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[SCSI] libsas: fix lifetime of SAS_HA_FROZEN 

Until all sas_tasks are known to no longer be in-flight this flag gates late
completions from colliding with error handling.  However, it must be cleared
prior to the submission of scsi_send_eh_cmnd() requests, otherwise those
commands will never be completed correctly.

This was spotted by slub debug:
 =============================================================================
 BUG sas_task: Objects remaining on kmem_cache_close()
 -----------------------------------------------------------------------------

 INFO: Slab 0xffffea001f0eba00 objects=34 used=1 fp=0xffff8807c3aecb00 flags=0x8000000000004080
 Pid: 22919, comm: modprobe Not tainted 3.2.0-isci+ #2
 Call Trace:
  [<ffffffff810fcdcd>] slab_err+0xb0/0xd2
  [<ffffffff810e1c50>] ? free_percpu+0x31/0x117
  [<ffffffff81100122>] ? kzalloc+0x14/0x16
  [<ffffffff81100122>] ? kzalloc+0x14/0x16
  [<ffffffff81100486>] kmem_cache_destroy+0x11d/0x270
  [<ffffffffa0112bdc>] sas_class_exit+0x10/0x12 [libsas]
  [<ffffffff81078fba>] sys_delete_module+0x1c4/0x23c
  [<ffffffff814797ba>] ? sysret_check+0x2e/0x69
  [<ffffffff8126479e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
  [<ffffffff81479782>] system_call_fastpath+0x16/0x1b
 INFO: Object 0xffff8807c3aed280 @offset=21120
 INFO: Allocated in sas_alloc_task+0x22/0x90 [libsas] age=4615311 cpu=2 pid=12966
  __slab_alloc.clone.3+0x1d1/0x234
  kmem_cache_alloc+0x52/0x10d
  sas_alloc_task+0x22/0x90 [libsas]
  sas_queuecommand+0x20e/0x230 [libsas]
  scsi_send_eh_cmnd+0xd1/0x30c
  scsi_eh_try_stu+0x4f/0x6b
  scsi_eh_ready_devs+0xba/0x6ef
  sas_scsi_recover_host+0xa35/0xab1 [libsas]
  scsi_error_handler+0x14b/0x5fa
  kthread+0x9d/0xa5
  kernel_thread_helper+0x4/0x10

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
Dan Williams 2012-01-20 15:23:07 -08:00 committed by James Bottomley
parent 9508a66f89
commit 840234745e
1 changed files with 7 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/scsi/libsas/sas_scsi_host.c
View File

@ -521,8 +521,7 @@ static int try_to_reset_cmd_device(struct scsi_cmnd *cmd)
return FAILED;
}
static int sas_eh_handle_sas_errors(struct Scsi_Host *shost,
struct list_head *work_q)
static void sas_eh_handle_sas_errors(struct Scsi_Host *shost, struct list_head *work_q)
{
struct scsi_cmnd *cmd, *n;
enum task_disposition res = TASK_IS_DONE;
@ -658,7 +657,7 @@ static int sas_eh_handle_sas_errors(struct Scsi_Host *shost,
out:
list_splice_tail(&done, work_q);
list_splice_tail_init(&ha->eh_ata_q, work_q);
return list_empty(work_q);
return;
clear_q:
SAS_DPRINTK("--- Exit %s -- clear_q\n", __func__);
@ -682,10 +681,13 @@ void sas_scsi_recover_host(struct Scsi_Host *shost)
__func__, shost->host_busy, shost->host_failed);
/*
* Deal with commands that still have SAS tasks (i.e. they didn't
* complete via the normal sas_task completion mechanism)
* complete via the normal sas_task completion mechanism),
* SAS_HA_FROZEN gives eh dominion over all sas_task completion.
*/
set_bit(SAS_HA_FROZEN, &ha->state);
if (sas_eh_handle_sas_errors(shost, &eh_work_q))
sas_eh_handle_sas_errors(shost, &eh_work_q);
clear_bit(SAS_HA_FROZEN, &ha->state);
if (list_empty(&eh_work_q))
goto out;
/*
@ -699,7 +701,6 @@ void sas_scsi_recover_host(struct Scsi_Host *shost)
scsi_eh_ready_devs(shost, &eh_work_q, &ha->eh_done_q);
out:
clear_bit(SAS_HA_FROZEN, &ha->state);
if (ha->lldd_max_execute_num > 1)
wake_up_process(ha->core.queue_thread);