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authorBart Van Assche <bart.vanassche@sandisk.com>2017-06-02 14:21:55 -0700
committerMartin K. Petersen <martin.petersen@oracle.com>2017-06-12 20:55:59 -0400
commit0db6ca8a5e1ea585795db3643ec7d50fc8cb1aff (patch)
tree52ae689dcddbc9155a840617c405de2b377de618 /drivers/scsi/scsi_scan.c
parent43f7571be077ee4673466cbcba115427d68440e1 (diff)
downloadlinux-0db6ca8a5e1ea585795db3643ec7d50fc8cb1aff.tar.bz2
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_scan.c')
-rw-r--r--drivers/scsi/scsi_scan.c16
1 files changed, 9 insertions, 7 deletions
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 6f7128f49c30..e6de4eee97a3 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -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)