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scsi: cxlflash: Schedule asynchronous reset of the host 

A context reset failure indicates the AFU is in a bad state. At present,
when such a situation occurs, no further action is taken. This leaves the
adapter in an unusable state with no recoverable actions.

To avoid this situation, context reset failures will be escalated to a host
reset operation. This will be done asynchronously to allow the acting
thread to return to the user with a failure.

Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Acked-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Uma Krishnan 2017-06-21 21:14:17 -05:00 committed by Martin K. Petersen
parent a96851d337
commit 0b09e71118
2 changed files with 104 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/scsi/cxlflash/common.h
View File

@ -15,6 +15,7 @@
#ifndef _CXLFLASH_COMMON_H
#define _CXLFLASH_COMMON_H
#include <linux/async.h>
#include <linux/irq_poll.h>
#include <linux/list.h>
#include <linux/rwsem.h>
@ -144,6 +145,7 @@ struct cxlflash_cfg {
bool tmf_active;
wait_queue_head_t reset_waitq;
enum cxlflash_state state;
async_cookie_t async_reset_cookie;
};
struct afu_cmd {

137
drivers/scsi/cxlflash/main.c
View File

@ -585,6 +585,20 @@ static void free_mem(struct cxlflash_cfg *cfg)
}
}
/**
* cxlflash_reset_sync() - synchronizing point for asynchronous resets
* @cfg: Internal structure associated with the host.
*/
static void cxlflash_reset_sync(struct cxlflash_cfg *cfg)
{
if (cfg->async_reset_cookie == 0)
return;
/* Wait until all async calls prior to this cookie have completed */
async_synchronize_cookie(cfg->async_reset_cookie + 1);
cfg->async_reset_cookie = 0;
}
/**
* stop_afu() - stops the AFU command timers and unmaps the MMIO space
* @cfg: Internal structure associated with the host.
@ -601,6 +615,8 @@ static void stop_afu(struct cxlflash_cfg *cfg)
int i;
cancel_work_sync(&cfg->work_q);
if (!current_is_async())
cxlflash_reset_sync(cfg);
if (likely(afu)) {
while (atomic_read(&afu->cmds_active))
@ -2004,6 +2020,91 @@ err1:
goto out;
}
/**
* afu_reset() - resets the AFU
* @cfg: Internal structure associated with the host.
*
* Return: 0 on success, -errno on failure
*/
static int afu_reset(struct cxlflash_cfg *cfg)
{
struct device *dev = &cfg->dev->dev;
int rc = 0;
/* Stop the context before the reset. Since the context is
* no longer available restart it after the reset is complete
*/
term_afu(cfg);
rc = init_afu(cfg);
dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
return rc;
}
/**
* drain_ioctls() - wait until all currently executing ioctls have completed
* @cfg: Internal structure associated with the host.
*
* Obtain write access to read/write semaphore that wraps ioctl
* handling to 'drain' ioctls currently executing.
*/
static void drain_ioctls(struct cxlflash_cfg *cfg)
{
down_write(&cfg->ioctl_rwsem);
up_write(&cfg->ioctl_rwsem);
}
/**
* cxlflash_async_reset_host() - asynchronous host reset handler
* @data: Private data provided while scheduling reset.
* @cookie: Cookie that can be used for checkpointing.
*/
static void cxlflash_async_reset_host(void *data, async_cookie_t cookie)
{
struct cxlflash_cfg *cfg = data;
struct device *dev = &cfg->dev->dev;
int rc = 0;
if (cfg->state != STATE_RESET) {
dev_dbg(dev, "%s: Not performing a reset, state=%d\n",
__func__, cfg->state);
goto out;
}
drain_ioctls(cfg);
cxlflash_mark_contexts_error(cfg);
rc = afu_reset(cfg);
if (rc)
cfg->state = STATE_FAILTERM;
else
cfg->state = STATE_NORMAL;
wake_up_all(&cfg->reset_waitq);
out:
scsi_unblock_requests(cfg->host);
}
/**
* cxlflash_schedule_async_reset() - schedule an asynchronous host reset
* @cfg: Internal structure associated with the host.
*/
static void cxlflash_schedule_async_reset(struct cxlflash_cfg *cfg)
{
struct device *dev = &cfg->dev->dev;
if (cfg->state != STATE_NORMAL) {
dev_dbg(dev, "%s: Not performing reset state=%d\n",
__func__, cfg->state);
return;
}
cfg->state = STATE_RESET;
scsi_block_requests(cfg->host);
cfg->async_reset_cookie = async_schedule(cxlflash_async_reset_host,
cfg);
}
/**
* cxlflash_afu_sync() - builds and sends an AFU sync command
* @afu: AFU associated with the host.
@ -2085,6 +2186,7 @@ retry:
rc = afu->context_reset(hwq);
if (!rc && ++nretry < 2)
goto retry;
cxlflash_schedule_async_reset(cfg);
}
out:
@ -2095,41 +2197,6 @@ out:
return rc;
}
/**
* afu_reset() - resets the AFU
* @cfg: Internal structure associated with the host.
*
* Return: 0 on success, -errno on failure
*/
static int afu_reset(struct cxlflash_cfg *cfg)
{
struct device *dev = &cfg->dev->dev;
int rc = 0;
/* Stop the context before the reset. Since the context is
* no longer available restart it after the reset is complete
*/
term_afu(cfg);
rc = init_afu(cfg);
dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
return rc;
}
/**
* drain_ioctls() - wait until all currently executing ioctls have completed
* @cfg: Internal structure associated with the host.
*
* Obtain write access to read/write semaphore that wraps ioctl
* handling to 'drain' ioctls currently executing.
*/
static void drain_ioctls(struct cxlflash_cfg *cfg)
{
down_write(&cfg->ioctl_rwsem);
up_write(&cfg->ioctl_rwsem);
}
/**
* cxlflash_eh_device_reset_handler() - reset a single LUN
* @scp: SCSI command to send.