tree 73fae0429ce43ce37845e207cb36da2e8f54d42c
parent 76ad3e5956bf0bc8871ebd19ebda03f2287c966a
author Ren Mingxin <renmx@cn.fujitsu.com> 1384173896 +0100
committer James Bottomley <JBottomley@Parallels.com> 1387467542 -0800

[SCSI] Set the minimum valid value of 'eh_deadline' as 0

The former minimum valid value of 'eh_deadline' is 1s, which means
the earliest occasion to shorten EH is 1 second later since a
command is failed or timed out. But if we want to skip EH steps
ASAP, we have to wait until the first EH step is finished. If the
duration of the first EH step is long, this waiting time is
excruciating. So, it is necessary to accept 0 as the minimum valid
value for 'eh_deadline'.

According to my test, with Hannes' patchset 'New EH command timeout
handler' as well, the minimum IO time is improved from 73s
(eh_deadline = 1) to 43s(eh_deadline = 0) when commands are timed
out by disabling RSCN and target port.

Signed-off-by: Ren Mingxin <renmx@cn.fujitsu.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>