diff mbox

[v2,06/12] Make __scsi_remove_device go straight from BLOCKED to DEL

Message ID 20170601232711.29062-7-bart.vanassche@sandisk.com (mailing list archive)
State Superseded, archived
Headers show

Commit Message

Bart Van Assche June 1, 2017, 11:27 p.m. UTC 
If a device is blocked, make __scsi_remove_device() cause it to
transition to the DEL state. This means that all the commands
issued in .shutdown() will error in the mid-layer, thus making
the removal proceed without being stopped.

This patch is a slightly modified version of a patch from James
Bottomley. This patch avoids that the following lockup occurs:

Call Trace:
 schedule+0x35/0x80
 schedule_timeout+0x237/0x2d0
 io_schedule_timeout+0xa6/0x110
 wait_for_completion_io+0xa3/0x110
 blk_execute_rq+0xdf/0x120
 scsi_execute+0xce/0x150 [scsi_mod]
 scsi_execute_req_flags+0x8f/0xf0 [scsi_mod]
 sd_sync_cache+0xa9/0x190 [sd_mod]
 sd_shutdown+0x6a/0x100 [sd_mod]
 sd_remove+0x64/0xc0 [sd_mod]
 __device_release_driver+0x8d/0x120
 device_release_driver+0x1e/0x30
 bus_remove_device+0xf9/0x170
 device_del+0x127/0x240
 __scsi_remove_device+0xc1/0xd0 [scsi_mod]
 scsi_forget_host+0x57/0x60 [scsi_mod]
 scsi_remove_host+0x72/0x110 [scsi_mod]
 srp_remove_work+0x8b/0x200 [ib_srp]

Reported-by: Israel Rukshin <israelr@mellanox.com>
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Israel Rukshin <israelr@mellanox.com>
Cc: Max Gurtovoy <maxg@mellanox.com>
Cc: Benjamin Block <bblock@linux.vnet.ibm.com>
---
 drivers/scsi/scsi_lib.c   |  2 +-
 drivers/scsi/scsi_sysfs.c | 13 +++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

Comments

Christoph Hellwig June 2, 2017, 7:18 a.m. UTC | #1 
On Thu, Jun 01, 2017 at 04:27:05PM -0700, Bart Van Assche wrote:
> If a device is blocked, make __scsi_remove_device() cause it to
> transition to the DEL state. This means that all the commands
> issued in .shutdown() will error in the mid-layer, thus making
> the removal proceed without being stopped.
> 
> This patch is a slightly modified version of a patch from James
> Bottomley. This patch avoids that the following lockup occurs:

Do we really need the printk for this case?  And if we do we should
probably rate limit it.
Bart Van Assche June 2, 2017, 8:58 p.m. UTC | #2 
On Fri, 2017-06-02 at 09:18 +0200, Christoph Hellwig wrote:
> On Thu, Jun 01, 2017 at 04:27:05PM -0700, Bart Van Assche wrote:
> > If a device is blocked, make __scsi_remove_device() cause it to
> > transition to the DEL state. This means that all the commands
> > issued in .shutdown() will error in the mid-layer, thus making
> > the removal proceed without being stopped.
> > 
> > This patch is a slightly modified version of a patch from James
> > Bottomley. This patch avoids that the following lockup occurs:
> 
> Do we really need the printk for this case?  And if we do we should
> probably rate limit it.

Hello Christoph,

The printk statement was useful during debugging to confirm that the
code path with the printk was hit. I will remove the printk.

Bart.
diff mbox

Patch

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 6a58a124714f..8665eccd2fc8 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2624,7 +2624,6 @@  scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
 		case SDEV_QUIESCE:
 		case SDEV_OFFLINE:
 		case SDEV_TRANSPORT_OFFLINE:
-		case SDEV_BLOCK:
 			break;
 		default:
 			goto illegal;
@@ -2638,6 +2637,7 @@  scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
 		case SDEV_OFFLINE:
 		case SDEV_TRANSPORT_OFFLINE:
 		case SDEV_CANCEL:
+		case SDEV_BLOCK:
 		case SDEV_CREATED_BLOCK:
 			break;
 		default:
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index a91537a3abbf..1f243ac16010 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -1290,7 +1290,20 @@  void __scsi_remove_device(struct scsi_device *sdev)
 		 * wait until it has finished before changing the device state.
 		 */
 		mutex_lock(&sdev->state_mutex);
+		/*
+		 * If blocked, we go straight to DEL and restart the queue so
+		 * any commands issued during driver shutdown (like sync
+		 * cache) are errored immediately.
+		 */
 		res = scsi_device_set_state(sdev, SDEV_CANCEL);
+		if (res != 0) {
+			res = scsi_device_set_state(sdev, SDEV_DEL);
+			if (res == 0) {
+				scsi_start_queue(sdev);
+				sdev_printk(KERN_DEBUG, sdev,
+				    "Changed state from BLOCKED to DEL\n");
+			}
+		}
 		mutex_unlock(&sdev->state_mutex);
 
 		if (res != 0)