aboutsummaryrefslogtreecommitdiff
path: root/MAINTAINERS
diff options
context:
space:
mode:
authorBodo Stroesser2020-07-26 17:35:08 +0200
committerMartin K. Petersen2020-07-28 22:25:29 -0400
commited212ca878972d6de88ee7f175f84399fc2e3f01 (patch)
tree1f8a54c56a2aa539e66de71cdafd0af62da4eff2 /MAINTAINERS
parent3d3f9d56a57014174ea9b997c95b71b50fdc4cc3 (diff)
scsi: target: tcmu: Fix and simplify timeout handling
During cmd timeout handling in check_timedout_devices(), due to a race, it can happen that tcmu_set_next_deadline() does not start a timer as expected: 1) Either tcmu_check_expired_ring_cmd() checks the inflight_queue or tcmu_check_expired_queue_cmd() checks the qfull_queue while jiffies has the value X 2) At the end of the check the queue contains one remaining command with deadline X (time_after(X, X) is false and thus the command is not handled as being timed out). 3) After tcmu_check_expired_xxxxx_cmd() a timer interrupt happens and jiffies is incremented to X+1. 4) Now tcmu_set_next_deadline() is called, but it skips the command, since time_after(X+1, X) is true. Therefore tcmu_set_next_deadline() finds no new deadline and stops the timer, which it shouldn't. Since commands that time out are removed from inflight_queue or qfull_queue, we don't need the check with time_after() in tcmu_set_next_deadline() but can use the deadline from the first cmd in the queue. Additionally, replace the remaining time_after() calls in tcmu_check_expired_xxxxx_cmd() with time_after_eq(), because it is not useful to set the timeout to deadline but then check for jiffies being greater than deadline. Simplify the end of tcmu_handle_completions() and change the check for no more pending commands from mb->cmd_tail == mb->cmd_head to idr_is_empty(&udev->commands) because the old check doesn't work correctly if paddings or in the future TMRs are in the ring. Finally tcmu_set_next_deadline() was shifted in the source as preparation for later implementation of tmr_notify callback. Link: https://lore.kernel.org/r/20200726153510.13077-7-bstroesser@ts.fujitsu.com Reviewed-by: Mike Christie <michael.christie@oracle.com> Signed-off-by: Bodo Stroesser <bstroesser@ts.fujitsu.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'MAINTAINERS')
0 files changed, 0 insertions, 0 deletions