Adding upstream version 4.19.249.upstream/4.19.249upstream

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

1 files changed, 491 insertions, 0 deletions

diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h
new file mode 100644
index 000000000..1d3002d77
--- /dev/null
+++ b/drivers/block/xen-blkback/common.h
@@ -0,0 +1,491 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef __XEN_BLKIF__BACKEND__COMMON_H__
+#define __XEN_BLKIF__BACKEND__COMMON_H__
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/blkdev.h>
+#include <linux/vmalloc.h>
+#include <linux/wait.h>
+#include <linux/io.h>
+#include <linux/rbtree.h>
+#include <asm/setup.h>
+#include <asm/pgalloc.h>
+#include <asm/hypervisor.h>
+#include <xen/grant_table.h>
+#include <xen/page.h>
+#include <xen/xenbus.h>
+#include <xen/interface/io/ring.h>
+#include <xen/interface/io/blkif.h>
+#include <xen/interface/io/protocols.h>
+
+extern unsigned int xen_blkif_max_ring_order;
+extern unsigned int xenblk_max_queues;
+/*
+ * This is the maximum number of segments that would be allowed in indirect
+ * requests. This value will also be passed to the frontend.
+ */
+#define MAX_INDIRECT_SEGMENTS 256
+
+/*
+ * Xen use 4K pages. The guest may use different page size (4K or 64K)
+ * Number of Xen pages per segment
+ */
+#define XEN_PAGES_PER_SEGMENT   (PAGE_SIZE / XEN_PAGE_SIZE)
+
+#define XEN_PAGES_PER_INDIRECT_FRAME \
+	(XEN_PAGE_SIZE/sizeof(struct blkif_request_segment))
+#define SEGS_PER_INDIRECT_FRAME	\
+	(XEN_PAGES_PER_INDIRECT_FRAME / XEN_PAGES_PER_SEGMENT)
+
+#define MAX_INDIRECT_PAGES \
+	((MAX_INDIRECT_SEGMENTS + SEGS_PER_INDIRECT_FRAME - 1)/SEGS_PER_INDIRECT_FRAME)
+#define INDIRECT_PAGES(_segs) DIV_ROUND_UP(_segs, XEN_PAGES_PER_INDIRECT_FRAME)
+
+/* Not a real protocol.  Used to generate ring structs which contain
+ * the elements common to all protocols only.  This way we get a
+ * compiler-checkable way to use common struct elements, so we can
+ * avoid using switch(protocol) in a number of places.  */
+struct blkif_common_request {
+	char dummy;
+};
+
+/* i386 protocol version */
+
+struct blkif_x86_32_request_rw {
+	uint8_t        nr_segments;  /* number of segments                   */
+	blkif_vdev_t   handle;       /* only for read/write requests         */
+	uint64_t       id;           /* private guest value, echoed in resp  */
+	blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */
+	struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+} __attribute__((__packed__));
+
+struct blkif_x86_32_request_discard {
+	uint8_t        flag;         /* BLKIF_DISCARD_SECURE or zero         */
+	blkif_vdev_t   _pad1;        /* was "handle" for read/write requests */
+	uint64_t       id;           /* private guest value, echoed in resp  */
+	blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */
+	uint64_t       nr_sectors;
+} __attribute__((__packed__));
+
+struct blkif_x86_32_request_other {
+	uint8_t        _pad1;
+	blkif_vdev_t   _pad2;
+	uint64_t       id;           /* private guest value, echoed in resp  */
+} __attribute__((__packed__));
+
+struct blkif_x86_32_request_indirect {
+	uint8_t        indirect_op;
+	uint16_t       nr_segments;
+	uint64_t       id;
+	blkif_sector_t sector_number;
+	blkif_vdev_t   handle;
+	uint16_t       _pad1;
+	grant_ref_t    indirect_grefs[BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST];
+	/*
+	 * The maximum number of indirect segments (and pages) that will
+	 * be used is determined by MAX_INDIRECT_SEGMENTS, this value
+	 * is also exported to the guest (via xenstore
+	 * feature-max-indirect-segments entry), so the frontend knows how
+	 * many indirect segments the backend supports.
+	 */
+	uint64_t       _pad2;        /* make it 64 byte aligned */
+} __attribute__((__packed__));
+
+struct blkif_x86_32_request {
+	uint8_t        operation;    /* BLKIF_OP_???                         */
+	union {
+		struct blkif_x86_32_request_rw rw;
+		struct blkif_x86_32_request_discard discard;
+		struct blkif_x86_32_request_other other;
+		struct blkif_x86_32_request_indirect indirect;
+	} u;
+} __attribute__((__packed__));
+
+/* x86_64 protocol version */
+
+struct blkif_x86_64_request_rw {
+	uint8_t        nr_segments;  /* number of segments                   */
+	blkif_vdev_t   handle;       /* only for read/write requests         */
+	uint32_t       _pad1;        /* offsetof(blkif_reqest..,u.rw.id)==8  */
+	uint64_t       id;
+	blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */
+	struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+} __attribute__((__packed__));
+
+struct blkif_x86_64_request_discard {
+	uint8_t        flag;         /* BLKIF_DISCARD_SECURE or zero         */
+	blkif_vdev_t   _pad1;        /* was "handle" for read/write requests */
+        uint32_t       _pad2;        /* offsetof(blkif_..,u.discard.id)==8   */
+	uint64_t       id;
+	blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */
+	uint64_t       nr_sectors;
+} __attribute__((__packed__));
+
+struct blkif_x86_64_request_other {
+	uint8_t        _pad1;
+	blkif_vdev_t   _pad2;
+	uint32_t       _pad3;        /* offsetof(blkif_..,u.discard.id)==8   */
+	uint64_t       id;           /* private guest value, echoed in resp  */
+} __attribute__((__packed__));
+
+struct blkif_x86_64_request_indirect {
+	uint8_t        indirect_op;
+	uint16_t       nr_segments;
+	uint32_t       _pad1;        /* offsetof(blkif_..,u.indirect.id)==8   */
+	uint64_t       id;
+	blkif_sector_t sector_number;
+	blkif_vdev_t   handle;
+	uint16_t       _pad2;
+	grant_ref_t    indirect_grefs[BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST];
+	/*
+	 * The maximum number of indirect segments (and pages) that will
+	 * be used is determined by MAX_INDIRECT_SEGMENTS, this value
+	 * is also exported to the guest (via xenstore
+	 * feature-max-indirect-segments entry), so the frontend knows how
+	 * many indirect segments the backend supports.
+	 */
+	uint32_t       _pad3;        /* make it 64 byte aligned */
+} __attribute__((__packed__));
+
+struct blkif_x86_64_request {
+	uint8_t        operation;    /* BLKIF_OP_???                         */
+	union {
+		struct blkif_x86_64_request_rw rw;
+		struct blkif_x86_64_request_discard discard;
+		struct blkif_x86_64_request_other other;
+		struct blkif_x86_64_request_indirect indirect;
+	} u;
+} __attribute__((__packed__));
+
+DEFINE_RING_TYPES(blkif_common, struct blkif_common_request,
+		  struct blkif_response);
+DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request,
+		  struct blkif_response __packed);
+DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request,
+		  struct blkif_response);
+
+union blkif_back_rings {
+	struct blkif_back_ring        native;
+	struct blkif_common_back_ring common;
+	struct blkif_x86_32_back_ring x86_32;
+	struct blkif_x86_64_back_ring x86_64;
+};
+
+enum blkif_protocol {
+	BLKIF_PROTOCOL_NATIVE = 1,
+	BLKIF_PROTOCOL_X86_32 = 2,
+	BLKIF_PROTOCOL_X86_64 = 3,
+};
+
+/*
+ * Default protocol if the frontend doesn't specify one.
+ */
+#ifdef CONFIG_X86
+#  define BLKIF_PROTOCOL_DEFAULT BLKIF_PROTOCOL_X86_32
+#else
+#  define BLKIF_PROTOCOL_DEFAULT BLKIF_PROTOCOL_NATIVE
+#endif
+
+struct xen_vbd {
+	/* What the domain refers to this vbd as. */
+	blkif_vdev_t		handle;
+	/* Non-zero -> read-only */
+	unsigned char		readonly;
+	/* VDISK_xxx */
+	unsigned char		type;
+	/* phys device that this vbd maps to. */
+	u32			pdevice;
+	struct block_device	*bdev;
+	/* Cached size parameter. */
+	sector_t		size;
+	unsigned int		flush_support:1;
+	unsigned int		discard_secure:1;
+	unsigned int		feature_gnt_persistent:1;
+	unsigned int		overflow_max_grants:1;
+};
+
+struct backend_info;
+
+/* Number of requests that we can fit in a ring */
+#define XEN_BLKIF_REQS_PER_PAGE		32
+
+struct persistent_gnt {
+	struct page *page;
+	grant_ref_t gnt;
+	grant_handle_t handle;
+	unsigned long last_used;
+	bool active;
+	struct rb_node node;
+	struct list_head remove_node;
+};
+
+/* Per-ring information. */
+struct xen_blkif_ring {
+	/* Physical parameters of the comms window. */
+	unsigned int		irq;
+	union blkif_back_rings	blk_rings;
+	void			*blk_ring;
+	/* Private fields. */
+	spinlock_t		blk_ring_lock;
+
+	wait_queue_head_t	wq;
+	atomic_t		inflight;
+	bool			active;
+	/* One thread per blkif ring. */
+	struct task_struct	*xenblkd;
+	unsigned int		waiting_reqs;
+
+	/* List of all 'pending_req' available */
+	struct list_head	pending_free;
+	/* And its spinlock. */
+	spinlock_t		pending_free_lock;
+	wait_queue_head_t	pending_free_wq;
+
+	/* Tree to store persistent grants. */
+	struct rb_root		persistent_gnts;
+	unsigned int		persistent_gnt_c;
+	atomic_t		persistent_gnt_in_use;
+	unsigned long           next_lru;
+
+	/* Statistics. */
+	unsigned long		st_print;
+	unsigned long long	st_rd_req;
+	unsigned long long	st_wr_req;
+	unsigned long long	st_oo_req;
+	unsigned long long	st_f_req;
+	unsigned long long	st_ds_req;
+	unsigned long long	st_rd_sect;
+	unsigned long long	st_wr_sect;
+
+	/* Used by the kworker that offload work from the persistent purge. */
+	struct list_head	persistent_purge_list;
+	struct work_struct	persistent_purge_work;
+
+	/* Buffer of free pages to map grant refs. */
+	spinlock_t		free_pages_lock;
+	int			free_pages_num;
+	struct list_head	free_pages;
+
+	struct work_struct	free_work;
+	/* Thread shutdown wait queue. */
+	wait_queue_head_t	shutdown_wq;
+	struct xen_blkif 	*blkif;
+};
+
+struct xen_blkif {
+	/* Unique identifier for this interface. */
+	domid_t			domid;
+	unsigned int		handle;
+	/* Comms information. */
+	enum blkif_protocol	blk_protocol;
+	/* The VBD attached to this interface. */
+	struct xen_vbd		vbd;
+	/* Back pointer to the backend_info. */
+	struct backend_info	*be;
+	atomic_t		refcnt;
+	/* for barrier (drain) requests */
+	struct completion	drain_complete;
+	atomic_t		drain;
+
+	struct work_struct	free_work;
+	unsigned int 		nr_ring_pages;
+	/* All rings for this device. */
+	struct xen_blkif_ring	*rings;
+	unsigned int		nr_rings;
+};
+
+struct seg_buf {
+	unsigned long offset;
+	unsigned int nsec;
+};
+
+struct grant_page {
+	struct page 		*page;
+	struct persistent_gnt	*persistent_gnt;
+	grant_handle_t		handle;
+	grant_ref_t		gref;
+};
+
+/*
+ * Each outstanding request that we've passed to the lower device layers has a
+ * 'pending_req' allocated to it. Each buffer_head that completes decrements
+ * the pendcnt towards zero. When it hits zero, the specified domain has a
+ * response queued for it, with the saved 'id' passed back.
+ */
+struct pending_req {
+	struct xen_blkif_ring   *ring;
+	u64			id;
+	int			nr_segs;
+	atomic_t		pendcnt;
+	unsigned short		operation;
+	int			status;
+	struct list_head	free_list;
+	struct grant_page	*segments[MAX_INDIRECT_SEGMENTS];
+	/* Indirect descriptors */
+	struct grant_page	*indirect_pages[MAX_INDIRECT_PAGES];
+	struct seg_buf		seg[MAX_INDIRECT_SEGMENTS];
+	struct bio		*biolist[MAX_INDIRECT_SEGMENTS];
+	struct gnttab_unmap_grant_ref unmap[MAX_INDIRECT_SEGMENTS];
+	struct page                   *unmap_pages[MAX_INDIRECT_SEGMENTS];
+	struct gntab_unmap_queue_data gnttab_unmap_data;
+};
+
+
+#define vbd_sz(_v)	((_v)->bdev->bd_part ? \
+			 (_v)->bdev->bd_part->nr_sects : \
+			  get_capacity((_v)->bdev->bd_disk))
+
+#define xen_blkif_get(_b) (atomic_inc(&(_b)->refcnt))
+#define xen_blkif_put(_b)				\
+	do {						\
+		if (atomic_dec_and_test(&(_b)->refcnt))	\
+			schedule_work(&(_b)->free_work);\
+	} while (0)
+
+struct phys_req {
+	unsigned short		dev;
+	blkif_sector_t		nr_sects;
+	struct block_device	*bdev;
+	blkif_sector_t		sector_number;
+};
+int xen_blkif_interface_init(void);
+
+int xen_blkif_xenbus_init(void);
+
+irqreturn_t xen_blkif_be_int(int irq, void *dev_id);
+int xen_blkif_schedule(void *arg);
+int xen_blkif_purge_persistent(void *arg);
+void xen_blkbk_free_caches(struct xen_blkif_ring *ring);
+
+int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt,
+			      struct backend_info *be, int state);
+
+int xen_blkbk_barrier(struct xenbus_transaction xbt,
+		      struct backend_info *be, int state);
+struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be);
+void xen_blkbk_unmap_purged_grants(struct work_struct *work);
+
+static inline void blkif_get_x86_32_req(struct blkif_request *dst,
+					struct blkif_x86_32_request *src)
+{
+	int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST, j;
+	dst->operation = READ_ONCE(src->operation);
+	switch (dst->operation) {
+	case BLKIF_OP_READ:
+	case BLKIF_OP_WRITE:
+	case BLKIF_OP_WRITE_BARRIER:
+	case BLKIF_OP_FLUSH_DISKCACHE:
+		dst->u.rw.nr_segments = src->u.rw.nr_segments;
+		dst->u.rw.handle = src->u.rw.handle;
+		dst->u.rw.id = src->u.rw.id;
+		dst->u.rw.sector_number = src->u.rw.sector_number;
+		barrier();
+		if (n > dst->u.rw.nr_segments)
+			n = dst->u.rw.nr_segments;
+		for (i = 0; i < n; i++)
+			dst->u.rw.seg[i] = src->u.rw.seg[i];
+		break;
+	case BLKIF_OP_DISCARD:
+		dst->u.discard.flag = src->u.discard.flag;
+		dst->u.discard.id = src->u.discard.id;
+		dst->u.discard.sector_number = src->u.discard.sector_number;
+		dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
+		break;
+	case BLKIF_OP_INDIRECT:
+		dst->u.indirect.indirect_op = src->u.indirect.indirect_op;
+		dst->u.indirect.nr_segments = src->u.indirect.nr_segments;
+		dst->u.indirect.handle = src->u.indirect.handle;
+		dst->u.indirect.id = src->u.indirect.id;
+		dst->u.indirect.sector_number = src->u.indirect.sector_number;
+		barrier();
+		j = min(MAX_INDIRECT_PAGES, INDIRECT_PAGES(dst->u.indirect.nr_segments));
+		for (i = 0; i < j; i++)
+			dst->u.indirect.indirect_grefs[i] =
+				src->u.indirect.indirect_grefs[i];
+		break;
+	default:
+		/*
+		 * Don't know how to translate this op. Only get the
+		 * ID so failure can be reported to the frontend.
+		 */
+		dst->u.other.id = src->u.other.id;
+		break;
+	}
+}
+
+static inline void blkif_get_x86_64_req(struct blkif_request *dst,
+					struct blkif_x86_64_request *src)
+{
+	int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST, j;
+	dst->operation = READ_ONCE(src->operation);
+	switch (dst->operation) {
+	case BLKIF_OP_READ:
+	case BLKIF_OP_WRITE:
+	case BLKIF_OP_WRITE_BARRIER:
+	case BLKIF_OP_FLUSH_DISKCACHE:
+		dst->u.rw.nr_segments = src->u.rw.nr_segments;
+		dst->u.rw.handle = src->u.rw.handle;
+		dst->u.rw.id = src->u.rw.id;
+		dst->u.rw.sector_number = src->u.rw.sector_number;
+		barrier();
+		if (n > dst->u.rw.nr_segments)
+			n = dst->u.rw.nr_segments;
+		for (i = 0; i < n; i++)
+			dst->u.rw.seg[i] = src->u.rw.seg[i];
+		break;
+	case BLKIF_OP_DISCARD:
+		dst->u.discard.flag = src->u.discard.flag;
+		dst->u.discard.id = src->u.discard.id;
+		dst->u.discard.sector_number = src->u.discard.sector_number;
+		dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
+		break;
+	case BLKIF_OP_INDIRECT:
+		dst->u.indirect.indirect_op = src->u.indirect.indirect_op;
+		dst->u.indirect.nr_segments = src->u.indirect.nr_segments;
+		dst->u.indirect.handle = src->u.indirect.handle;
+		dst->u.indirect.id = src->u.indirect.id;
+		dst->u.indirect.sector_number = src->u.indirect.sector_number;
+		barrier();
+		j = min(MAX_INDIRECT_PAGES, INDIRECT_PAGES(dst->u.indirect.nr_segments));
+		for (i = 0; i < j; i++)
+			dst->u.indirect.indirect_grefs[i] =
+				src->u.indirect.indirect_grefs[i];
+		break;
+	default:
+		/*
+		 * Don't know how to translate this op. Only get the
+		 * ID so failure can be reported to the frontend.
+		 */
+		dst->u.other.id = src->u.other.id;
+		break;
+	}
+}
+
+#endif /* __XEN_BLKIF__BACKEND__COMMON_H__ */