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scsi: Protect SCSI device state changes with a mutex 

Serializing SCSI device state changes avoids that two state changes can
occur concurrently, e.g. the state changes in scsi_target_block() and
__scsi_remove_device(). This serialization is essential to make patch
"Make __scsi_remove_device go straight from BLOCKED to DEL" work
reliably.

Enable this mechanism for all scsi_target_*block() callers but not for
the scsi_internal_device_unblock() calls from the mpt3sas driver because
that driver can call scsi_internal_device_unblock() from atomic context.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Bart Van Assche 2017-06-02 14:21:55 -07:00 committed by Martin K. Petersen
parent 43f7571be0
commit 0db6ca8a5e
7 changed files with 66 additions and 24 deletions
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8
drivers/scsi/scsi_error.c
View File

@ -1628,11 +1628,17 @@ static void scsi_eh_offline_sdevs(struct list_head *work_q,
struct list_head *done_q)
{
struct scsi_cmnd *scmd, *next;
struct scsi_device *sdev;
list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
"not ready after error recovery\n");
scsi_device_set_state(scmd->device, SDEV_OFFLINE);
sdev = scmd->device;
mutex_lock(&sdev->state_mutex);
scsi_device_set_state(sdev, SDEV_OFFLINE);
mutex_unlock(&sdev->state_mutex);
scsi_eh_finish_cmd(scmd, done_q);
}
return;

27
drivers/scsi/scsi_lib.c
View File

@ -2882,7 +2882,12 @@ static void scsi_wait_for_queuecommand(struct scsi_device *sdev)
int
scsi_device_quiesce(struct scsi_device *sdev)
{
int err = scsi_device_set_state(sdev, SDEV_QUIESCE);
int err;
mutex_lock(&sdev->state_mutex);
err = scsi_device_set_state(sdev, SDEV_QUIESCE);
mutex_unlock(&sdev->state_mutex);
if (err)
return err;
@ -2910,10 +2915,11 @@ void scsi_device_resume(struct scsi_device *sdev)
* so assume the state is being managed elsewhere (for example
* device deleted during suspend)
*/
if (sdev->sdev_state != SDEV_QUIESCE ||
scsi_device_set_state(sdev, SDEV_RUNNING))
return;
scsi_run_queue(sdev->request_queue);
mutex_lock(&sdev->state_mutex);
if (sdev->sdev_state == SDEV_QUIESCE &&
scsi_device_set_state(sdev, SDEV_RUNNING) == 0)
scsi_run_queue(sdev->request_queue);
mutex_unlock(&sdev->state_mutex);
}
EXPORT_SYMBOL(scsi_device_resume);
@ -3012,6 +3018,7 @@ static int scsi_internal_device_block(struct scsi_device *sdev)
struct request_queue *q = sdev->request_queue;
int err;
mutex_lock(&sdev->state_mutex);
err = scsi_internal_device_block_nowait(sdev);
if (err == 0) {
if (q->mq_ops)
@ -3019,6 +3026,8 @@ static int scsi_internal_device_block(struct scsi_device *sdev)
else
scsi_wait_for_queuecommand(sdev);
}
mutex_unlock(&sdev->state_mutex);
return err;
}
@ -3089,7 +3098,13 @@ EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait);
static int scsi_internal_device_unblock(struct scsi_device *sdev,
enum scsi_device_state new_state)
{
return scsi_internal_device_unblock_nowait(sdev, new_state);
int ret;
mutex_lock(&sdev->state_mutex);
ret = scsi_internal_device_unblock_nowait(sdev, new_state);
mutex_unlock(&sdev->state_mutex);
return ret;
}
static void

16
drivers/scsi/scsi_scan.c
View File

@ -231,6 +231,7 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
sdev->id = starget->id;
sdev->lun = lun;
sdev->channel = starget->channel;
mutex_init(&sdev->state_mutex);
sdev->sdev_state = SDEV_CREATED;
INIT_LIST_HEAD(&sdev->siblings);
INIT_LIST_HEAD(&sdev->same_target_siblings);
@ -943,16 +944,17 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
/* set the device running here so that slave configure
* may do I/O */
mutex_lock(&sdev->state_mutex);
ret = scsi_device_set_state(sdev, SDEV_RUNNING);
if (ret) {
if (ret)
ret = scsi_device_set_state(sdev, SDEV_BLOCK);
mutex_unlock(&sdev->state_mutex);
if (ret) {
sdev_printk(KERN_ERR, sdev,
"in wrong state %s to complete scan\n",
scsi_device_state_name(sdev->sdev_state));
return SCSI_SCAN_NO_RESPONSE;
}
if (ret) {
sdev_printk(KERN_ERR, sdev,
"in wrong state %s to complete scan\n",
scsi_device_state_name(sdev->sdev_state));
return SCSI_SCAN_NO_RESPONSE;
}
if (*bflags & BLIST_MS_192_BYTES_FOR_3F)

24
drivers/scsi/scsi_sysfs.c
View File

@ -719,7 +719,7 @@ static ssize_t
store_state_field(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
int i;
int i, ret;
struct scsi_device *sdev = to_scsi_device(dev);
enum scsi_device_state state = 0;
@ -734,9 +734,11 @@ store_state_field(struct device *dev, struct device_attribute *attr,
if (!state)
return -EINVAL;
if (scsi_device_set_state(sdev, state))
return -EINVAL;
return count;
mutex_lock(&sdev->state_mutex);
ret = scsi_device_set_state(sdev, state);
mutex_unlock(&sdev->state_mutex);
return ret == 0 ? count : -EINVAL;
}
static ssize_t
@ -1272,6 +1274,7 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev)
void __scsi_remove_device(struct scsi_device *sdev)
{
struct device *dev = &sdev->sdev_gendev;
int res;
/*
* This cleanup path is not reentrant and while it is impossible
@ -1282,7 +1285,15 @@ void __scsi_remove_device(struct scsi_device *sdev)
return;
if (sdev->is_visible) {
if (scsi_device_set_state(sdev, SDEV_CANCEL) != 0)
/*
* If scsi_internal_target_block() is running concurrently,
* wait until it has finished before changing the device state.
*/
mutex_lock(&sdev->state_mutex);
res = scsi_device_set_state(sdev, SDEV_CANCEL);
mutex_unlock(&sdev->state_mutex);
if (res != 0)
return;
bsg_unregister_queue(sdev->request_queue);
@ -1298,7 +1309,10 @@ void __scsi_remove_device(struct scsi_device *sdev)
* scsi_run_queue() invocations have finished before tearing down the
* device.
*/
mutex_lock(&sdev->state_mutex);
scsi_device_set_state(sdev, SDEV_DEL);
mutex_unlock(&sdev->state_mutex);
blk_cleanup_queue(sdev->request_queue);
cancel_work_sync(&sdev->requeue_work);

7
drivers/scsi/scsi_transport_srp.c
View File

@ -554,11 +554,12 @@ int srp_reconnect_rport(struct srp_rport *rport)
* invoking scsi_target_unblock() won't change the state of
* these devices into running so do that explicitly.
*/
spin_lock_irq(shost->host_lock);
__shost_for_each_device(sdev, shost)
shost_for_each_device(sdev, shost) {
mutex_lock(&sdev->state_mutex);
if (sdev->sdev_state == SDEV_OFFLINE)
sdev->sdev_state = SDEV_RUNNING;
spin_unlock_irq(shost->host_lock);
mutex_unlock(&sdev->state_mutex);
}
} else if (rport->state == SRP_RPORT_RUNNING) {
/*
* srp_reconnect_rport() has been invoked with fast_io_fail

7
drivers/scsi/sd.c
View File

@ -1818,8 +1818,9 @@ static void sd_eh_reset(struct scsi_cmnd *scmd)
static int sd_eh_action(struct scsi_cmnd *scmd, int eh_disp)
{
struct scsi_disk *sdkp = scsi_disk(scmd->request->rq_disk);
struct scsi_device *sdev = scmd->device;
if (!scsi_device_online(scmd->device) ||
if (!scsi_device_online(sdev) ||
!scsi_medium_access_command(scmd) ||
host_byte(scmd->result) != DID_TIME_OUT ||
eh_disp != SUCCESS)
@ -1845,7 +1846,9 @@ static int sd_eh_action(struct scsi_cmnd *scmd, int eh_disp)
if (sdkp->medium_access_timed_out >= sdkp->max_medium_access_timeouts) {
scmd_printk(KERN_ERR, scmd,
"Medium access timeout failure. Offlining disk!\n");
scsi_device_set_state(scmd->device, SDEV_OFFLINE);
mutex_lock(&sdev->state_mutex);
scsi_device_set_state(sdev, SDEV_OFFLINE);
mutex_unlock(&sdev->state_mutex);
return SUCCESS;
}

1
include/scsi/scsi_device.h
View File

@ -207,6 +207,7 @@ struct scsi_device {
void *handler_data;
unsigned char access_state;
struct mutex state_mutex;
enum scsi_device_state sdev_state;
unsigned long sdev_data[0];
} __attribute__((aligned(sizeof(unsigned long))));