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Commit 76ad3e59 authored by Hannes Reinecke's avatar Hannes Reinecke Committed by James Bottomley
Browse files

[SCSI] Unlock accesses to eh_deadline 



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: default avatarHannes Reinecke <hare@suse.de>
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent e494f6a7

drivers/scsi/scsi_error.c

+9 −35
Original line number Diff line number Diff line
@@ -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) {