When handling the scsi_request_fn(), when the sd offline happened, sometimes
we will hit the print storm as below:
<3>[ 95.365837] sd 0:0:0:0: rejecting I/O to offline device
<3>[ 95.368633] sd 0:0:0:0: rejecting I/O to offline device
<3>[ 95.369881] sd 0:0:0:0: rejecting I/O to offline device
<3>[ 95.371088] sd 0:0:0:0: rejecting I/O to offline device
...
<3>[ 99.026230] sd 0:0:0:0: rejecting I/O to offline device
<3>[ 99.027196] sd 0:0:0:0: rejecting I/O to offline device
<3>[ 99.028240] sd 0:0:0:0: rejecting I/O to offline device
In our case, the print last almost 4s, and it causes irq is disbled for 4s,
bring system unstable.
Here we create sd_printk_ratelimited to replace it.
Signed-off-by: Liu, Chuansheng <chuansheng....@intel.com>
---
drivers/scsi/scsi_lib.c | 2 +-
include/scsi/scsi_device.h | 10 ++++++++++
2 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index d1549b7..7d8d476 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1570,7 +1570,7 @@ static void scsi_request_fn(struct request_queue *q)
break;
if (unlikely(!scsi_device_online(sdev))) {
- sdev_printk(KERN_ERR, sdev,
+ sdev_printk_ratelimited(KERN_ERR, sdev,
"rejecting I/O to offline device\n");
scsi_kill_request(req, q);
continue;
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index d65fbec..0d7d1be 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -7,6 +7,7 @@
#include <linux/blkdev.h>
#include <scsi/scsi.h>
#include <linux/atomic.h>
+#include <linux/ratelimit.h>
struct device;
struct request_queue;
@@ -235,6 +236,15 @@ struct scsi_dh_data {
#define sdev_printk(prefix, sdev, fmt, a...) \
dev_printk(prefix, &(sdev)->sdev_gendev, fmt, ##a)
+#define sdev_printk_ratelimited(prefix, sdev, fmt, a...) \
+do { \
+ static DEFINE_RATELIMIT_STATE(_rs, \
+ DEFAULT_RATELIMIT_INTERVAL, \
+ DEFAULT_RATELIMIT_BURST); \
+ if (__ratelimit(&_rs)) \
+ dev_printk(prefix, &(sdev)->sdev_gendev, fmt, ##a); \
+} while (0)
+
#define scmd_printk(prefix, scmd, fmt, a...) \
(scmd)->request->rq_disk ? \
sdev_printk(prefix, (scmd)->device, "[%s] " fmt, \
--
1.7.9.5
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