From 6d4dcd4dae25c48e8932326aaedfe560d7f2c7bb Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Thu, 11 Jan 2007 14:15:00 -0800 Subject: [PATCH] [SCSI] libsas: Reset timer on taskless scsi_cmnds in sas_scsi_timed_out Every so often, a scsi_cmnd will time out, and the libsas timeout handler will discover that the scsi_cmnd does not have a sas_task attached to it. This can happen in two cases: (1) the scsi_cmnd actually made it through libsas to the HBA and is now going through scsi_done, or (2) the scsi_cmnd has been held up (host lock, slab alloc, etc) and libsas has not yet attached a sas_task. In both cases, it is safe to ask SCSI for more time to process the command via EH_RESET_TIMER; we cannot blindly return EH_HANDLED because if (2) happens, we could end up calling scsi_done while another CPU is heading towards sas_queuecommand, which causes slab corruption when sas_task_done updates the freed scsi_cmnd. Signed-off-by: Darrick J. Wong Signed-off-by: James Bottomley --- drivers/scsi/libsas/sas_scsi_host.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/scsi/libsas/sas_scsi_host.c b/drivers/scsi/libsas/sas_scsi_host.c index 7774eb3..3f647c6 100644 --- a/drivers/scsi/libsas/sas_scsi_host.c +++ b/drivers/scsi/libsas/sas_scsi_host.c @@ -524,9 +524,13 @@ enum scsi_eh_timer_return sas_scsi_timed_out(struct scsi_cmnd *cmd) unsigned long flags; if (!task) { - SAS_DPRINTK("command 0x%p, task 0x%p, gone: EH_HANDLED\n", - cmd, task); - return EH_HANDLED; + cmd->timeout_per_command /= 2; + SAS_DPRINTK("command 0x%p, task 0x%p, gone: %s\n", + cmd, task, (cmd->timeout_per_command ? + "EH_RESET_TIMER" : "EH_NOT_HANDLED")); + if (!cmd->timeout_per_command) + return EH_NOT_HANDLED; + return EH_RESET_TIMER; } spin_lock_irqsave(&task->task_state_lock, flags); -- 2.7.4