From ee60b2c52ec8ecdcbcd2f85cc117b525f649441f Mon Sep 17 00:00:00 2001 From: Eiichi Tsukata Date: Tue, 11 Feb 2014 14:29:52 +0900 Subject: [PATCH] [SCSI] Add timeout to avoid infinite command retry Currently, scsi error handling in scsi_io_completion() tries to unconditionally requeue scsi command when device keeps some error state. For example, UNIT_ATTENTION causes infinite retry with action == ACTION_RETRY. This is because retryable errors are thought to be temporary and the scsi device will soon recover from those errors. Normally, such retry policy is appropriate because the device will soon recover from temporary error state. But there is no guarantee that device is able to recover from error state immediately. Some hardware error can prevent device from recovering. This patch adds timeout in scsi_io_completion() to avoid infinite command retry in scsi_io_completion(). Once scsi command retry time is longer than this timeout, the command is treated as failure. Signed-off-by: Eiichi Tsukata Signed-off-by: James Bottomley --- drivers/scsi/scsi_lib.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 62ec84b..f97a1a6 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -788,6 +788,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY, ACTION_DELAYED_RETRY} action; char *description = NULL; + unsigned long wait_for = (cmd->allowed + 1) * req->timeout; if (result) { sense_valid = scsi_command_normalize_sense(cmd, &sshdr); @@ -989,6 +990,12 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) action = ACTION_FAIL; } + if (action != ACTION_FAIL && + time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) { + action = ACTION_FAIL; + description = "Command timed out"; + } + switch (action) { case ACTION_FAIL: /* Give up and fail the remainder of the request */ -- 2.7.4