vmw_pvscsi: return SUCCESS for successful command aborts

From: "David Jeffery" <[email protected]>
To: [email protected]
Sent: Friday, October 28, 2016 12:27:26 PM
Subject: [PATCH] vmw_pvscsi: return SUCCESS for successful command aborts

The vmw_pvscsi driver reports most successful aborts as FAILED to the scsi error handler. This is do to a misunderstanding of how completion_done() works
and its interaction with a successful wait using wait_for_completion_timeout().
The vmw_pvscsi driver is expecting completion_done() to always return true if complete() has been called on the completion structure. But completion_done()
returns true after complete() has been called only if no function like wait_for_completion_timeout() has seen the completion and cleared it as part of
successfully waiting for the completion.

Instead of using completion_done(), vmw_pvscsi should just use the return value from wait_for_completion_timeout() to know if the wait timed out or not.

Signed-off-by David Jeffery <[email protected]>

---
 vmw_pvscsi.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

drivers/scsi/vmw_pvscsi.c +3 -3

@@ -793,6 +793,7 @@ static int pvscsi_abort(struct scsi_cmnd
 	unsigned long flags;
 	int result = SUCCESS;
 	DECLARE_COMPLETION_ONSTACK(abort_cmp);
+	int done;
 
 	scmd_printk(KERN_DEBUG, cmd, "task abort on host %u, %p\n",
 		    adapter->host->host_no, cmd);

@@ -824,10 +825,10 @@ static int pvscsi_abort(struct scsi_cmnd
 	pvscsi_abort_cmd(adapter, ctx);
 	spin_unlock_irqrestore(&adapter->hw_lock, flags);
 	/* Wait for 2 secs for the completion. */
-	wait_for_completion_timeout(&abort_cmp, msecs_to_jiffies(2000));
+	done = wait_for_completion_timeout(&abort_cmp, msecs_to_jiffies(2000));
 	spin_lock_irqsave(&adapter->hw_lock, flags);
 
-	if (!completion_done(&abort_cmp)) {
+	if (!done) {
 		/*
 		 * Failed to abort the command, unmark the fact that it
 		 * was requested to be aborted.
--

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The vmw_pvscsi driver reports most successful aborts as FAILED to the scsi error handler. This is do to a misunderstanding of how completion_done() works and its interaction with a successful wait using wait_for_completion_timeout(). The vmw_pvscsi driver is expecting completion_done() to always return true if complete() has been called on the completion structure. But completion_done() returns true after complete() has been called only if no function like wait_for_completion_timeout() has seen the completion and cleared it as part of successfully waiting for the completion.

Instead of using completion_done(), vmw_pvscsi should just use the return value from wait_for_completion_timeout() to know if the wait timed out or not.

Signed-off-by David Jeffery <[email protected]>

---
 vmw_pvscsi.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

drivers/scsi/vmw_pvscsi.c +3 -3

@@ -793,6 +793,7 @@ static int pvscsi_abort(struct scsi_cmnd
 	unsigned long flags;
 	int result = SUCCESS;
 	DECLARE_COMPLETION_ONSTACK(abort_cmp);
+	int done;
 
 	scmd_printk(KERN_DEBUG, cmd, "task abort on host %u, %p\n",
 		    adapter->host->host_no, cmd);

@@ -824,10 +825,10 @@ static int pvscsi_abort(struct scsi_cmnd
 	pvscsi_abort_cmd(adapter, ctx);
 	spin_unlock_irqrestore(&adapter->hw_lock, flags);
 	/* Wait for 2 secs for the completion. */
-	wait_for_completion_timeout(&abort_cmp, msecs_to_jiffies(2000));
+	done = wait_for_completion_timeout(&abort_cmp, msecs_to_jiffies(2000));
 	spin_lock_irqsave(&adapter->hw_lock, flags);
 
-	if (!completion_done(&abort_cmp)) {
+	if (!done) {
 		/*
 		 * Failed to abort the command, unmark the fact that it
 		 * was requested to be aborted.
--

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