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path: root/drivers/s390/scsi/zfcp_diag.c
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-rw-r--r--drivers/s390/scsi/zfcp_diag.c263
1 files changed, 263 insertions, 0 deletions
diff --git a/drivers/s390/scsi/zfcp_diag.c b/drivers/s390/scsi/zfcp_diag.c
new file mode 100644
index 000000000..4d2d89d9c
--- /dev/null
+++ b/drivers/s390/scsi/zfcp_diag.c
@@ -0,0 +1,263 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * zfcp device driver
+ *
+ * Functions to handle diagnostics.
+ *
+ * Copyright IBM Corp. 2018
+ */
+
+#include <linux/spinlock.h>
+#include <linux/jiffies.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+
+#include "zfcp_diag.h"
+#include "zfcp_ext.h"
+#include "zfcp_def.h"
+
+static DECLARE_WAIT_QUEUE_HEAD(__zfcp_diag_publish_wait);
+
+/**
+ * zfcp_diag_adapter_setup() - Setup storage for adapter diagnostics.
+ * @adapter: the adapter to setup diagnostics for.
+ *
+ * Creates the data-structures to store the diagnostics for an adapter. This
+ * overwrites whatever was stored before at &zfcp_adapter->diagnostics!
+ *
+ * Return:
+ * * 0 - Everyting is OK
+ * * -ENOMEM - Could not allocate all/parts of the data-structures;
+ * &zfcp_adapter->diagnostics remains unchanged
+ */
+int zfcp_diag_adapter_setup(struct zfcp_adapter *const adapter)
+{
+ struct zfcp_diag_adapter *diag;
+ struct zfcp_diag_header *hdr;
+
+ diag = kzalloc(sizeof(*diag), GFP_KERNEL);
+ if (diag == NULL)
+ return -ENOMEM;
+
+ diag->max_age = (5 * 1000); /* default value: 5 s */
+
+ /* setup header for port_data */
+ hdr = &diag->port_data.header;
+
+ spin_lock_init(&hdr->access_lock);
+ hdr->buffer = &diag->port_data.data;
+ hdr->buffer_size = sizeof(diag->port_data.data);
+ /* set the timestamp so that the first test on age will always fail */
+ hdr->timestamp = jiffies - msecs_to_jiffies(diag->max_age);
+
+ /* setup header for config_data */
+ hdr = &diag->config_data.header;
+
+ spin_lock_init(&hdr->access_lock);
+ hdr->buffer = &diag->config_data.data;
+ hdr->buffer_size = sizeof(diag->config_data.data);
+ /* set the timestamp so that the first test on age will always fail */
+ hdr->timestamp = jiffies - msecs_to_jiffies(diag->max_age);
+
+ adapter->diagnostics = diag;
+ return 0;
+}
+
+/**
+ * zfcp_diag_adapter_free() - Frees all adapter diagnostics allocations.
+ * @adapter: the adapter whose diagnostic structures should be freed.
+ *
+ * Frees all data-structures in the given adapter that store diagnostics
+ * information. Can savely be called with partially setup diagnostics.
+ */
+void zfcp_diag_adapter_free(struct zfcp_adapter *const adapter)
+{
+ kfree(adapter->diagnostics);
+ adapter->diagnostics = NULL;
+}
+
+/**
+ * zfcp_diag_update_xdata() - Update a diagnostics buffer.
+ * @hdr: the meta data to update.
+ * @data: data to use for the update.
+ * @incomplete: flag stating whether the data in @data is incomplete.
+ */
+void zfcp_diag_update_xdata(struct zfcp_diag_header *const hdr,
+ const void *const data, const bool incomplete)
+{
+ const unsigned long capture_timestamp = jiffies;
+ unsigned long flags;
+
+ spin_lock_irqsave(&hdr->access_lock, flags);
+
+ /* make sure we never go into the past with an update */
+ if (!time_after_eq(capture_timestamp, hdr->timestamp))
+ goto out;
+
+ hdr->timestamp = capture_timestamp;
+ hdr->incomplete = incomplete;
+ memcpy(hdr->buffer, data, hdr->buffer_size);
+out:
+ spin_unlock_irqrestore(&hdr->access_lock, flags);
+}
+
+/**
+ * zfcp_diag_update_port_data_buffer() - Implementation of
+ * &typedef zfcp_diag_update_buffer_func
+ * to collect and update Port Data.
+ * @adapter: Adapter to collect Port Data from.
+ *
+ * This call is SYNCHRONOUS ! It blocks till the respective command has
+ * finished completely, or has failed in some way.
+ *
+ * Return:
+ * * 0 - Successfully retrieved new Diagnostics and Updated the buffer;
+ * this also includes cases where data was retrieved, but
+ * incomplete; you'll have to check the flag ``incomplete``
+ * of &struct zfcp_diag_header.
+ * * see zfcp_fsf_exchange_port_data_sync() for possible error-codes (
+ * excluding -EAGAIN)
+ */
+int zfcp_diag_update_port_data_buffer(struct zfcp_adapter *const adapter)
+{
+ int rc;
+
+ rc = zfcp_fsf_exchange_port_data_sync(adapter->qdio, NULL);
+ if (rc == -EAGAIN)
+ rc = 0; /* signaling incomplete via struct zfcp_diag_header */
+
+ /* buffer-data was updated in zfcp_fsf_exchange_port_data_handler() */
+
+ return rc;
+}
+
+/**
+ * zfcp_diag_update_config_data_buffer() - Implementation of
+ * &typedef zfcp_diag_update_buffer_func
+ * to collect and update Config Data.
+ * @adapter: Adapter to collect Config Data from.
+ *
+ * This call is SYNCHRONOUS ! It blocks till the respective command has
+ * finished completely, or has failed in some way.
+ *
+ * Return:
+ * * 0 - Successfully retrieved new Diagnostics and Updated the buffer;
+ * this also includes cases where data was retrieved, but
+ * incomplete; you'll have to check the flag ``incomplete``
+ * of &struct zfcp_diag_header.
+ * * see zfcp_fsf_exchange_config_data_sync() for possible error-codes (
+ * excluding -EAGAIN)
+ */
+int zfcp_diag_update_config_data_buffer(struct zfcp_adapter *const adapter)
+{
+ int rc;
+
+ rc = zfcp_fsf_exchange_config_data_sync(adapter->qdio, NULL);
+ if (rc == -EAGAIN)
+ rc = 0; /* signaling incomplete via struct zfcp_diag_header */
+
+ /* buffer-data was updated in zfcp_fsf_exchange_config_data_handler() */
+
+ return rc;
+}
+
+static int __zfcp_diag_update_buffer(struct zfcp_adapter *const adapter,
+ struct zfcp_diag_header *const hdr,
+ zfcp_diag_update_buffer_func buffer_update,
+ unsigned long *const flags)
+ __must_hold(hdr->access_lock)
+{
+ int rc;
+
+ if (hdr->updating == 1) {
+ rc = wait_event_interruptible_lock_irq(__zfcp_diag_publish_wait,
+ hdr->updating == 0,
+ hdr->access_lock);
+ rc = (rc == 0 ? -EAGAIN : -EINTR);
+ } else {
+ hdr->updating = 1;
+ spin_unlock_irqrestore(&hdr->access_lock, *flags);
+
+ /* unlocked, because update function sleeps */
+ rc = buffer_update(adapter);
+
+ spin_lock_irqsave(&hdr->access_lock, *flags);
+ hdr->updating = 0;
+
+ /*
+ * every thread waiting here went via an interruptible wait,
+ * so its fine to only wake those
+ */
+ wake_up_interruptible_all(&__zfcp_diag_publish_wait);
+ }
+
+ return rc;
+}
+
+static bool
+__zfcp_diag_test_buffer_age_isfresh(const struct zfcp_diag_adapter *const diag,
+ const struct zfcp_diag_header *const hdr)
+ __must_hold(hdr->access_lock)
+{
+ const unsigned long now = jiffies;
+
+ /*
+ * Should not happen (data is from the future).. if it does, still
+ * signal that it needs refresh
+ */
+ if (!time_after_eq(now, hdr->timestamp))
+ return false;
+
+ if (jiffies_to_msecs(now - hdr->timestamp) >= diag->max_age)
+ return false;
+
+ return true;
+}
+
+/**
+ * zfcp_diag_update_buffer_limited() - Collect diagnostics and update a
+ * diagnostics buffer rate limited.
+ * @adapter: Adapter to collect the diagnostics from.
+ * @hdr: buffer-header for which to update with the collected diagnostics.
+ * @buffer_update: Specific implementation for collecting and updating.
+ *
+ * This function will cause an update of the given @hdr by calling the also
+ * given @buffer_update function. If called by multiple sources at the same
+ * time, it will synchornize the update by only allowing one source to call
+ * @buffer_update and the others to wait for that source to complete instead
+ * (the wait is interruptible).
+ *
+ * Additionally this version is rate-limited and will only exit if either the
+ * buffer is fresh enough (within the limit) - it will do nothing if the buffer
+ * is fresh enough to begin with -, or if the source/thread that started this
+ * update is the one that made the update (to prevent endless loops).
+ *
+ * Return:
+ * * 0 - If the update was successfully published and/or the buffer is
+ * fresh enough
+ * * -EINTR - If the thread went into the wait-state and was interrupted
+ * * whatever @buffer_update returns
+ */
+int zfcp_diag_update_buffer_limited(struct zfcp_adapter *const adapter,
+ struct zfcp_diag_header *const hdr,
+ zfcp_diag_update_buffer_func buffer_update)
+{
+ unsigned long flags;
+ int rc;
+
+ spin_lock_irqsave(&hdr->access_lock, flags);
+
+ for (rc = 0;
+ !__zfcp_diag_test_buffer_age_isfresh(adapter->diagnostics, hdr);
+ rc = 0) {
+ rc = __zfcp_diag_update_buffer(adapter, hdr, buffer_update,
+ &flags);
+ if (rc != -EAGAIN)
+ break;
+ }
+
+ spin_unlock_irqrestore(&hdr->access_lock, flags);
+
+ return rc;
+}