[Devel] [PATCH RHEL7 COMMIT] scsi: ratelimit messages about rejected I/O

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-1062.7.1.vz7.130.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-1062.7.1.vz7.130.7
------>
commit 734978dda64359d9256a0d9a67ca546044ccc963
Author: Konstantin Khorenko <khorenko at virtuozzo.com>
Date:   Fri Dec 27 18:50:18 2019 +0300

    scsi: ratelimit messages about rejected I/O
    
    Don't flood logs with messages like
    "sd 1:0:0:0: rejecting I/O to offline device".
    
    On one hand this flooding is not useful for investigations,
    on anothre hand it can make serial console to feed up.
    
    https://jira.sw.ru/browse/PSBM-100118
    
    Signed-off-by: Konstantin Khorenko <khorenko at virtuozzo.com>
---
 drivers/scsi/scsi_lib.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index c36e326f46a72..0db8a47be93c0 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1219,6 +1219,8 @@ static int scsi_setup_cmnd(struct scsi_device *sdev, struct request *req)
 static int
 scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
 {
+	static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 10);
+
 	int ret = BLKPREP_OK;
 
 	/*
@@ -1234,8 +1236,9 @@ 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 (__ratelimit(&ratelimit))
+				sdev_printk(KERN_ERR, sdev,
+					"rejecting I/O to offline device\n");
 			ret = BLKPREP_KILL;
 			break;
 		case SDEV_DEL:
@@ -1243,8 +1246,9 @@ scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
 			 * If the device is fully deleted, we refuse to
 			 * process any commands as well.
 			 */
-			sdev_printk(KERN_ERR, sdev,
-				    "rejecting I/O to dead device\n");
+			if (__ratelimit(&ratelimit))
+				sdev_printk(KERN_ERR, sdev,
+					"rejecting I/O to dead device\n");
 			ret = BLKPREP_KILL;
 			break;
 		case SDEV_QUIESCE: