scsi: core: avoid repetitive logging of device offline messages (b0962c53) · Commits · 戴 / test

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>

drivers/scsi/scsi_lib.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -1215,8 +1215,11 @@ scsi_prep_state_check(struct scsi_device sdev, struct request req)
		* commands. The device must be brought online
		* before trying any recovery commands.
		*/
		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:
		/*
		@@ -2326,6 +2329,7 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
		break;

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

include/scsi/scsi_device.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -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 */

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