ata: libata-scsi: Fix ata_scsi_dev_rescan() error path

Commit 0c76106cb975 ("scsi: sd: Fix TCG OPAL unlock on system resume")
incorrectly handles failures of scsi_resume_device() in
ata_scsi_dev_rescan(), leading to a double call to
spin_unlock_irqrestore() to unlock a device port. Fix this by redefining
the goto labels used in case of errors and only unlock the port
scsi_scan_mutex when scsi_resume_device() fails.

Bug found with the Smatch static checker warning:

	drivers/ata/libata-scsi.c:4774 ata_scsi_dev_rescan()
	error: double unlocked 'ap->lock' (orig line 4757)

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Fixes: 0c76106cb975 ("scsi: sd: Fix TCG OPAL unlock on system resume")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 2f4c58837641077f3ad91974cd11affbe6dcd1e8..e954976891a9f502930a3a7ffc5f31df113d2326 100644 (file)
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -4745,7 +4745,7 @@ void ata_scsi_dev_rescan(struct work_struct *work)
                         * bail out.
                         */
                        if (ap->pflags & ATA_PFLAG_SUSPENDED)
-                               goto unlock;
+                               goto unlock_ap;
 
                        if (!sdev)
                                continue;
@@ -4758,7 +4758,7 @@ void ata_scsi_dev_rescan(struct work_struct *work)
                        if (do_resume) {
                                ret = scsi_resume_device(sdev);
                                if (ret == -EWOULDBLOCK)
-                                       goto unlock;
+                                       goto unlock_scan;
                                dev->flags &= ~ATA_DFLAG_RESUMING;
                        }
                        ret = scsi_rescan_device(sdev);
@@ -4766,12 +4766,13 @@ void ata_scsi_dev_rescan(struct work_struct *work)
                        spin_lock_irqsave(ap->lock, flags);
 
                        if (ret)
-                               goto unlock;
+                               goto unlock_ap;
                }
        }
 
-unlock:
+unlock_ap:
        spin_unlock_irqrestore(ap->lock, flags);
+unlock_scan:
        mutex_unlock(&ap->scsi_scan_mutex);
 
        /* Reschedule with a delay if scsi_rescan_device() returned an error */