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Commit a817e73f authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Revert "scsi: make 'state' device attribute pollable" 



This reverts commit 8a97712e.

This commit added a call to sysfs_notify() from within
scsi_device_set_state(), which in turn turns out to make libata very
unhappy, because ata_eh_detach_dev() does

        spin_lock_irqsave(ap->lock, flags);
        ..
        if (ata_scsi_offline_dev(dev)) {
                dev->flags |= ATA_DFLAG_DETACHED;
                ap->pflags |= ATA_PFLAG_SCSI_HOTPLUG;
        }

and ata_scsi_offline_dev() then does that scsi_device_set_state() to set
it offline.

So now we called sysfs_notify() from within a spinlocked region, which
really doesn't work.  The 0day robot reported this as:

   BUG: sleeping function called from invalid context at kernel/locking/mutex.c:238

because sysfs_notify() ends up calling kernfs_find_and_get_ns() which
then does mutex_lock(&kernfs_mutex)..

The pollability of the device state isn't critical, so revert this all
for now, and maybe we'll do it differently in the future.

Reported-by: default avatarFengguang Wu <fengguang.wu@intel.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Acked-by: default avatarHannes Reinecke <hare@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e4880bc5

drivers/scsi/scsi_lib.c

+0 −3
Original line number Diff line number Diff line
@@ -2685,7 +2685,6 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) 


	}

	sdev->sdev_state = state;

	sysfs_notify(&sdev->sdev_gendev.kobj, NULL, "state");

	return 0;



 illegal:
@@ -3109,7 +3108,6 @@ int scsi_internal_device_unblock_nowait(struct scsi_device *sdev, 
	case SDEV_BLOCK:

	case SDEV_TRANSPORT_OFFLINE:

		sdev->sdev_state = new_state;

		sysfs_notify(&sdev->sdev_gendev.kobj, NULL, "state");

		break;

	case SDEV_CREATED_BLOCK:

		if (new_state == SDEV_TRANSPORT_OFFLINE ||
@@ -3117,7 +3115,6 @@ int scsi_internal_device_unblock_nowait(struct scsi_device *sdev, 
			sdev->sdev_state = new_state;

		else

			sdev->sdev_state = SDEV_CREATED;

		sysfs_notify(&sdev->sdev_gendev.kobj, NULL, "state");

		break;

	case SDEV_CANCEL:

	case SDEV_OFFLINE:

drivers/scsi/scsi_transport_srp.c

+1 −4
Original line number Diff line number Diff line
@@ -556,11 +556,8 @@ int srp_reconnect_rport(struct srp_rport *rport) 
		 */

		shost_for_each_device(sdev, shost) {

			mutex_lock(&sdev->state_mutex);

			if (sdev->sdev_state == SDEV_OFFLINE) {

			if (sdev->sdev_state == SDEV_OFFLINE)

				sdev->sdev_state = SDEV_RUNNING;

				sysfs_notify(&sdev->sdev_gendev.kobj,

					     NULL, "state");

			}

			mutex_unlock(&sdev->state_mutex);

		}

	} else if (rport->state == SRP_RPORT_RUNNING) {