[KJ] Re: [PATCH] 18/34: ieee1394/video1394: replace

[Nishanth Aravamudan <nacc@us.ibm.com>]

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On Tue, Feb 15, 2005 at 05:03:40PM -0500, Jody McIntyre wrote:
> On Tue, Feb 15, 2005 at 10:18:11AM -0800, Nishanth Aravamudan wrote:
> 
> > I am not sure if you have seen some of the discussion (under the
> > subject: "[RFC UPDATE PATCH] add wait_event_*_lock() functions and
> > comments") on LKML regarding these macros. Does Arnd's proposal to fix
> > video1394 seem reasonable? I can throw up a patch, if you'd like to
> > test.
> 
> I just read it now.  Arnd's suggestion looks like it will work.  I
> thought of something similar while reading the thread and his code looks
> correct.  If you have time to make a patch, I'll find some video1394
> users to test it.

If someone could test the following, I think it implements exactly what
Arnd suggested...

Thanks,
Nish

--- 2.6.11-rc4-v/drivers/ieee1394/video1394.c	2005-02-21 09:44:31.000000000 -0800
+++ 2.6.11-rc4/drivers/ieee1394/video1394.c	2005-02-21 09:38:37.000000000 -0800
@@ -699,6 +699,17 @@ static void initialize_dma_it_ctx(struct
 	reg_write(ohci, OHCI1394_IsoXmitIntMaskSet, 1<<d->ctx);
 }
 
+static inline unsigned video1394_buffer_state(struct dma_iso_ctx *d,
+					      unsigned int buffer)
+{
+	unsigned long flags;
+	unsigned int ret;
+	spin_lock_irqsave(&d->lock, flags);
+	ret = d->buffer_status[buffer];
+	spin_unlock_irqrestore(&d->lock, flags);
+	return ret;
+}
+
 static int __video1394_ioctl(struct file *file,
 			     unsigned int cmd, unsigned long arg)
 {
@@ -952,24 +963,12 @@ static int __video1394_ioctl(struct file
 			    return -EINTR;
 			}
 
-#if 1
-			while (d->buffer_status[v.buffer]!=
-			      VIDEO1394_BUFFER_READY) {
-				spin_unlock_irqrestore(&d->lock, flags);
-				interruptible_sleep_on(&d->waitq);
-				spin_lock_irqsave(&d->lock, flags);
-				if (signal_pending(current)) {
-					spin_unlock_irqrestore(&d->lock,flags);
-					return -EINTR;
-				}
-			}
-#else
-			if (wait_event_interruptible(d->waitq,
-						     d->buffer_status[v.buffer]
-						     == VIDEO1394_BUFFER_READY)
-			    == -ERESTARTSYS)
+			spin_unlock_irqrestore(&d->lock, flags);
+			wait_event_interruptible(d->waitq,
+					video1394_buffer_state(d, v.buffer) == VIDEO1394_BUFFER_READY);
+			if (signal_pending(current)) {
 				return -EINTR;
-#endif
+			spin_lock_irqsave(&d->lock, flags);
 			d->buffer_status[v.buffer]=VIDEO1394_BUFFER_FREE;
 			break;
 		default:

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