX_RHT_PER_CONTEXT, (u64)(hwq->ctx_hndl));
+	writeq_be(val, &ctrl_map->rht_cnt_id);
+out:
+	dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
+	return rc;
+}
+
+/**
+ * read_cap16() - issues a SCSI READ_CAP16 command
+ * @sdev:	SCSI device associated with LUN.
+ * @lli:	LUN destined for capacity request.
+ *
+ * The READ_CAP16 can take quite a while to complete. Should an EEH occur while
+ * in scsi_execute(), the EEH handler will attempt to recover. As part of the
+ * recovery, the handler drains all currently running ioctls, waiting until they
+ * have completed before proceeding with a reset. As this routine is used on the
+ * ioctl path, this can create a condition where the EEH handler becomes stuck,
+ * infinitely waiting for this ioctl thread. To avoid this behavior, temporarily
+ * unmark this thread as an ioctl thread by releasing the ioctl read semaphore.
+ * This will allow the EEH handler to proceed with a recovery while this thread
+ * is still running. Once the scsi_execute() returns, reacquire the ioctl read
+ * semaphore and check the adapter state in case it changed while inside of
+ * scsi_execute(). The state check will wait if the adapter is still being
+ * recovered or return a failure if the recovery failed. In the event that the
+ * adapter reset failed, simply return the failure as the ioctl would be unable
+ * to continue.
+ *
+ * Note that the above puts a requirement on this routine to only be called on
+ * an ioctl thread.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int read_cap16(struct scsi_device *sdev, struct llun_info *lli)
+{
+	struct cxlflash_cfg *cfg = shost_priv(sdev->host);
+	struct device *dev = &cfg->dev->dev;
+	struct glun_info *gli = lli->parent;
+	struct scsi_sense_hdr sshdr;
+	u8 *cmd_buf = NULL;
+	u8 *scsi_cmd = NULL;
+	int rc = 0;
+	int result = 0;
+	int retry_cnt = 0;
+	u32 to = CMD_TIMEOUT * HZ;
+
+retry:
+	cmd_buf = kzalloc(CMD_BUFSIZE, GFP_KERNEL);
+	scsi_cmd = kzalloc(MAX_COMMAND_SIZE, GFP_KERNEL);
+	if (unlikely(!cmd_buf || !scsi_cmd)) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	scsi_cmd[0] = SERVICE_ACTION_IN_16;	/* read cap(16) */
+	scsi_cmd[1] = SAI_READ_CAPACITY_16;	/* service action */
+	put_unaligned_be32(CMD_BUFSIZE, &scsi_cmd[10]);
+
+	dev_dbg(dev, "%s: %ssending cmd(%02x)\n", __func__,
+		retry_cnt ? "re" : "", scsi_cmd[0]);
+
+	/* Drop the ioctl read semahpore across lengthy call */
+	up_read(&cfg->ioctl_rwsem);
+	result = scsi_execute(sdev, scsi_cmd, DMA_FROM_DEVICE, cmd_buf,
+			      CMD_BUFSIZE, NULL, &sshdr, to, CMD_RETRIES,
+			      0, 0, NULL);
+	down_read(&cfg->ioctl_rwsem);
+	rc = check_state(cfg);
+	if (rc) {
+		dev_err(dev, "%s: Failed state result=%08x\n",
+			__func__, result);
+		rc = -ENODEV;
+		goto out;
+	}
+
+	if (driver_byte(result) == DRIVER_SENSE) {
+		result &= ~(0xFF<<24); /* DRIVER_SENSE is not an error */
+		if (result & SAM_STAT_CHECK_CONDITION) {
+			switch (sshdr.sense_key) {
+			case NO_SENSE:
+			case RECOVERED_ERROR:
+			case NOT_READY:
+				result &= ~SAM_STAT_CHECK_CONDITION;
+				break;
+			case UNIT_ATTENTION:
+				switch (sshdr.asc) {
+				case 0x29: /* Power on Reset or Device Reset */
+					fallthrough;
+				case 0x2A: /* Device capacity changed */
+				case 0x3F: /* Report LUNs changed */
+					/* Retry the command once more */
+					if (retry_cnt++ < 1) {
+						kfree(cmd_buf);
+						kfree(scsi_cmd);
+						goto retry;
+					}
+				}
+				break;
+			default:
+				break;
+			}
+		}
+	}
+
+	if (result) {
+		dev_err(dev, "%s: command failed, result=%08x\n",
+			__func__, result);
+		rc = -EIO;
+		goto out;
+	}
+
+	/*
+	 * Read cap was successful, grab values from the buffer;
+	 * note that we don't need to worry about unaligned access
+	 * as the buffer is allocated on an aligned boundary.
+	 */
+	mutex_lock(&gli->mutex);
+	gli->max_lba = be64_to_cpu(*((__be64 *)&cmd_buf[0]));
+	gli->blk_len = be32_to_cpu(*((__be32 *)&cmd_buf[8]));
+	mutex_unlock(&gli->mutex);
+
+out:
+	kfree(cmd_buf);
+	kfree(scsi_cmd);
+
+	dev_dbg(dev, "%s: maxlba=%lld blklen=%d rc=%d\n",
+		__func__, gli->max_lba, gli->blk_len, rc);
+	return rc;
+}
+
+/**
+ * get_rhte() - obtains validated resource handle table entry reference
+ * @ctxi:	Context owning the resource handle.
+ * @rhndl:	Resource handle associated with entry.
+ * @lli:	LUN associated with request.
+ *
+ * Return: Validated RHTE on success, NULL on failure
+ */
+struct sisl_rht_entry *get_rhte(struct ctx_info *ctxi, res_hndl_t rhndl,
+				struct llun_info *lli)
+{
+	struct cxlflash_cfg *cfg = ctxi->cfg;
+	struct device *dev = &cfg->dev->dev;
+	struct sisl_rht_entry *rhte = NULL;
+
+	if (unlikely(!ctxi->rht_start)) {
+		dev_dbg(dev, "%s: Context does not have allocated RHT\n",
+			 __func__);
+		goto out;
+	}
+
+	if (unlikely(rhndl >= MAX_RHT_PER_CONTEXT)) {
+		dev_dbg(dev, "%s: Bad resource handle rhndl=%d\n",
+			__func__, rhndl);
+		goto out;
+	}
+
+	if (unlikely(ctxi->rht_lun[rhndl] != lli)) {
+		dev_dbg(dev, "%s: Bad resource handle LUN rhndl=%d\n",
+			__func__, rhndl);
+		goto out;
+	}
+
+	rhte = &ctxi->rht_start[rhndl];
+	if (unlikely(rhte->nmask == 0)) {
+		dev_dbg(dev, "%s: Unopened resource handle rhndl=%d\n",
+			__func__, rhndl);
+		rhte = NULL;
+		goto out;
+	}
+
+out:
+	return rhte;
+}
+
+/**
+ * rhte_checkout() - obtains free/empty resource handle table entry
+ * @ctxi:	Context owning the resource handle.
+ * @lli:	LUN associated with request.
+ *
+ * Return: Free RHTE on success, NULL on failure
+ */
+struct sisl_rht_entry *rhte_checkout(struct ctx_info *ctxi,
+				     struct llun_info *lli)
+{
+	struct cxlflash_cfg *cfg = ctxi->cfg;
+	struct device *dev = &cfg->dev->dev;
+	struct sisl_rht_entry *rhte = NULL;
+	int i;
+
+	/* Find a free RHT entry */
+	for (i = 0; i < MAX_RHT_PER_CONTEXT; i++)
+		if (ctxi->rht_start[i].nmask == 0) {
+			rhte = &ctxi->rht_start[i];
+			ctxi->rht_out++;
+			break;
+		}
+
+	if (likely(rhte))
+		ctxi->rht_lun[i] = lli;
+
+	dev_dbg(dev, "%s: returning rhte=%p index=%d\n", __func__, rhte, i);
+	return rhte;
+}
+
+/**
+ * rhte_checkin() - releases a resource handle table entry
+ * @ctxi:	Context owning the resource handle.
+ * @rhte:	RHTE to release.
+ */
+void rhte_checkin(struct ctx_info *ctxi,
+		  struct sisl_rht_entry *rhte)
+{
+	u32 rsrc_handle = rhte - ctxi->rht_start;
+
+	rhte->nmask = 0;
+	rhte->fp = 0;
+	ctxi->rht_out--;
+	ctxi->rht_lun[rsrc_handle] = NULL;
+	ctxi->rht_needs_ws[rsrc_handle] = false;
+}
+
+/**
+ * rhte_format1() - populates a RHTE for format 1
+ * @rhte:	RHTE to populate.
+ * @lun_id:	LUN ID of LUN associated with RHTE.
+ * @perm:	Desired permissions for RHTE.
+ * @port_sel:	Port selection mask
+ */
+static void rht_format1(struct sisl_rht_entry *rhte, u64 lun_id, u32 perm,
+			u32 port_sel)
+{
+	/*
+	 * Populate the Format 1 RHT entry for direct access (physical
+	 * LUN) using the synchronization sequence defined in the
+	 * SISLite specification.
+	 */
+	struct sisl_rht_entry_f1 dummy = { 0 };
+	struct sisl_rht_entry_f1 *rhte_f1 = (struct sisl_rht_entry_f1 *)rhte;
+
+	memset(rhte_f1, 0, sizeof(*rhte_f1));
+	rhte_f1->fp = SISL_RHT_FP(1U, 0);
+	dma_wmb(); /* Make setting of format bit visible */
+
+	rhte_f1->lun_id = lun_id;
+	dma_wmb(); /* Make setting of LUN id visible */
+
+	/*
+	 * Use a dummy RHT Format 1 entry to build the second dword
+	 * of the entry that must be populated in a single write when
+	 * enabled (valid bit set to TRUE).
+	 */
+	dummy.valid = 0x80;
+	dummy.fp = SISL_RHT_FP(1U, perm);
+	dummy.port_sel = port_sel;
+	rhte_f1->dw = dummy.dw;
+
+	dma_wmb(); /* Make remaining RHT entry fields visible */
+}
+
+/**
+ * cxlflash_lun_attach() - attaches a user to a LUN and manages the LUN's mode
+ * @gli:	LUN to attach.
+ * @mode:	Desired mode of the LUN.
+ * @locked:	Mutex status on current thread.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+int cxlflash_lun_attach(struct glun_info *gli, enum lun_mode mode, bool locked)
+{
+	int rc = 0;
+
+	if (!locked)
+		mutex_lock(&gli->mutex);
+
+	if (gli->mode == MODE_NONE)
+		gli->mode = mode;
+	else if (gli->mode != mode) {
+		pr_debug("%s: gli_mode=%d requested_mode=%d\n",
+			 __func__, gli->mode, mode);
+		rc = -EINVAL;
+		goto out;
+	}
+
+	gli->users++;
+	WARN_ON(gli->users <= 0);
+out:
+	pr_debug("%s: Returning rc=%d gli->mode=%u gli->users=%u\n",
+		 __func__, rc, gli->mode, gli->users);
+	if (!locked)
+		mutex_unlock(&gli->mutex);
+	return rc;
+}
+
+/**
+ * cxlflash_lun_detach() - detaches a user from a LUN and resets the LUN's mode
+ * @gli:	LUN to detach.
+ *
+ * When resetting the mode, terminate block allocation resources as they
+ * are no longer required (service is safe to call even when block allocation
+ * resources were not present - such as when transitioning from physical mode).
+ * These resources will be reallocated when needed (subsequent transition to
+ * virtual mode).
+ */
+void cxlflash_lun_detach(struct glun_info *gli)
+{
+	mutex_lock(&gli->mutex);
+	WARN_ON(gli->mode == MODE_NONE);
+	if (--gli->users == 0) {
+		gli->mode = MODE_NONE;
+		cxlflash_ba_terminate(&gli->blka.ba_lun);
+	}
+	pr_debug("%s: gli->users=%u\n", __func__, gli->users);
+	WARN_ON(gli->users < 0);
+	mutex_unlock(&gli->mutex);
+}
+
+/**
+ * _cxlflash_disk_release() - releases the specified resource entry
+ * @sdev:	SCSI device associated with LUN.
+ * @ctxi:	Context owning resources.
+ * @release:	Release ioctl data structure.
+ *
+ * For LUNs in virtual mode, the virtual LUN associated with the specified
+ * resource handle is resized to 0 prior to releasing the RHTE. Note that the
+ * AFU sync should _not_ be performed when the context is sitting on the error
+ * recovery list. A context on the error recovery list is not known to the AFU
+ * due to reset. When the context is recovered, it will be reattached and made
+ * known again to the AFU.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+int _cxlflash_disk_release(struct scsi_device *sdev,
+			   struct ctx_info *ctxi,
+			   struct dk_cxlflash_release *release)
+{
+	struct cxlflash_cfg *cfg = shost_priv(sdev->host);
+	struct device *dev = &cfg->dev->dev;
+	struct llun_info *lli = sdev->hostdata;
+	struct glun_info *gli = lli->parent;
+	struct afu *afu = cfg->afu;
+	bool put_ctx = false;
+
+	struct dk_cxlflash_resize size;
+	res_hndl_t rhndl = release->rsrc_handle;
+
+	int rc = 0;
+	int rcr = 0;
+	u64 ctxid = DECODE_CTXID(release->context_id),
+	    rctxid = release->context_id;
+
+	struct sisl_rht_entry *rhte;
+	struct sisl_rht_entry_f1 *rhte_f1;
+
+	dev_dbg(dev, "%s: ctxid=%llu rhndl=%llu gli->mode=%u gli->users=%u\n",
+		__func__, ctxid, release->rsrc_handle, gli->mode, gli->users);
+
+	if (!ctxi) {
+		ctxi = get_context(cfg, rctxid, lli, CTX_CTRL_ERR_FALLBACK);
+		if (unlikely(!ctxi)) {
+			dev_dbg(dev, "%s: Bad context ctxid=%llu\n",
+				__func__, ctxid);
+			rc = -EINVAL;
+			goto out;
+		}
+
+		put_ctx = true;
+	}
+
+	rhte = get_rhte(ctxi, rhndl, lli);
+	if (unlikely(!rhte)) {
+		dev_dbg(dev, "%s: Bad resource handle rhndl=%d\n",
+			__func__, rhndl);
+		rc = -EINVAL;
+		goto out;
+	}
+
+	/*
+	 * Resize to 0 for virtual LUNS by setting the size
+	 * to 0. This will clear LXT_START and LXT_CNT fields
+	 * in the RHT entry and properly sync with the AFU.
+	 *
+	 * Afterwards we clear the remaining fields.
+	 */
+	switch (gli->mode) {
+	case MODE_VIRTUAL:
+		marshal_rele_to_resize(release, &size);
+		size.req_size = 0;
+		rc = _cxlflash_vlun_resize(sdev, ctxi, &size);
+		if (rc) {
+			dev_dbg(dev, "%s: resize failed rc %d\n", __func__, rc);
+			goto out;
+		}
+
+		break;
+	case MODE_PHYSICAL:
+		/*
+		 * Clear the Format 1 RHT entry for direct access
+		 * (physical LUN) using the synchronization sequence
+		 * defined in the SISLite specification.
+		 */
+		rhte_f1 = (struct sisl_rht_entry_f1 *)rhte;
+
+		rhte_f1->valid = 0;
+		dma_wmb(); /* Make revocation of RHT entry visible */
+
+		rhte_f1->lun_id = 0;
+		dma_wmb(); /* Make clearing of LUN id visible */
+
+		rhte_f1->dw = 0;
+		dma_wmb(); /* Make RHT entry bottom-half clearing visible */
+
+		if (!ctxi->err_recovery_active) {
+			rcr = cxlflash_afu_sync(afu, ctxid, rhndl, AFU_HW_SYNC);
+			if (unlikely(rcr))
+				dev_dbg(dev, "%s: AFU sync failed rc=%d\n",
+					__func__, rcr);
+		}
+		break;
+	default:
+		WARN(1, "Unsupported LUN mode!");
+		goto out;
+	}
+
+	rhte_checkin(ctxi, rhte);
+	cxlflash_lun_detach(gli);
+
+out:
+	if (put_ctx)
+		put_context(ctxi);
+	dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
+	return rc;
+}
+
+int cxlflash_disk_release(struct scsi_device *sdev,
+			  struct dk_cxlflash_release *release)
+{
+	return _cxlflash_disk_release(sdev, NULL, release);
+}
+
+/**
+ * destroy_context() - releases a context
+ * @cfg:	Internal structure associated with the host.
+ * @ctxi:	Context to release.
+ *
+ * This routine is safe to be called with a a non-initialized context.
+ * Also note that the routine conditionally checks for the existence
+ * of the context control map before clearing the RHT registers and
+ * context capabilities because it is possible to destroy a context
+ * while the context is in the error state (previous mapping was
+ * removed [so there is no need to worry about clearing] and context
+ * is waiting for a new mapping).
+ */
+static void destroy_context(struct cxlflash_cfg *cfg,
+			    struct ctx_info *ctxi)
+{
+	struct afu *afu = cfg->afu;
+
+	if (ctxi->initialized) {
+		WARN_ON(!list_empty(&ctxi->luns));
+
+		/* Clear RHT registers and drop all capabilities for context */
+		if (afu->afu_map && ctxi->ctrl_map) {
+			writeq_be(0, &ctxi->ctrl_map->rht_start);
+			writeq_be(0, &ctxi->ctrl_map->rht_cnt_id);
+			writeq_be(0, &ctxi->ctrl_map->ctx_cap);
+		}
+	}
+
+	/* Free memory associated with context */
+	free_page((ulong)ctxi->rht_start);
+	kfree(ctxi->rht_needs_ws);
+	kfree(ctxi->rht_lun);
+	kfree(ctxi);
+}
+
+/**
+ * create_context() - allocates and initializes a context
+ * @cfg:	Internal structure associated with the host.
+ *
+ * Return: Allocated context on success, NULL on failure
+ */
+static struct ctx_info *create_context(struct cxlflash_cfg *cfg)
+{
+	struct device *dev = &cfg->dev->dev;
+	struct ctx_info *ctxi = NULL;
+	struct llun_info **lli = NULL;
+	u8 *ws = NULL;
+	struct sisl_rht_entry *rhte;
+
+	ctxi = kzalloc(sizeof(*ctxi), GFP_KERNEL);
+	lli = kzalloc((MAX_RHT_PER_CONTEXT * sizeof(*lli)), GFP_KERNEL);
+	ws = kzalloc((MAX_RHT_PER_CONTEXT * sizeof(*ws)), GFP_KERNEL);
+	if (unlikely(!ctxi || !lli || !ws)) {
+		dev_err(dev, "%s: Unable to allocate context\n", __func__);
+		goto err;
+	}
+
+	rhte = (struct sisl_rht_entry *)get_zeroed_page(GFP_KERNEL);
+	if (unlikely(!rhte)) {
+		dev_err(dev, "%s: Unable to allocate RHT\n", __func__);
+		goto err;
+	}
+
+	ctxi->rht_lun = lli;
+	ctxi->rht_needs_ws = ws;
+	ctxi->rht_start = rhte;
+out:
+	return ctxi;
+
+err:
+	kfree(ws);
+	kfree(lli);
+	kfree(ctxi);
+	ctxi = NULL;
+	goto out;
+}
+
+/**
+ * init_context() - initializes a previously allocated context
+ * @ctxi:	Previously allocated context
+ * @cfg:	Internal structure associated with the host.
+ * @ctx:	Previously obtained context cookie.
+ * @ctxid:	Previously obtained process element associated with CXL context.
+ * @file:	Previously obtained file associated with CXL context.
+ * @perms:	User-specified permissions.
+ * @irqs:	User-specified number of interrupts.
+ */
+static void init_context(struct ctx_info *ctxi, struct cxlflash_cfg *cfg,
+			 void *ctx, int ctxid, struct file *file, u32 perms,
+			 u64 irqs)
+{
+	struct afu *afu = cfg->afu;
+
+	ctxi->rht_perms = perms;
+	ctxi->ctrl_map = &afu->afu_map->ctrls[ctxid].ctrl;
+	ctxi->ctxid = ENCODE_CTXID(ctxi, ctxid);
+	ctxi->irqs = irqs;
+	ctxi->pid = task_tgid_nr(current); /* tgid = pid */
+	ctxi->ctx = ctx;
+	ctxi->cfg = cfg;
+	ctxi->file = file;
+	ctxi->initialized = true;
+	mutex_init(&ctxi->mutex);
+	kref_init(&ctxi->kref);
+	INIT_LIST_HEAD(&ctxi->luns);
+	INIT_LIST_HEAD(&ctxi->list); /* initialize for list_empty() */
+}
+
+/**
+ * remove_context() - context kref release handler
+ * @kref:	Kernel reference associated with context to be removed.
+ *
+ * When a context no longer has any references it can safely be removed
+ * from global access and destroyed. Note that it is assumed the thread
+ * relinquishing access to the context holds its mutex.
+ */
+static void remove_context(struct kref *kref)
+{
+	struct ctx_info *ctxi = container_of(kref, struct ctx_info, kref);
+	struct cxlflash_cfg *cfg = ctxi->cfg;
+	u64 ctxid = DECODE_CTXID(ctxi->ctxid);
+
+	/* Remove context from table/error list */
+	WARN_ON(!mutex_is_locked(&ctxi->mutex));
+	ctxi->unavail = true;
+	mutex_unlock(&ctxi->mutex);
+	mutex_lock(&cfg->ctx_tbl_list_mutex);
+	mutex_lock(&ctxi->mutex);
+
+	if (!list_empty(&ctxi->list))
+		list_del(&ctxi->list);
+	cfg->ctx_tbl[ctxid] = NULL;
+	mutex_unlock(&cfg->ctx_tbl_list_mutex);
+	mutex_unlock(&ctxi->mutex);
+
+	/* Context now completely uncoupled/unreachable */
+	destroy_context(cfg, ctxi);
+}
+
+/**
+ * _cxlflash_disk_detach() - detaches a LUN from a context
+ * @sdev:	SCSI device associated with LUN.
+ * @ctxi:	Context owning resources.
+ * @detach:	Detach ioctl data structure.
+ *
+ * As part of the detach, all per-context resources associated with the LUN
+ * are cleaned up. When detaching the last LUN for a context, the context
+ * itself is cleaned up and released.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int _cxlflash_disk_detach(struct scsi_device *sdev,
+				 struct ctx_info *ctxi,
+				 struct dk_cxlflash_detach *detach)
+{
+	struct cxlflash_cfg *cfg = shost_priv(sdev->host);
+	struct device *dev = &cfg->dev->dev;
+	struct llun_info *lli = sdev->hostdata;
+	struct lun_access *lun_access, *t;
+	struct dk_cxlflash_release rel;
+	bool put_ctx = false;
+
+	int i;
+	int rc = 0;
+	u64 ctxid = DECODE_CTXID(detach->context_id),
+	    rctxid = detach->context_id;
+
+	dev_dbg(dev, "%s: ctxid=%llu\n", __func__, ctxid);
+
+	if (!ctxi) {
+		ctxi = get_context(cfg, rctxid, lli, CTX_CTRL_ERR_FALLBACK);
+		if (unlikely(!ctxi)) {
+			dev_dbg(dev, "%s: Bad context ctxid=%llu\n",
+				__func__, ctxid);
+			rc = -EINVAL;
+			goto out;
+		}
+
+		put_ctx = true;
+	}
+
+	/* Cleanup outstanding resources tied to this LUN */
+	if (ctxi->rht_out) {
+		marshal_det_to_rele(detach, &rel);
+		for (i = 0; i < MAX_RHT_PER_CONTEXT; i++) {
+			if (ctxi->rht_lun[i] == lli) {
+				rel.rsrc_handle = i;
+				_cxlflash_disk_release(sdev, ctxi, &rel);
+			}
+
+			/* No need to loop further if we're done */
+			if (ctxi->rht_out == 0)
+				break;
+		}
+	}
+
+	/* Take our LUN out of context, free the node */
+	list_for_each_entry_safe(lun_access, t, &ctxi->luns, list)
+		if (lun_access->lli == lli) {
+			list_del(&lun_access->list);
+			kfree(lun_access);
+			lun_access = NULL;
+			break;
+		}
+
+	/*
+	 * Release the context reference and the sdev reference that
+	 * bound this LUN to the context.
+	 */
+	if (kref_put(&ctxi->kref, remove_context))
+		put_ctx = false;
+	scsi_device_put(sdev);
+out:
+	if (put_ctx)
+		put_context(ctxi);
+	dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
+	return rc;
+}
+
+static int cxlflash_disk_detach(struct scsi_device *sdev,
+				struct dk_cxlflash_detach *detach)
+{
+	return _cxlflash_disk_detach(sdev, NULL, detach);
+}
+
+/**
+ * cxlflash_cxl_release() - release handler for adapter file descriptor
+ * @inode:	File-system inode associated with fd.
+ * @file:	File installed with adapter file descriptor.
+ *
+ * This routine is the release handler for the fops registered with
+ * the CXL services on an initial attach for a context. It is called
+ * when a close (explicity by the user or as part of a process tear
+ * down) is performed on the adapter file descriptor returned to the
+ * user. The user should be aware that explicitly performing a close
+ * considered catastrophic and subsequent usage of the superpipe API
+ * with previously saved off tokens will fail.
+ *
+ * This routine derives the context reference and calls detach for
+ * each LUN associated with the context.The final detach operation
+ * causes the context itself to be freed. With exception to when the
+ * CXL process element (context id) lookup fails (a case that should
+ * theoretically never occur), every call into this routine results
+ * in a complete freeing of a context.
+ *
+ * Detaching the LUN is typically an ioctl() operation and the underlying
+ * code assumes that ioctl_rwsem has been acquired as a reader. To support
+ * that design point, the semaphore is acquired and released around detach.
+ *
+ * Return: 0 on success
+ */
+static int cxlflash_cxl_release(struct inode *inode, struct file *file)
+{
+	struct cxlflash_cfg *cfg = container_of(file->f_op, struct cxlflash_cfg,
+						cxl_fops);
+	void *ctx = cfg->ops->fops_get_context(file);
+	struct device *dev = &cfg->dev->dev;
+	struct ctx_info *ctxi = NULL;
+	struct dk_cxlflash_detach detach = { { 0 }, 0 };
+	struct lun_access *lun_access, *t;
+	enum ctx_ctrl ctrl = CTX_CTRL_ERR_FALLBACK | CTX_CTRL_FILE;
+	int ctxid;
+
+	ctxid = cfg->ops->process_element(ctx);
+	if (unlikely(ctxid < 0)) {
+		dev_err(dev, "%s: Context %p was closed ctxid=%d\n",
+			__func__, ctx, ctxid);
+		goto out;
+	}
+
+	ctxi = get_context(cfg, ctxid, file, ctrl);
+	if (unlikely(!ctxi)) {
+		ctxi = get_context(cfg, ctxid, file, ctrl | CTX_CTRL_CLONE);
+		if (!ctxi) {
+			dev_dbg(dev, "%s: ctxid=%d already free\n",
+				__func__, ctxid);
+			goto out_release;
+		}
+
+		dev_dbg(dev, "%s: Another process owns ctxid=%d\n",
+			__func__, ctxid);
+		put_context(ctxi);
+		goto out;
+	}
+
+	dev_dbg(dev, "%s: close for ctxid=%d\n", __func__, ctxid);
+
+	down_read(&cfg->ioctl_rwsem);
+	detach.context_id = ctxi->ctxid;
+	list_for_each_entry_safe(lun_access, t, &ctxi->luns, list)
+		_cxlflash_disk_detach(lun_access->sdev, ctxi, &detach);
+	up_read(&cfg->ioctl_rwsem);
+out_release:
+	cfg->ops->fd_release(inode, file);
+out:
+	dev_dbg(dev, "%s: returning\n", __func__);
+	return 0;
+}
+
+/**
+ * unmap_context() - clears a previously established mapping
+ * @ctxi:	Context owning the mapping.
+ *
+ * This routine is used to switch between the error notification page
+ * (dummy page of all 1's) and the real mapping (established by the CXL
+ * fault handler).
+ */
+static void unmap_context(struct ctx_info *ctxi)
+{
+	unmap_mapping_range(ctxi->file->f_mapping, 0, 0, 1);
+}
+
+/**
+ * get_err_page() - obtains and allocates the error notification page
+ * @cfg:	Internal structure associated with the host.
+ *
+ * Return: error notification page on success, NULL on failure
+ */
+static struct page *get_err_page(struct cxlflash_cfg *cfg)
+{
+	struct page *err_page = global.err_page;
+	struct device *dev = &cfg->dev->dev;
+
+	if (unlikely(!err_page)) {
+		err_page = alloc_page(GFP_KERNEL);
+		if (unlikely(!err_page)) {
+			dev_err(dev, "%s: Unable to allocate err_page\n",
+				__func__);
+			goto out;
+		}
+
+		memset(page_address(err_page), -1, PAGE_SIZE);
+
+		/* Serialize update w/ other threads to avoid a leak */
+		mutex_lock(&global.mutex);
+		if (likely(!global.err_page))
+			global.err_page = err_page;
+		else {
+			__free_page(err_page);
+			err_page = global.err_page;
+		}
+		mutex_unlock(&global.mutex);
+	}
+
+out:
+	dev_dbg(dev, "%s: returning err_page=%p\n", __func__, err_page);
+	return err_page;
+}
+
+/**
+ * cxlflash_mmap_fault() - mmap fault handler for adapter file descriptor
+ * @vmf:	VM fault associated with current fault.
+ *
+ * To support error notification via MMIO, faults are 'caught' by this routine
+ * that was inserted before passing back the adapter file descriptor on attach.
+ * When a fault occurs, this routine evaluates if error recovery is active and
+ * if so, installs the error page to 'notify' the user about the error state.
+ * During normal operation, the fault is simply handled by the original fault
+ * handler that was installed by CXL services as part of initializing the
+ * adapter file descriptor. The VMA's page protection bits are toggled to
+ * indicate cached/not-cached depending on the memory backing the fault.
+ *
+ * Return: 0 on success, VM_FAULT_SIGBUS on failure
+ */
+static vm_fault_t cxlflash_mmap_fault(struct vm_fault *vmf)
+{
+	struct vm_area_struct *vma = vmf->vma;
+	struct file *file = vma->vm_file;
+	struct cxlflash_cfg *cfg = container_of(file->f_op, struct cxlflash_cfg,
+						cxl_fops);
+	void *ctx = cfg->ops->fops_get_context(file);
+	struct device *dev = &cfg->dev->dev;
+	struct ctx_info *ctxi = NULL;
+	struct page *err_page = NULL;
+	enum ctx_ctrl ctrl = CTX_CTRL_ERR_FALLBACK | CTX_CTRL_FILE;
+	vm_fault_t rc = 0;
+	int ctxid;
+
+	ctxid = cfg->ops->process_element(ctx);
+	if (unlikely(ctxid < 0)) {
+		dev_err(dev, "%s: Context %p was closed ctxid=%d\n",
+			__func__, ctx, ctxid);
+		goto err;
+	}
+
+	ctxi = get_context(cfg, ctxid, file, ctrl);
+	if (unlikely(!ctxi)) {
+		dev_dbg(dev, "%s: Bad context ctxid=%d\n", __func__, ctxid);
+		goto err;
+	}
+
+	dev_dbg(dev, "%s: fault for context %d\n", __func__, ctxid);
+
+	if (likely(!ctxi->err_recovery_active)) {
+		vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+		rc = ctxi->cxl_mmap_vmops->fault(vmf);
+	} else {
+		dev_dbg(dev, "%s: err recovery active, use err_page\n",
+			__func__);
+
+		err_page = get_err_page(cfg);
+		if (unlikely(!err_page)) {
+			dev_err(dev, "%s: Could not get err_page\n", __func__);
+			rc = VM_FAULT_RETRY;
+			goto out;
+		}
+
+		get_page(err_page);
+		vmf->page = err_page;
+		vma->vm_page_prot = pgprot_cached(vma->vm_page_prot);
+	}
+
+out:
+	if (likely(ctxi))
+		put_context(ctxi);
+	dev_dbg(dev, "%s: returning rc=%x\n", __func__, rc);
+	return rc;
+
+err:
+	rc = VM_FAULT_SIGBUS;
+	goto out;
+}
+
+/*
+ * Local MMAP vmops to 'catch' faults
+ */
+static const struct vm_operations_struct cxlflash_mmap_vmops = {
+	.fault = cxlflash_mmap_fault,
+};
+
+/**
+ * cxlflash_cxl_mmap() - mmap handler for adapter file descriptor
+ * @file:	File installed with adapter file descriptor.
+ * @vma:	VM area associated with mapping.
+ *
+ * Installs local mmap vmops to 'catch' faults for error notification support.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int cxlflash_cxl_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	struct cxlflash_cfg *cfg = container_of(file->f_op, struct cxlflash_cfg,
+						cxl_fops);
+	void *ctx = cfg->ops->fops_get_context(file);
+	struct device *dev = &cfg->dev->dev;
+	struct ctx_info *ctxi = NULL;
+	enum ctx_ctrl ctrl = CTX_CTRL_ERR_FALLBACK | CTX_CTRL_FILE;
+	int ctxid;
+	int rc = 0;
+
+	ctxid = cfg->ops->process_element(ctx);
+	if (unlikely(ctxid < 0)) {
+		dev_err(dev, "%s: Context %p was closed ctxid=%d\n",
+			__func__, ctx, ctxid);
+		rc = -EIO;
+		goto out;
+	}
+
+	ctxi = get_context(cfg, ctxid, file, ctrl);
+	if (unlikely(!ctxi)) {
+		dev_dbg(dev, "%s: Bad context ctxid=%d\n", __func__, ctxid);
+		rc = -EIO;
+		goto out;
+	}
+
+	dev_dbg(dev, "%s: mmap for context %d\n", __func__, ctxid);
+
+	rc = cfg->ops->fd_mmap(file, vma);
+	if (likely(!rc)) {
+		/* Insert ourself in the mmap fault handler path */
+		ctxi->cxl_mmap_vmops = vma->vm_ops;
+		vma->vm_ops = &cxlflash_mmap_vmops;
+	}
+
+out:
+	if (likely(ctxi))
+		put_context(ctxi);
+	return rc;
+}
+
+const struct file_operations cxlflash_cxl_fops = {
+	.owner = THIS_MODULE,
+	.mmap = cxlflash_cxl_mmap,
+	.release = cxlflash_cxl_release,
+};
+
+/**
+ * cxlflash_mark_contexts_error() - move contexts to error state and list
+ * @cfg:	Internal structure associated with the host.
+ *
+ * A context is only moved over to the error list when there are no outstanding
+ * references to it. This ensures that a running operation has completed.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+int cxlflash_mark_contexts_error(struct cxlflash_cfg *cfg)
+{
+	int i, rc = 0;
+	struct ctx_info *ctxi = NULL;
+
+	mutex_lock(&cfg->ctx_tbl_list_mutex);
+
+	for (i = 0; i < MAX_CONTEXT; i++) {
+		ctxi = cfg->ctx_tbl[i];
+		if (ctxi) {
+			mutex_lock(&ctxi->mutex);
+			cfg->ctx_tbl[i] = NULL;
+			list_add(&ctxi->list, &cfg->ctx_err_recovery);
+			ctxi->err_recovery_active = true;
+			ctxi->ctrl_map = NULL;
+			unmap_context(ctxi);
+			mutex_unlock(&ctxi->mutex);
+		}
+	}
+
+	mutex_unlock(&cfg->ctx_tbl_list_mutex);
+	return rc;
+}
+
+/*
+ * Dummy NULL fops
+ */
+static const struct file_operations null_fops = {
+	.owner = THIS_MODULE,
+};
+
+/**
+ * check_state() - checks and responds to the current adapter state
+ * @cfg:	Internal structure associated with the host.
+ *
+ * This routine can block and should only be used on process context.
+ * It assumes that the caller is an ioctl thread and holding the ioctl
+ * read semaphore. This is temporarily let up across the wait to allow
+ * for draining actively running ioctls. Also note that when waking up
+ * from waiting in reset, the state is unknown and must be checked again
+ * before proceeding.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+int check_state(struct cxlflash_cfg *cfg)
+{
+	struct device *dev = &cfg->dev->dev;
+	int rc = 0;
+
+retry:
+	switch (cfg->state) {
+	case STATE_RESET:
+		dev_dbg(dev, "%s: Reset state, going to wait...\n", __func__);
+		up_read(&cfg->ioctl_rwsem);
+		rc = wait_event_interruptible(cfg->reset_waitq,
+					      cfg->state != STATE_RESET);
+		down_read(&cfg->ioctl_rwsem);
+		if (unlikely(rc))
+			break;
+		goto retry;
+	case STATE_FAILTERM:
+		dev_dbg(dev, "%s: Failed/Terminating\n", __func__);
+		rc = -ENODEV;
+		break;
+	default:
+		break;
+	}
+
+	return rc;
+}
+
+/**
+ * cxlflash_disk_attach() - attach a LUN to a context
+ * @sdev:	SCSI device associated with LUN.
+ * @attach:	Attach ioctl data structure.
+ *
+ * Creates a context and attaches LUN to it. A LUN can only be attached
+ * one time to a context (subsequent attaches for the same context/LUN pair
+ * are not supported). Additional LUNs can be attached to a context by
+ * specifying the 'reuse' flag defined in the cxlflash_ioctl.h header.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int cxlflash_disk_attach(struct scsi_device *sdev,
+				struct dk_cxlflash_attach *attach)
+{
+	struct cxlflash_cfg *cfg = shost_priv(sdev->host);
+	struct device *dev = &cfg->dev->dev;
+	struct afu *afu = cfg->afu;
+	struct llun_info *lli = sdev->hostdata;
+	struct glun_info *gli = lli->parent;
+	struct ctx_info *ctxi = NULL;
+	struct lun_access *lun_access = NULL;
+	int rc = 0;
+	u32 perms;
+	int ctxid = -1;
+	u64 irqs = attach->num_interrupts;
+	u64 flags = 0UL;
+	u64 rctxid = 0UL;
+	struct file *file = NULL;
+
+	void *ctx = NULL;
+
+	int fd = -1;
+
+	if (irqs > 4) {
+		dev_dbg(dev, "%s: Cannot support this many interrupts %llu\n",
+			__func__, irqs);
+		rc = -EINVAL;
+		goto out;
+	}
+
+	if (gli->max_lba == 0) {
+		dev_dbg(dev, "%s: No capacity info for LUN=%016llx\n",
+			__func__, lli->lun_id[sdev->channel]);
+		rc = read_cap16(sdev, lli);
+		if (rc) {
+			dev_err(dev, "%s: Invalid device rc=%d\n",
+				__func__, rc);
+			rc = -ENODEV;
+			goto out;
+		}
+		dev_dbg(dev, "%s: LBA = %016llx\n", __func__, gli->max_lba);
+		dev_dbg(dev, "%s: BLK_LEN = %08x\n", __func__, gli->blk_len);
+	}
+
+	if (attach->hdr.flags & DK_CXLFLASH_ATTACH_REUSE_CONTEXT) {
+		rctxid = attach->context_id;
+		ctxi = get_context(cfg, rctxid, NULL, 0);
+		if (!ctxi) {
+			dev_dbg(dev, "%s: Bad context rctxid=%016llx\n",
+				__func__, rctxid);
+			rc = -EINVAL;
+			goto out;
+		}
+
+		list_for_each_entry(lun_access, &ctxi->luns, list)
+			if (lun_access->lli == lli) {
+				dev_dbg(dev, "%s: Already attached\n",
+					__func__);
+				rc = -EINVAL;
+				goto out;
+			}
+	}
+
+	rc = scsi_device_get(sdev);
+	if (unlikely(rc)) {
+		dev_err(dev, "%s: Unable to get sdev reference\n", __func__);
+		goto out;
+	}
+
+	lun_access = kzalloc(sizeof(*lun_access), GFP_KERNEL);
+	if (unlikely(!lun_access)) {
+		dev_err(dev, "%s: Unable to allocate lun_access\n", __func__);
+		rc = -ENOMEM;
+		goto err;
+	}
+
+	lun_access->lli = lli;
+	lun_access->sdev = sdev;
+
+	/* Non-NULL context indicates reuse (another context reference) */
+	if (ctxi) {
+		dev_dbg(dev, "%s: Reusing context for LUN rctxid=%016llx\n",
+			__func__, rctxid);
+		kref_get(&ctxi->kref);
+		list_add(&lun_access->list, &ctxi->luns);
+		goto out_attach;
+	}
+
+	ctxi = create_context(cfg);
+	if (unlikely(!ctxi)) {
+		dev_err(dev, "%s: Failed to create context ctxid=%d\n",
+			__func__, ctxid);
+		rc = -ENOMEM;
+		goto err;
+	}
+
+	ctx = cfg->ops->dev_context_init(cfg->dev, cfg->afu_cookie);
+	if (IS_ERR_OR_NULL(ctx)) {
+		dev_err(dev, "%s: Could not initialize context %p\n",
+			__func__, ctx);
+		rc = -ENODEV;
+		goto err;
+	}
+
+	rc = cfg->ops->start_work(ctx, irqs);
+	if (unlikely(rc)) {
+		dev_dbg(dev, "%s: Could not start context rc=%d\n",
+			__func__, rc);
+		goto err;
+	}
+
+	ctxid = cfg->ops->process_element(ctx);
+	if (unlikely((ctxid >= MAX_CONTEXT) || (ctxid < 0))) {
+		dev_err(dev, "%s: ctxid=%d invalid\n", __func__, ctxid);
+		rc = -EPERM;
+		goto err;
+	}
+
+	file = cfg->ops->get_fd(ctx, &cfg->cxl_fops, &fd);
+	if (unlikely(fd < 0)) {
+		rc = -ENODEV;
+		dev_err(dev, "%s: Could not get file descriptor\n", __func__);
+		goto err;
+	}
+
+	/* Translate read/write O_* flags from fcntl.h to AFU permission bits */
+	perms = SISL_RHT_PERM(attach->hdr.flags + 1);
+
+	/* Context mutex is locked upon return */
+	init_context(ctxi, cfg, ctx, ctxid, file, perms, irqs);
+
+	rc = afu_attach(cfg, ctxi);
+	if (unlikely(rc)) {
+		dev_err(dev, "%s: Could not attach AFU rc %d\n", __func__, rc);
+		goto err;
+	}
+
+	/*
+	 * No error paths after this point. Once the fd is installed it's
+	 * visible to user space and can't be undone safely on this thread.
+	 * There is no need to worry about a deadlock here because no one
+	 * knows about us yet; we can be the only one holding our mutex.
+	 */
+	list_add(&lun_access->list, &ctxi->luns);
+	mutex_lock(&cfg->ctx_tbl_list_mutex);
+	mutex_lock(&ctxi->mutex);
+	cfg->ctx_tbl[ctxid] = ctxi;
+	mutex_unlock(&cfg->ctx_tbl_list_mutex);
+	fd_install(fd, file);
+
+out_attach:
+	if (fd != -1)
+		flags |= DK_CXLFLASH_APP_CLOSE_ADAP_FD;
+	if (afu_is_sq_cmd_mode(afu))
+		flags |= DK_CXLFLASH_CONTEXT_SQ_CMD_MODE;
+
+	attach->hdr.return_flags = flags;
+	attach->context_id = ctxi->ctxid;
+	attach->block_size = gli->blk_len;
+	attach->mmio_size = sizeof(afu->afu_map->hosts[0].harea);
+	attach->last_lba = gli->max_lba;
+	attach->max_xfer = sdev->host->max_sectors * MAX_SECTOR_UNIT;
+	attach->max_xfer /= gli->blk_len;
+
+out:
+	attach->adap_fd = fd;
+
+	if (ctxi)
+		put_context(ctxi);
+
+	dev_dbg(dev, "%s: returning ctxid=%d fd=%d bs=%lld rc=%d llba=%lld\n",
+		__func__, ctxid, fd, attach->block_size, rc, attach->last_lba);
+	return rc;
+
+err:
+	/* Cleanup CXL context; okay to 'stop' even if it was not started */
+	if (!IS_ERR_OR_NULL(ctx)) {
+		cfg->ops->stop_context(ctx);
+		cfg->ops->release_context(ctx);
+		ctx = NULL;
+	}
+
+	/*
+	 * Here, we're overriding the fops with a dummy all-NULL fops because
+	 * fput() calls the release fop, which will cause us to mistakenly
+	 * call into the CXL code. Rather than try to add yet more complexity
+	 * to that routine (cxlflash_cxl_release) we should try to fix the
+	 * issue here.
+	 */
+	if (fd > 0) {
+		file->f_op = &null_fops;
+		fput(file);
+		put_unused_fd(fd);
+		fd = -1;
+		file = NULL;
+	}
+
+	/* Cleanup our context */
+	if (ctxi) {
+		destroy_context(cfg, ctxi);
+		ctxi = NULL;
+	}
+
+	kfree(lun_access);
+	scsi_device_put(sdev);
+	goto out;
+}
+
+/**
+ * recover_context() - recovers a context in error
+ * @cfg:	Internal structure associated with the host.
+ * @ctxi:	Context to release.
+ * @adap_fd:	Adapter file descriptor associated with new/recovered context.
+ *
+ * Restablishes the state for a context-in-error.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int recover_context(struct cxlflash_cfg *cfg,
+			   struct ctx_info *ctxi,
+			   int *adap_fd)
+{
+	struct device *dev = &cfg->dev->dev;
+	int rc = 0;
+	int fd = -1;
+	int ctxid = -1;
+	struct file *file;
+	void *ctx;
+	struct afu *afu = cfg->afu;
+
+	ctx = cfg->ops->dev_context_init(cfg->dev, cfg->afu_cookie);
+	if (IS_ERR_OR_NULL(ctx)) {
+		dev_err(dev, "%s: Could not initialize context %p\n",
+			__func__, ctx);
+		rc = -ENODEV;
+		goto out;
+	}
+
+	rc = cfg->ops->start_work(ctx, ctxi->irqs);
+	if (unlikely(rc)) {
+		dev_dbg(dev, "%s: Could not start context rc=%d\n",
+			__func__, rc);
+		goto err1;
+	}
+
+	ctxid = cfg->ops->process_element(ctx);
+	if (unlikely((ctxid >= MAX_CONTEXT) || (ctxid < 0))) {
+		dev_err(dev, "%s: ctxid=%d invalid\n", __func__, ctxid);
+		rc = -EPERM;
+		goto err2;
+	}
+
+	file = cfg->ops->get_fd(ctx, &cfg->cxl_fops, &fd);
+	if (unlikely(fd < 0)) {
+		rc = -ENODEV;
+		dev_err(dev, "%s: Could not get file descriptor\n", __func__);
+		goto err2;
+	}
+
+	/* Update with new MMIO area based on updated context id */
+	ctxi->ctrl_map = &afu->afu_map->ctrls[ctxid].ctrl;
+
+	rc = afu_attach(cfg, ctxi);
+	if (rc) {
+		dev_err(dev, "%s: Could not attach AFU rc %d\n", __func__, rc);
+		goto err3;
+	}
+
+	/*
+	 * No error paths after this point. Once the fd is installed it's
+	 * visible to user space and can't be undone safely on this thread.
+	 */
+	ctxi->ctxid = ENCODE_CTXID(ctxi, ctxid);
+	ctxi->ctx = ctx;
+	ctxi->file = file;
+
+	/*
+	 * Put context back in table (note the reinit of the context list);
+	 * we must first drop the context's mutex and then acquire it in
+	 * order with the table/list mutex to avoid a deadlock - safe to do
+	 * here because no one can find us at this moment in time.
+	 */
+	mutex_unlock(&ctxi->mutex);
+	mutex_lock(&cfg->ctx_tbl_list_mutex);
+	mutex_lock(&ctxi->mutex);
+	list_del_init(&ctxi->list);
+	cfg->ctx_tbl[ctxid] = ctxi;
+	mutex_unlock(&cfg->ctx_tbl_list_mutex);
+	fd_install(fd, file);
+	*adap_fd = fd;
+out:
+	dev_dbg(dev, "%s: returning ctxid=%d fd=%d rc=%d\n",
+		__func__, ctxid, fd, rc);
+	return rc;
+
+err3:
+	fput(file);
+	put_unused_fd(fd);
+err2:
+	cfg->ops->stop_context(ctx);
+err1:
+	cfg->ops->release_context(ctx);
+	goto out;
+}
+
+/**
+ * cxlflash_afu_recover() - initiates AFU recovery
+ * @sdev:	SCSI device associated with LUN.
+ * @recover:	Recover ioctl data structure.
+ *
+ * Only a single recovery is allowed at a time to avoid exhausting CXL
+ * resources (leading to recovery failure) in the event that we're up
+ * against the maximum number of contexts limit. For similar reasons,
+ * a context recovery is retried if there are multiple recoveries taking
+ * place at the same time and the failure was due to CXL services being
+ * unable to keep up.
+ *
+ * As this routine is called on ioctl context, it holds the ioctl r/w
+ * semaphore that is used to drain ioctls in recovery scenarios. The
+ * implementation to achieve the pacing described above (a local mutex)
+ * requires that the ioctl r/w semaphore be dropped and reacquired to
+ * avoid a 3-way deadlock when multiple process recoveries operate in
+ * parallel.
+ *
+ * Because a user can detect an error condition before the kernel, it is
+ * quite possible for this routine to act as the kernel's EEH detection
+ * source (MMIO read of mbox_r). Because of this, there is a window of
+ * time where an EEH might have been detected but not yet 'serviced'
+ * (callback invoked, causing the device to enter reset state). To avoid
+ * looping in this routine during that window, a 1 second sleep is in place
+ * between the time the MMIO failure is detected and the time a wait on the
+ * reset wait queue is attempted via check_state().
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int cxlflash_afu_recover(struct scsi_device *sdev,
+				struct dk_cxlflash_recover_afu *recover)
+{
+	struct cxlflash_cfg *cfg = shost_priv(sdev->host);
+	struct device *dev = &cfg->dev->dev;
+	struct llun_info *lli = sdev->hostdata;
+	struct afu *afu = cfg->afu;
+	struct ctx_info *ctxi = NULL;
+	struct mutex *mutex = &cfg->ctx_recovery_mutex;
+	struct hwq *hwq = get_hwq(afu, PRIMARY_HWQ);
+	u64 flags;
+	u64 ctxid = DECODE_CTXID(recover->context_id),
+	    rctxid = recover->context_id;
+	long reg;
+	bool locked = true;
+	int lretry = 20; /* up to 2 seconds */
+	int new_adap_fd = -1;
+	int rc = 0;
+
+	atomic_inc(&cfg->recovery_threads);
+	up_read(&cfg->ioctl_rwsem);
+	rc = mutex_lock_interruptible(mutex);
+	down_read(&cfg->ioctl_rwsem);
+	if (rc) {
+		locked = false;
+		goto out;
+	}
+
+	rc = check_state(cfg);
+	if (rc) {
+		dev_err(dev, "%s: Failed state rc=%d\n", __func__, rc);
+		rc = -ENODEV;
+		goto out;
+	}
+
+	dev_dbg(dev, "%s: reason=%016llx rctxid=%016llx\n",
+		__func__, recover->reason, rctxid);
+
+retry:
+	/* Ensure that this process is attached to the context */
+	ctxi = get_context(cfg, rctxid, lli, CTX_CTRL_ERR_FALLBACK);
+	if (unlikely(!ctxi)) {
+		dev_dbg(dev, "%s: Bad context ctxid=%llu\n", __func__, ctxid);
+		rc = -EINVAL;
+		goto out;
+	}
+
+	if (ctxi->err_recovery_active) {
+retry_recover:
+		rc = recover_context(cfg, ctxi, &new_adap_fd);
+		if (unlikely(rc)) {
+			dev_err(dev, "%s: Recovery failed ctxid=%llu rc=%d\n",
+				__func__, ctxid, rc);
+			if ((rc == -ENODEV) &&
+			    ((atomic_read(&cfg->recovery_threads) > 1) ||
+			     (lretry--))) {
+				dev_dbg(dev, "%s: Going to try again\n",
+					__func__);
+				mutex_unlock(mutex);
+				msleep(100);
+				rc = mutex_lock_interruptible(mutex);
+				if (rc) {
+					locked = false;
+					goto out;
+				}
+				goto retry_recover;
+			}
+
+			goto out;
+		}
+
+		ctxi->err_recovery_active = false;
+
+		flags = DK_CXLFLASH_APP_CLOSE_ADAP_FD |
+			DK_CXLFLASH_RECOVER_AFU_CONTEXT_RESET;
+		if (afu_is_sq_cmd_mode(afu))
+			flags |= DK_CXLFLASH_CONTEXT_SQ_CMD_MODE;
+
+		recover->hdr.return_flags = flags;
+		recover->context_id = ctxi->ctxid;
+		recover->adap_fd = new_adap_fd;
+		recover->mmio_size = sizeof(afu->afu_map->hosts[0].harea);
+		goto out;
+	}
+
+	/* Test if in error state */
+	reg = readq_be(&hwq->ctrl_map->mbox_r);
+	if (reg == -1) {
+		dev_dbg(dev, "%s: MMIO fail, wait for recovery.\n", __func__);
+
+		/*
+		 * Before checking the state, put back the context obtained with
+		 * get_context() as it is no longer needed and sleep for a short
+		 * period of time (see prolog notes).
+		 */
+		put_context(ctxi);
+		ctxi = NULL;
+		ssleep(1);
+		rc = check_state(cfg);
+		if (unlikely(rc))
+			goto out;
+		goto retry;
+	}
+
+	dev_dbg(dev, "%s: MMIO working, no recovery required\n", __func__);
+out:
+	if (likely(ctxi))
+		put_context(ctxi);
+	if (locked)
+		mutex_unlock(mutex);
+	atomic_dec_if_positive(&cfg->recovery_threads);
+	return rc;
+}
+
+/**
+ * process_sense() - evaluates and processes sense data
+ * @sdev:	SCSI device associated with LUN.
+ * @verify:	Verify ioctl data structure.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int process_sense(struct scsi_device *sdev,
+			 struct dk_cxlflash_verify *verify)
+{
+	struct cxlflash_cfg *cfg = shost_priv(sdev->host);
+	struct device *dev = &cfg->dev->dev;
+	struct llun_info *lli = sdev->hostdata;
+	struct glun_info *gli = lli->parent;
+	u64 prev_lba = gli->max_lba;
+	struct scsi_sense_hdr sshdr = { 0 };
+	int rc = 0;
+
+	rc = scsi_normalize_sense((const u8 *)&verify->sense_data,
+				  DK_CXLFLASH_VERIFY_SENSE_LEN, &sshdr);
+	if (!rc) {
+		dev_err(dev, "%s: Failed to normalize sense data\n", __func__);
+		rc = -EINVAL;
+		goto out;
+	}
+
+	switch (sshdr.sense_key) {
+	case NO_SENSE:
+	case RECOVERED_ERROR:
+	case NOT_READY:
+		break;
+	case UNIT_ATTENTION:
+		switch (sshdr.asc) {
+		case 0x29: /* Power on Reset or Device Reset */
+			fallthrough;
+		case 0x2A: /* Device settings/capacity changed */
+			rc = read_cap16(sdev, lli);
+			if (rc) {
+				rc = -ENODEV;
+				break;
+			}
+			if (prev_lba != gli->max_lba)
+				dev_dbg(dev, "%s: Capacity changed old=%lld "
+					"new=%lld\n", __func__, prev_lba,
+					gli->max_lba);
+			break;
+		case 0x3F: /* Report LUNs changed, Rescan. */
+			scsi_scan_host(cfg->host);
+			break;
+		default:
+			rc = -EIO;
+			break;
+		}
+		break;
+	default:
+		rc = -EIO;
+		break;
+	}
+out:
+	dev_dbg(dev, "%s: sense_key %x asc %x ascq %x rc %d\n", __func__,
+		sshdr.sense_key, sshdr.asc, sshdr.ascq, rc);
+	return rc;
+}
+
+/**
+ * cxlflash_disk_verify() - verifies a LUN is the same and handle size changes
+ * @sdev:	SCSI device associated with LUN.
+ * @verify:	Verify ioctl data structure.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int cxlflash_disk_verify(struct scsi_device *sdev,
+				struct dk_cxlflash_verify *verify)
+{
+	int rc = 0;
+	struct ctx_info *ctxi = NULL;
+	struct cxlflash_cfg *cfg = shost_priv(sdev->host);
+	struct device *dev = &cfg->dev->dev;
+	struct llun_info *lli = sdev->hostdata;
+	struct glun_info *gli = lli->parent;
+	struct sisl_rht_entry *rhte = NULL;
+	res_hndl_t rhndl = verify->rsrc_handle;
+	u64 ctxid = DECODE_CTXID(verify->context_id),
+	    rctxid = verify->context_id;
+	u64 last_lba = 0;
+
+	dev_dbg(dev, "%s: ctxid=%llu rhndl=%016llx, hint=%016llx, "
+		"flags=%016llx\n", __func__, ctxid, verify->rsrc_handle,
+		verify->hint, verify->hdr.flags);
+
+	ctxi = get_context(cfg, rctxid, lli, 0);
+	if (unlikely(!ctxi)) {
+		dev_dbg(dev, "%s: Bad context ctxid=%llu\n", __func__, ctxid);
+		rc = -EINVAL;
+		goto out;
+	}
+
+	rhte = get_rhte(ctxi, rhndl, lli);
+	if (unlikely(!rhte)) {
+		dev_dbg(dev, "%s: Bad resource handle rhndl=%d\n",
+			__func__, rhndl);
+		rc = -EINVAL;
+		goto out;
+	}
+
+	/*
+	 * Look at the hint/sense to see if it requires us to redrive
+	 * inquiry (i.e. the Unit attention is due to the WWN changing).
+	 */
+	if (verify->hint & DK_CXLFLASH_VERIFY_HINT_SENSE) {
+		/* Can't hold mutex across process_sense/read_cap16,
+		 * since we could have an intervening EEH event.
+		 */
+		ctxi->unavail = true;
+		mutex_unlock(&ctxi->mutex);
+		rc = process_sense(sdev, verify);
+		if (unlikely(rc)) {
+			dev_err(dev, "%s: Failed to validate sense data (%d)\n",
+				__func__, rc);
+			mutex_lock(&ctxi->mutex);
+			ctxi->unavail = false;
+			goto out;
+		}
+		mutex_lock(&ctxi->mutex);
+		ctxi->unavail = false;
+	}
+
+	switch (gli->mode) {
+	case MODE_PHYSICAL:
+		last_lba = gli->max_lba;
+		break;
+	case MODE_VIRTUAL:
+		/* Cast lxt_cnt to u64 for multiply to be treated as 64bit op */
+		last_lba = ((u64)rhte->lxt_cnt * MC_CHUNK_SIZE * gli->blk_len);
+		last_lba /= CXLFLASH_BLOCK_SIZE;
+		last_lba--;
+		break;
+	default:
+		WARN(1, "Unsupported LUN mode!");
+	}
+
+	verify->last_lba = last_lba;
+
+out:
+	if (likely(ctxi))
+		put_context(ctxi);
+	dev_dbg(dev, "%s: returning rc=%d llba=%llx\n",
+		__func__, rc, verify->last_lba);
+	return rc;
+}
+
+/**
+ * decode_ioctl() - translates an encoded ioctl to an easily identifiable string
+ * @cmd:	The ioctl command to decode.
+ *
+ * Return: A string identifying the decoded ioctl.
+ */
+static char *decode_ioctl(unsigned int cmd)
+{
+	switch (cmd) {
+	case DK_CXLFLASH_ATTACH:
+		return __stringify_1(DK_CXLFLASH_ATTACH);
+	case DK_CXLFLASH_USER_DIRECT:
+		return __stringify_1(DK_CXLFLASH_USER_DIRECT);
+	case DK_CXLFLASH_USER_VIRTUAL:
+		return __stringify_1(DK_CXLFLASH_USER_VIRTUAL);
+	case DK_CXLFLASH_VLUN_RESIZE:
+		return __stringify_1(DK_CXLFLASH_VLUN_RESIZE);
+	case DK_CXLFLASH_RELEASE:
+		return __stringify_1(DK_CXLFLASH_RELEASE);
+	case DK_CXLFLASH_DETACH:
+		return __stringify_1(DK_CXLFLASH_DETACH);
+	case DK_CXLFLASH_VERIFY:
+		return __stringify_1(DK_CXLFLASH_VERIFY);
+	case DK_CXLFLASH_VLUN_CLONE:
+		return __stringify_1(DK_CXLFLASH_VLUN_CLONE);
+	case DK_CXLFLASH_RECOVER_AFU:
+		return __stringify_1(DK_CXLFLASH_RECOVER_AFU);
+	case DK_CXLFLASH_MANAGE_LUN:
+		return __stringify_1(DK_CXLFLASH_MANAGE_LUN);
+	}
+
+	return "UNKNOWN";
+}
+
+/**
+ * cxlflash_disk_direct_open() - opens a direct (physical) disk
+ * @sdev:	SCSI device associated with LUN.
+ * @arg:	UDirect ioctl data structure.
+ *
+ * On successful return, the user is informed of the resource handle
+ * to be used to identify the direct lun and the size (in blocks) of
+ * the direct lun in last LBA format.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int cxlflash_disk_direct_open(struct scsi_device *sdev, void *arg)
+{
+	struct cxlflash_cfg *cfg = shost_priv(sdev->host);
+	struct device *dev = &cfg->dev->dev;
+	struct afu *afu = cfg->afu;
+	struct llun_info *lli = sdev->hostdata;
+	struct glun_info *gli = lli->parent;
+	struct dk_cxlflash_release rel = { { 0 }, 0 };
+
+	struct dk_cxlflash_udirect *pphys = (struct dk_cxlflash_udirect *)arg;
+
+	u64 ctxid = DECODE_CTXID(pphys->context_id),
+	    rctxid = pphys->context_id;
+	u64 lun_size = 0;
+	u64 last_lba = 0;
+	u64 rsrc_handle = -1;
+	u32 port = CHAN2PORTMASK(sdev->channel);
+
+	int rc = 0;
+
+	struct ctx_info *ctxi = NULL;
+	struct sisl_rht_entry *rhte = NULL;
+
+	dev_dbg(dev, "%s: ctxid=%llu ls=%llu\n", __func__, ctxid, lun_size);
+
+	rc = cxlflash_lun_attach(gli, MODE_PHYSICAL, false);
+	if (unlikely(rc)) {
+		dev_dbg(dev, "%s: Failed attach to LUN (PHYSICAL)\n", __func__);
+		goto out;
+	}
+
+	ctxi = get_context(cfg, rctxid, lli, 0);
+	if (unlikely(!ctxi)) {
+		dev_dbg(dev, "%s: Bad context ctxid=%llu\n", __func__, ctxid);
+		rc = -EINVAL;
+		goto err1;
+	}
+
+	rhte = rhte_checkout(ctxi, lli);
+	if (unlikely(!rhte)) {
+		dev_dbg(dev, "%s: Too many opens ctxid=%lld\n",
+			__func__, ctxid);
+		rc = -EMFILE;	/* too many opens  */
+		goto err1;
+	}
+
+	rsrc_handle = (rhte - ctxi->rht_start);
+
+	rht_format1(rhte, lli->lun_id[sdev->channel], ctxi->rht_perms, port);
+
+	last_lba = gli->max_lba;
+	pphys->hdr.return_flags = 0;
+	pphys->last_lba = last_lba;
+	pphys->rsrc_handle = rsrc_handle;
+
+	rc = cxlflash_afu_sync(afu, ctxid, rsrc_handle, AFU_LW_SYNC);
+	if (unlikely(rc)) {
+		dev_dbg(dev, "%s: AFU sync failed rc=%d\n", __func__, rc);
+		goto err2;
+	}
+
+out:
+	if (likely(ctxi))
+		put_context(ctxi);
+	dev_dbg(dev, "%s: returning handle=%llu rc=%d llba=%llu\n",
+		__func__, rsrc_handle, rc, last_lba);
+	return rc;
+
+err2:
+	marshal_udir_to_rele(pphys, &rel);
+	_cxlflash_disk_release(sdev, ctxi, &rel);
+	goto out;
+err1:
+	cxlflash_lun_detach(gli);
+	goto out;
+}
+
+/**
+ * ioctl_common() - common IOCTL handler for driver
+ * @sdev:	SCSI device associated with LUN.
+ * @cmd:	IOCTL command.
+ *
+ * Handles common fencing operations that are valid for multiple ioctls. Always
+ * allow through ioctls that are cleanup oriented in nature, even when operating
+ * in a failed/terminating state.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int ioctl_common(struct scsi_device *sdev, unsigned int cmd)
+{
+	struct cxlflash_cfg *cfg = shost_priv(sdev->host);
+	struct device *dev = &cfg->dev->dev;
+	struct llun_info *lli = sdev->hostdata;
+	int rc = 0;
+
+	if (unlikely(!lli)) {
+		dev_dbg(dev, "%s: Unknown LUN\n", __func__);
+		rc = -EINVAL;
+		goto out;
+	}
+
+	rc = check_state(cfg);
+	if (unlikely(rc) && (cfg->state == STATE_FAILTERM)) {
+		switch (cmd) {
+		case DK_CXLFLASH_VLUN_RESIZE:
+		case DK_CXLFLASH_RELEASE:
+		case DK_CXLFLASH_DETACH:
+			dev_dbg(dev, "%s: Command override rc=%d\n",
+				__func__, rc);
+			rc = 0;
+			break;
+		}
+	}
+out:
+	return rc;
+}
+
+/**
+ * cxlflash_ioctl() - IOCTL handler for driver
+ * @sdev:	SCSI device associated with LUN.
+ * @cmd:	IOCTL command.
+ * @arg:	Userspace ioctl data structure.
+ *
+ * A read/write semaphore is used to implement a 'drain' of currently
+ * running ioctls. The read semaphore is taken at the beginning of each
+ * ioctl thread and released upon concluding execution. Additionally the
+ * semaphore should be released and then reacquired in any ioctl execution
+ * path which will wait for an event to occur that is outside the scope of
+ * the ioctl (i.e. an adapter reset). To drain the ioctls currently running,
+ * a thread simply needs to acquire the write semaphore.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+int cxlflash_ioctl(struct scsi_device *sdev, unsigned int cmd, void __user *arg)
+{
+	typedef int (*sioctl) (struct scsi_device *, void *);
+
+	struct cxlflash_cfg *cfg = shost_priv(sdev->host);
+	struct device *dev = &cfg->dev->dev;
+	struct afu *afu = cfg->afu;
+	struct dk_cxlflash_hdr *hdr;
+	char buf[sizeof(union cxlflash_ioctls)];
+	size_t size = 0;
+	bool known_ioctl = false;
+	int idx;
+	int rc = 0;
+	struct Scsi_Host *shost = sdev->host;
+	sioctl do_ioctl = NULL;
+
+	static const struct {
+		size_t size;
+		sioctl ioctl;
+	} ioctl_tbl[] = {	/* NOTE: order matters here */
+	{sizeof(struct dk_cxlflash_attach), (sioctl)cxlflash_disk_attach},
+	{sizeof(struct dk_cxlflash_udirect), cxlflash_disk_direct_open},
+	{sizeof(struct dk_cxlflash_release), (sioctl)cxlflash_disk_release},
+	{sizeof(struct dk_cxlflash_detach), (sioctl)cxlflash_disk_detach},
+	{sizeof(struct dk_cxlflash_verify), (sioctl)cxlflash_disk_verify},
+	{sizeof(struct dk_cxlflash_recover_afu), (sioctl)cxlflash_afu_recover},
+	{sizeof(struct dk_cxlflash_manage_lun), (sioctl)cxlflash_manage_lun},
+	{sizeof(struct dk_cxlflash_uvirtual), cxlflash_disk_virtual_open},
+	{sizeof(struct dk_cxlflash_resize), (sioctl)cxlflash_vlun_resize},
+	{sizeof(struct dk_cxlflash_clone), (sioctl)cxlflash_disk_clone},
+	};
+
+	/* Hold read semaphore so we can drain if needed */
+	down_read(&cfg->ioctl_rwsem);
+
+	/* Restrict command set to physical support only for internal LUN */
+	if (afu->internal_lun)
+		switch (cmd) {
+		case DK_CXLFLASH_RELEASE:
+		case DK_CXLFLASH_USER_VIRTUAL:
+		case DK_CXLFLASH_VLUN_RESIZE:
+		case DK_CXLFLASH_VLUN_CLONE:
+			dev_dbg(dev, "%s: %s not supported for lun_mode=%d\n",
+				__func__, decode_ioctl(cmd), afu->internal_lun);
+			rc = -EINVAL;
+			goto cxlflash_ioctl_exit;
+		}
+
+	switch (cmd) {
+	case DK_CXLFLASH_ATTACH:
+	case DK_CXLFLASH_USER_DIRECT:
+	case DK_CXLFLASH_RELEASE:
+	case DK_CXLFLASH_DETACH:
+	case DK_CXLFLASH_VERIFY:
+	case DK_CXLFLASH_RECOVER_AFU:
+	case DK_CXLFLASH_USER_VIRTUAL:
+	case DK_CXLFLASH_VLUN_RESIZE:
+	case DK_CXLFLASH_VLUN_CLONE:
+		dev_dbg(dev, "%s: %s (%08X) on dev(%d/%d/%d/%llu)\n",
+			__func__, decode_ioctl(cmd), cmd, shost->host_no,
+			sdev->channel, sdev->id, sdev->lun);
+		rc = ioctl_common(sdev, cmd);
+		if (unlikely(rc))
+			goto cxlflash_ioctl_exit;
+
+		fallthrough;
+
+	case DK_CXLFLASH_MANAGE_LUN:
+		known_ioctl = true;
+		idx = _IOC_NR(cmd) - _IOC_NR(DK_CXLFLASH_ATTACH);
+		size = ioctl_tbl[idx].size;
+		do_ioctl = ioctl_tbl[idx].ioctl;
+
+		if (likely(do_ioctl))
+			break;
+
+		fallthrough;
+	default:
+		rc = -EINVAL;
+		goto cxlflash_ioctl_exit;
+	}
+
+	if (unlikely(copy_from_user(&buf, arg, size))) {
+		dev_err(dev, "%s: copy_from_user() fail size=%lu cmd=%u (%s) arg=%p\n",
+			__func__, size, cmd, decode_ioctl(cmd), arg);
+		rc = -EFAULT;
+		goto cxlflash_ioctl_exit;
+	}
+
+	hdr = (struct dk_cxlflash_hdr *)&buf;
+	if (hdr->version != DK_CXLFLASH_VERSION_0) {
+		dev_dbg(dev, "%s: Version %u not supported for %s\n",
+			__func__, hdr->version, decode_ioctl(cmd));
+		rc = -EINVAL;
+		goto cxlflash_ioctl_exit;
+	}
+
+	if (hdr->rsvd[0] || hdr->rsvd[1] || hdr->rsvd[2] || hdr->return_flags) {
+		dev_dbg(dev, "%s: Reserved/rflags populated\n", __func__);
+		rc = -EINVAL;
+		goto cxlflash_ioctl_exit;
+	}
+
+	rc = do_ioctl(sdev, (void *)&buf);
+	if (likely(!rc))
+		if (unlikely(copy_to_user(arg, &buf, size))) {
+			dev_err(dev, "%s: copy_to_user() fail size=%lu cmd=%u (%s) arg=%p\n",
+				__func__, size, cmd, decode_ioctl(cmd), arg);
+			rc = -EFAULT;
+		}
+
+	/* fall through to exit */
+
+cxlflash_ioctl_exit:
+	up_read(&cfg->ioctl_rwsem);
+	if (unlikely(rc && known_ioctl))
+		dev_err(dev, "%s: ioctl %s (%08X) on dev(%d/%d/%d/%llu) "
+			"returned rc %d\n", __func__,
+			decode_ioctl(cmd), cmd, shost->host_no,
+			sdev->channel, sdev->id, sdev->lun, rc);
+	else
+		dev_dbg(dev, "%s: ioctl %s (%08X) on dev(%d/%d/%d/%llu) "
+			"returned rc %d\n", __func__, decode_ioctl(cmd),
+			cmd, shost->host_no, sdev->channel, sdev->id,
+			sdev->lun, rc);
+	return rc;
+}