[PATCH AUTOSEL 5.5 080/121] scsi: core: avoid repetitive logging of device offline messages

Sasha Levin
2020-04-11T23:08:51Z

From: "Ewan D. Milne" <emilne@redhat.com>

[ Upstream commit b0962c53bde9a485c8ebc401fa1dbe821a76bc3e ]

Large queues of I/O to offline devices that are eventually submitted when
devices are unblocked result in a many repeated "rejecting I/O to offline
device" messages. These messages can fill up the dmesg buffer in crash
dumps so no useful prior messages remain. In addition, if a serial console
is used, the flood of messages can cause a hard lockup in the console code.

Introduce a flag indicating the message has already been logged for the
device, and reset the flag when scsi_device_set_state() changes the device
state.

Link: https://lore.kernel.org/r/20200311143930.20674-1-emilne@redhat.com
Reviewed-by: Bart van Assche <bvanassche@acm.org>
Signed-off-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/scsi_lib.c | 8 ++++++--
include/scsi/scsi_device.h | 3 +++
2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 3e7a45d0dacad..22bc288750f28 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1240,8 +1240,11 @@ scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
* commands. The device must be brought online
* before trying any recovery commands.
*/
- sdev_printk(KERN_ERR, sdev,
- "rejecting I/O to offline device\n");
+ if (!sdev->offline_already) {
+ sdev->offline_already = true;
+ sdev_printk(KERN_ERR, sdev,
+ "rejecting I/O to offline device\n");
+ }
return BLK_STS_IOERR;
case SDEV_DEL:
/*
@@ -2338,6 +2341,7 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
break;

}
+ sdev->offline_already = false;
sdev->sdev_state = state;
return 0;

diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 3ed836db53069..3812b93347247 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -203,6 +203,9 @@ struct scsi_device {
unsigned unmap_limit_for_ws:1; /* Use the UNMAP limit for WRITE SAME */
unsigned rpm_autosuspend:1; /* Enable runtime autosuspend at device
* creation time */
+
+ bool offline_already; /* Device offline message logged */
+
atomic_t disk_events_disable_depth; /* disable depth for disk events */

DECLARE_BITMAP(supported_events, SDEV_EVT_MAXBITS); /* supported events */
--
2.20.1