275 lines
8.2 KiB
C
275 lines
8.2 KiB
C
// 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/kernfs.h>
|
|
#include <linux/sysfs.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/slab.h>
|
|
|
|
#include "zfcp_diag.h"
|
|
#include "zfcp_ext.h"
|
|
#include "zfcp_def.h"
|
|
|
|
/* Max age of data in a diagnostics buffer before it needs a refresh (in ms). */
|
|
#define ZFCP_DIAG_MAX_AGE (5 * 1000)
|
|
|
|
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)
|
|
{
|
|
/* set the timestamp so that the first test on age will always fail */
|
|
const unsigned long initial_timestamp =
|
|
jiffies - msecs_to_jiffies(ZFCP_DIAG_MAX_AGE);
|
|
struct zfcp_diag_adapter *diag;
|
|
struct zfcp_diag_header *hdr;
|
|
|
|
diag = kzalloc(sizeof(*diag), GFP_KERNEL);
|
|
if (diag == NULL)
|
|
return -ENOMEM;
|
|
|
|
/* 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);
|
|
hdr->timestamp = initial_timestamp;
|
|
|
|
/* 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);
|
|
hdr->timestamp = initial_timestamp;
|
|
|
|
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_sysfs_setup() - Setup the sysfs-group for adapter-diagnostics.
|
|
* @adapter: target adapter to which the group should be added.
|
|
*
|
|
* Return: 0 on success; Something else otherwise (see sysfs_create_group()).
|
|
*/
|
|
int zfcp_diag_sysfs_setup(struct zfcp_adapter *const adapter)
|
|
{
|
|
int rc = sysfs_create_group(&adapter->ccw_device->dev.kobj,
|
|
&zfcp_sysfs_diag_attr_group);
|
|
if (rc == 0)
|
|
adapter->diagnostics->sysfs_established = 1;
|
|
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* zfcp_diag_sysfs_destroy() - Remove the sysfs-group for adapter-diagnostics.
|
|
* @adapter: target adapter from which the group should be removed.
|
|
*/
|
|
void zfcp_diag_sysfs_destroy(struct zfcp_adapter *const adapter)
|
|
{
|
|
if (adapter->diagnostics == NULL ||
|
|
!adapter->diagnostics->sysfs_established)
|
|
return;
|
|
|
|
/*
|
|
* We need this state-handling so we can prevent warnings being printed
|
|
* on the kernel-console in case we have to abort a halfway done
|
|
* zfcp_adapter_enqueue(), in which the sysfs-group was not yet
|
|
* established. sysfs_remove_group() does this checking as well, but
|
|
* still prints a warning in case we try to remove a group that has not
|
|
* been established before
|
|
*/
|
|
adapter->diagnostics->sysfs_established = 0;
|
|
sysfs_remove_group(&adapter->ccw_device->dev.kobj,
|
|
&zfcp_sysfs_diag_attr_group);
|
|
}
|
|
|
|
|
|
/**
|
|
* 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;
|
|
}
|
|
|
|
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_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) >= ZFCP_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(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;
|
|
}
|