From: Russell King - ARM Linux <linux@arm.linux.org.uk>
Date: Mon, 3 Jan 2011 22:32:05 +0000 (+0000)
Subject: ARM: PL08x: fix missed spin-unlock in pl08x_issue_pending()
X-Git-Tag: firefly_0821_release~7613^2~2671^2~11^2~42
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=9c0bb43bbd02fba0b235f8993d1f175734fa8735;p=firefly-linux-kernel-4.4.55.git

ARM: PL08x: fix missed spin-unlock in pl08x_issue_pending()

pl08x_issue_pending() returns with the spinlock locked and interrupts
disabled if the channel is waiting for a physical DMA to become free.
This is wrong - especially as pl08x_issue_pending() is an API function
as it leads to deadlocks.  Fix it to always return with the spinlock
unlocked.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---

diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index b3b3180ce561..9a8d44504c6a 100644
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -1294,15 +1294,11 @@ static void pl08x_issue_pending(struct dma_chan *chan)
 	unsigned long flags;
 
 	spin_lock_irqsave(&plchan->lock, flags);
-	/* Something is already active */
-	if (plchan->at) {
-			spin_unlock_irqrestore(&plchan->lock, flags);
-			return;
-	}
-
-	/* Didn't get a physical channel so waiting for it ... */
-	if (plchan->state == PL08X_CHAN_WAITING)
+	/* Something is already active, or we're waiting for a channel... */
+	if (plchan->at || plchan->state == PL08X_CHAN_WAITING) {
+		spin_unlock_irqrestore(&plchan->lock, flags);
 		return;
+	}
 
 	/* Take the first element in the queue and execute it */
 	if (!list_empty(&plchan->desc_list)) {