diff options
| author | Bart Van Assche <bart.vanassche@sandisk.com> | 2017-06-03 00:21:55 +0300 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2017-06-13 03:55:59 +0300 |
| commit | 0db6ca8a5e1ea585795db3643ec7d50fc8cb1aff (patch) | |
| tree | 52ae689dcddbc9155a840617c405de2b377de618 /drivers/scsi/scsi_sysfs.c | |
| parent | 43f7571be077ee4673466cbcba115427d68440e1 (diff) | |
| download | linux-0db6ca8a5e1ea585795db3643ec7d50fc8cb1aff.tar.xz | |
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>
Diffstat (limited to 'drivers/scsi/scsi_sysfs.c')
| -rw-r--r-- | drivers/scsi/scsi_sysfs.c | 24 |
1 files changed, 19 insertions, 5 deletions
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index 82dfe07b1d47..a91537a3abbf 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -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); |