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// 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)
/**
* 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);
}
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