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