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[SCSI] Unlock accesses to eh_deadline

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32bit accesses are guaranteed to be atomic, so we can remove
the spinlock when checking for eh_deadline. We only need to
make sure to catch any updates which might happened during
the call to time_before(); if so we just recheck with the
correct value.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
Hannes Reinecke 2013-11-11 13:44:55 +01:00 committed by James Bottomley
parent e494f6a728
commit 76ad3e5956
1 changed files with 9 additions and 35 deletions
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44
drivers/scsi/scsi_error.c
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@ -94,8 +94,15 @@ static int scsi_host_eh_past_deadline(struct Scsi_Host *shost)
if (!shost->last_reset || !shost->eh_deadline)
return 0;
if (time_before(jiffies,
shost->last_reset + shost->eh_deadline))
/*
* 32bit accesses are guaranteed to be atomic
* (on all supported architectures), so instead
* of using a spinlock we can as well double check
* if eh_deadline has been unset during the
* time_before call.
*/
if (time_before(jiffies, shost->last_reset + shost->eh_deadline) &&
shost->eh_deadline != 0)
return 0;
return 1;
@ -111,18 +118,14 @@ scmd_eh_abort_handler(struct work_struct *work)
struct scsi_cmnd *scmd =
container_of(work, struct scsi_cmnd, abort_work.work);
struct scsi_device *sdev = scmd->device;
unsigned long flags;
int rtn;
spin_lock_irqsave(sdev->host->host_lock, flags);
if (scsi_host_eh_past_deadline(sdev->host)) {
spin_unlock_irqrestore(sdev->host->host_lock, flags);
SCSI_LOG_ERROR_RECOVERY(3,
scmd_printk(KERN_INFO, scmd,
"scmd %p eh timeout, not aborting\n",
scmd));
} else {
spin_unlock_irqrestore(sdev->host->host_lock, flags);
SCSI_LOG_ERROR_RECOVERY(3,
scmd_printk(KERN_INFO, scmd,
"aborting command %p\n", scmd));
@ -1132,7 +1135,6 @@ int scsi_eh_get_sense(struct list_head *work_q,
struct scsi_cmnd *scmd, *next;
struct Scsi_Host *shost;
int rtn;
unsigned long flags;
list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
@ -1140,16 +1142,13 @@ int scsi_eh_get_sense(struct list_head *work_q,
continue;
shost = scmd->device->host;
spin_lock_irqsave(shost->host_lock, flags);
if (scsi_host_eh_past_deadline(shost)) {
spin_unlock_irqrestore(shost->host_lock, flags);
SCSI_LOG_ERROR_RECOVERY(3,
shost_printk(KERN_INFO, shost,
"skip %s, past eh deadline\n",
__func__));
break;
}
spin_unlock_irqrestore(shost->host_lock, flags);
SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
"%s: requesting sense\n",
current->comm));
@ -1235,26 +1234,21 @@ static int scsi_eh_test_devices(struct list_head *cmd_list,
struct scsi_cmnd *scmd, *next;
struct scsi_device *sdev;
int finish_cmds;
unsigned long flags;
while (!list_empty(cmd_list)) {
scmd = list_entry(cmd_list->next, struct scsi_cmnd, eh_entry);
sdev = scmd->device;
if (!try_stu) {
spin_lock_irqsave(sdev->host->host_lock, flags);
if (scsi_host_eh_past_deadline(sdev->host)) {
/* Push items back onto work_q */
list_splice_init(cmd_list, work_q);
spin_unlock_irqrestore(sdev->host->host_lock,
flags);
SCSI_LOG_ERROR_RECOVERY(3,
shost_printk(KERN_INFO, sdev->host,
"skip %s, past eh deadline",
__func__));
break;
}
spin_unlock_irqrestore(sdev->host->host_lock, flags);
}
finish_cmds = !scsi_device_online(scmd->device) ||
@ -1295,15 +1289,12 @@ static int scsi_eh_abort_cmds(struct list_head *work_q,
LIST_HEAD(check_list);
int rtn;
struct Scsi_Host *shost;
unsigned long flags;
list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
continue;
shost = scmd->device->host;
spin_lock_irqsave(shost->host_lock, flags);
if (scsi_host_eh_past_deadline(shost)) {
spin_unlock_irqrestore(shost->host_lock, flags);
list_splice_init(&check_list, work_q);
SCSI_LOG_ERROR_RECOVERY(3,
shost_printk(KERN_INFO, shost,
@ -1311,7 +1302,6 @@ static int scsi_eh_abort_cmds(struct list_head *work_q,
__func__));
return list_empty(work_q);
}
spin_unlock_irqrestore(shost->host_lock, flags);
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
"0x%p\n", current->comm,
scmd));
@ -1375,19 +1365,15 @@ static int scsi_eh_stu(struct Scsi_Host *shost,
{
struct scsi_cmnd *scmd, *stu_scmd, *next;
struct scsi_device *sdev;
unsigned long flags;
shost_for_each_device(sdev, shost) {
spin_lock_irqsave(shost->host_lock, flags);
if (scsi_host_eh_past_deadline(shost)) {
spin_unlock_irqrestore(shost->host_lock, flags);
SCSI_LOG_ERROR_RECOVERY(3,
shost_printk(KERN_INFO, shost,
"skip %s, past eh deadline\n",
__func__));
break;
}
spin_unlock_irqrestore(shost->host_lock, flags);
stu_scmd = NULL;
list_for_each_entry(scmd, work_q, eh_entry)
if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
@ -1441,20 +1427,16 @@ static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
{
struct scsi_cmnd *scmd, *bdr_scmd, *next;
struct scsi_device *sdev;
unsigned long flags;
int rtn;
shost_for_each_device(sdev, shost) {
spin_lock_irqsave(shost->host_lock, flags);
if (scsi_host_eh_past_deadline(shost)) {
spin_unlock_irqrestore(shost->host_lock, flags);
SCSI_LOG_ERROR_RECOVERY(3,
shost_printk(KERN_INFO, shost,
"skip %s, past eh deadline\n",
__func__));
break;
}
spin_unlock_irqrestore(shost->host_lock, flags);
bdr_scmd = NULL;
list_for_each_entry(scmd, work_q, eh_entry)
if (scmd->device == sdev) {
@ -1515,11 +1497,8 @@ static int scsi_eh_target_reset(struct Scsi_Host *shost,
struct scsi_cmnd *next, *scmd;
int rtn;
unsigned int id;
unsigned long flags;
spin_lock_irqsave(shost->host_lock, flags);
if (scsi_host_eh_past_deadline(shost)) {
spin_unlock_irqrestore(shost->host_lock, flags);
/* push back on work queue for further processing */
list_splice_init(&check_list, work_q);
list_splice_init(&tmp_list, work_q);
@ -1529,7 +1508,6 @@ static int scsi_eh_target_reset(struct Scsi_Host *shost,
__func__));
return list_empty(work_q);
}
spin_unlock_irqrestore(shost->host_lock, flags);
scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry);
id = scmd_id(scmd);
@ -1574,7 +1552,6 @@ static int scsi_eh_bus_reset(struct Scsi_Host *shost,
LIST_HEAD(check_list);
unsigned int channel;
int rtn;
unsigned long flags;
/*
* we really want to loop over the various channels, and do this on
@ -1584,9 +1561,7 @@ static int scsi_eh_bus_reset(struct Scsi_Host *shost,
*/
for (channel = 0; channel <= shost->max_channel; channel++) {
spin_lock_irqsave(shost->host_lock, flags);
if (scsi_host_eh_past_deadline(shost)) {
spin_unlock_irqrestore(shost->host_lock, flags);
list_splice_init(&check_list, work_q);
SCSI_LOG_ERROR_RECOVERY(3,
shost_printk(KERN_INFO, shost,
@ -1594,7 +1569,6 @@ static int scsi_eh_bus_reset(struct Scsi_Host *shost,
__func__));
return list_empty(work_q);
}
spin_unlock_irqrestore(shost->host_lock, flags);
chan_scmd = NULL;
list_for_each_entry(scmd, work_q, eh_entry) {