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scsi: Protect SCSI device state changes with a mutex

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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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7
drivers/scsi/sd.c
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@@ -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;
}