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[3.13.y-ckt,stable] Patch "ipr: wait for aborted command responses" has been added to staging queue

Message ID 1424305754-16836-1-git-send-email-kamal@canonical.com
State New
Headers show

Commit Message

Kamal Mostafa Feb. 19, 2015, 12:29 a.m. UTC
This is a note to let you know that I have just added a patch titled

    ipr: wait for aborted command responses

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt16.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

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From efac4131b79a0e2e10562fa2f7690ea11ffa04b9 Mon Sep 17 00:00:00 2001
From: Brian King <brking@linux.vnet.ibm.com>
Date: Thu, 30 Oct 2014 17:27:10 -0500
Subject: ipr: wait for aborted command responses

commit 6cdb08172bc89f0a39e1643c5e7eab362692fd1b upstream.

Fixes a race condition in abort handling that was injected
when multiple interrupt support was added. When only a single
interrupt is present, the adapter guarantees it will send
responses for aborted commands prior to the response for the
abort command itself. With multiple interrupts, these responses
generally come back on different interrupts, so we need to
ensure the abort thread waits until the aborted command is
complete so we don't perform a double completion. This race
condition was being hit frequently in environments which
were triggering command timeouts, which was resulting in
a double completion causing a kernel oops.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Reviewed-by: Wendy Xiong <wenxiong@linux.vnet.ibm.com>
Tested-by: Wendy Xiong <wenxiong@linux.vnet.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 drivers/scsi/ipr.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 drivers/scsi/ipr.h |  1 +
 2 files changed, 93 insertions(+)

--
1.9.1
diff mbox

Patch

diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index 573f412..8c2f6ab 100644
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -683,6 +683,7 @@  static void ipr_init_ipr_cmnd(struct ipr_cmnd *ipr_cmd,
 	ipr_reinit_ipr_cmnd(ipr_cmd);
 	ipr_cmd->u.scratch = 0;
 	ipr_cmd->sibling = NULL;
+	ipr_cmd->eh_comp = NULL;
 	ipr_cmd->fast_done = fast_done;
 	init_timer(&ipr_cmd->timer);
 }
@@ -848,6 +849,8 @@  static void ipr_scsi_eh_done(struct ipr_cmnd *ipr_cmd)

 	scsi_dma_unmap(ipr_cmd->scsi_cmd);
 	scsi_cmd->scsi_done(scsi_cmd);
+	if (ipr_cmd->eh_comp)
+		complete(ipr_cmd->eh_comp);
 	list_add_tail(&ipr_cmd->queue, &ipr_cmd->hrrq->hrrq_free_q);
 }

@@ -4805,6 +4808,84 @@  static int ipr_slave_alloc(struct scsi_device *sdev)
 	return rc;
 }

+/**
+ * ipr_match_lun - Match function for specified LUN
+ * @ipr_cmd:	ipr command struct
+ * @device:		device to match (sdev)
+ *
+ * Returns:
+ *	1 if command matches sdev / 0 if command does not match sdev
+ **/
+static int ipr_match_lun(struct ipr_cmnd *ipr_cmd, void *device)
+{
+	if (ipr_cmd->scsi_cmd && ipr_cmd->scsi_cmd->device == device)
+		return 1;
+	return 0;
+}
+
+/**
+ * ipr_wait_for_ops - Wait for matching commands to complete
+ * @ipr_cmd:	ipr command struct
+ * @device:		device to match (sdev)
+ * @match:		match function to use
+ *
+ * Returns:
+ *	SUCCESS / FAILED
+ **/
+static int ipr_wait_for_ops(struct ipr_ioa_cfg *ioa_cfg, void *device,
+			    int (*match)(struct ipr_cmnd *, void *))
+{
+	struct ipr_cmnd *ipr_cmd;
+	int wait;
+	unsigned long flags;
+	struct ipr_hrr_queue *hrrq;
+	signed long timeout = IPR_ABORT_TASK_TIMEOUT;
+	DECLARE_COMPLETION_ONSTACK(comp);
+
+	ENTER;
+	do {
+		wait = 0;
+
+		for_each_hrrq(hrrq, ioa_cfg) {
+			spin_lock_irqsave(hrrq->lock, flags);
+			list_for_each_entry(ipr_cmd, &hrrq->hrrq_pending_q, queue) {
+				if (match(ipr_cmd, device)) {
+					ipr_cmd->eh_comp = &comp;
+					wait++;
+				}
+			}
+			spin_unlock_irqrestore(hrrq->lock, flags);
+		}
+
+		if (wait) {
+			timeout = wait_for_completion_timeout(&comp, timeout);
+
+			if (!timeout) {
+				wait = 0;
+
+				for_each_hrrq(hrrq, ioa_cfg) {
+					spin_lock_irqsave(hrrq->lock, flags);
+					list_for_each_entry(ipr_cmd, &hrrq->hrrq_pending_q, queue) {
+						if (match(ipr_cmd, device)) {
+							ipr_cmd->eh_comp = NULL;
+							wait++;
+						}
+					}
+					spin_unlock_irqrestore(hrrq->lock, flags);
+				}
+
+				if (wait)
+					dev_err(&ioa_cfg->pdev->dev, "Timed out waiting for aborted commands\n");
+				LEAVE;
+				return wait ? FAILED : SUCCESS;
+			}
+		}
+	} while (wait);
+
+	LEAVE;
+	return SUCCESS;
+}
+
 static int ipr_eh_host_reset(struct scsi_cmnd *cmd)
 {
 	struct ipr_ioa_cfg *ioa_cfg;
@@ -5023,11 +5104,17 @@  static int __ipr_eh_dev_reset(struct scsi_cmnd *scsi_cmd)
 static int ipr_eh_dev_reset(struct scsi_cmnd *cmd)
 {
 	int rc;
+	struct ipr_ioa_cfg *ioa_cfg;
+
+	ioa_cfg = (struct ipr_ioa_cfg *) cmd->device->host->hostdata;

 	spin_lock_irq(cmd->device->host->host_lock);
 	rc = __ipr_eh_dev_reset(cmd);
 	spin_unlock_irq(cmd->device->host->host_lock);

+	if (rc == SUCCESS)
+		rc = ipr_wait_for_ops(ioa_cfg, cmd->device, ipr_match_lun);
+
 	return rc;
 }

@@ -5205,13 +5292,18 @@  static int ipr_eh_abort(struct scsi_cmnd *scsi_cmd)
 {
 	unsigned long flags;
 	int rc;
+	struct ipr_ioa_cfg *ioa_cfg;

 	ENTER;

+	ioa_cfg = (struct ipr_ioa_cfg *) scsi_cmd->device->host->hostdata;
+
 	spin_lock_irqsave(scsi_cmd->device->host->host_lock, flags);
 	rc = ipr_cancel_op(scsi_cmd);
 	spin_unlock_irqrestore(scsi_cmd->device->host->host_lock, flags);

+	if (rc == SUCCESS)
+		rc = ipr_wait_for_ops(ioa_cfg, scsi_cmd->device, ipr_match_lun);
 	LEAVE;
 	return rc;
 }
diff --git a/drivers/scsi/ipr.h b/drivers/scsi/ipr.h
index cad1483..aac8293 100644
--- a/drivers/scsi/ipr.h
+++ b/drivers/scsi/ipr.h
@@ -1585,6 +1585,7 @@  struct ipr_cmnd {
 		struct scsi_device *sdev;
 	} u;

+	struct completion *eh_comp;
 	struct ipr_hrr_queue *hrrq;
 	struct ipr_ioa_cfg *ioa_cfg;
 };