ipr: wait for aborted command responses

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.

Cc: <stable@vger.kernel.org>
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>

diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index df4e27cd996a3c68cf095e40d7a6ccf7ebf6a065..9219953ee949a9dfaf1ff0f044e41a3e5c13adc7 100644 (file)
--- 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);
 }
 
@@ -4811,6 +4814,84 @@ 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 = ∁
+                                       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;
@@ -5030,11 +5111,17 @@ 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;
 }
 
@@ -5234,13 +5321,18 @@ 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 b4f3eec51bc9b19783f931116f63aa70bc2d235a..ec03b42fa2b9fe0f388bc266fd75e8190460f682 100644 (file)
--- a/drivers/scsi/ipr.h
+++ b/drivers/scsi/ipr.h
@@ -1606,6 +1606,7 @@ struct ipr_cmnd {
                struct scsi_device *sdev;
        } u;
 
+       struct completion *eh_comp;
        struct ipr_hrr_queue *hrrq;
        struct ipr_ioa_cfg *ioa_cfg;
 };