public inbox for linux-media@vger.kernel.org
 help / color / mirror / Atom feed
From: Brandon Philips <brandon@ifup.org>
To: mchehab@infradead.org
Cc: v4l-dvb-maintainer@linuxtv.org, video4linux-list@redhat.com
Subject: [PATCH 2 of 9] videobuf: Require spinlocks for all videobuf users
Date: Fri, 28 Mar 2008 03:18:33 -0700	[thread overview]
Message-ID: <d9780aaf14ad2fca7eea.1206699513@localhost> (raw)
In-Reply-To: <patchbomb.1206699511@localhost>

# HG changeset patch
# User Brandon Philips <brandon@ifup.org>
# Date 1206699277 25200
# Node ID d9780aaf14ad2fca7eeaa79f3a8476e5f551ed25
# Parent  7876c2bc2446dc3e3630e7a30a76f50874116cf1
videobuf: Require spinlocks for all videobuf users

A spinlock is necessary for queue_cancel to work with every driver in the tree.
Otherwise a race exists between IRQ handlers removing buffers from the queue
and queue_cancel invalidating the queue.

Signed-off-by: Brandon Philips <bphilips@suse.de>

---
 linux/drivers/media/video/videobuf-core.c |   46 +++++++++++-------------------
 1 file changed, 18 insertions(+), 28 deletions(-)

diff --git a/linux/drivers/media/video/videobuf-core.c b/linux/drivers/media/video/videobuf-core.c
--- a/linux/drivers/media/video/videobuf-core.c
+++ b/linux/drivers/media/video/videobuf-core.c
@@ -145,6 +145,9 @@ void videobuf_queue_core_init(struct vid
 	BUG_ON(!q->ops->buf_queue);
 	BUG_ON(!q->ops->buf_release);
 
+	/* Lock is mandatory for queue_cancel to work */
+	BUG_ON(!irqlock);
+
 	/* Having implementations for abstract methods are mandatory */
 	BUG_ON(!q->int_ops);
 
@@ -197,8 +200,7 @@ void videobuf_queue_cancel(struct videob
 	int i;
 
 	/* remove queued buffers from list */
-	if (q->irqlock)
-		spin_lock_irqsave(q->irqlock, flags);
+	spin_lock_irqsave(q->irqlock, flags);
 	for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 		if (NULL == q->bufs[i])
 			continue;
@@ -207,8 +209,7 @@ void videobuf_queue_cancel(struct videob
 			q->bufs[i]->state = VIDEOBUF_ERROR;
 		}
 	}
-	if (q->irqlock)
-		spin_unlock_irqrestore(q->irqlock, flags);
+	spin_unlock_irqrestore(q->irqlock, flags);
 
 	/* free all buffers + clear queue */
 	for (i = 0; i < VIDEO_MAX_FRAME; i++) {
@@ -564,11 +565,9 @@ int videobuf_qbuf(struct videobuf_queue 
 
 	list_add_tail(&buf->stream, &q->stream);
 	if (q->streaming) {
-		if (q->irqlock)
-			spin_lock_irqsave(q->irqlock, flags);
+		spin_lock_irqsave(q->irqlock, flags);
 		q->ops->buf_queue(q, buf);
-		if (q->irqlock)
-			spin_unlock_irqrestore(q->irqlock, flags);
+		spin_unlock_irqrestore(q->irqlock, flags);
 	}
 	dprintk(1, "qbuf: succeded\n");
 	retval = 0;
@@ -653,13 +652,11 @@ int videobuf_streamon(struct videobuf_qu
 	if (q->streaming)
 		goto done;
 	q->streaming = 1;
-	if (q->irqlock)
-		spin_lock_irqsave(q->irqlock, flags);
+	spin_lock_irqsave(q->irqlock, flags);
 	list_for_each_entry(buf, &q->stream, stream)
 		if (buf->state == VIDEOBUF_PREPARED)
 			q->ops->buf_queue(q, buf);
-	if (q->irqlock)
-		spin_unlock_irqrestore(q->irqlock, flags);
+	spin_unlock_irqrestore(q->irqlock, flags);
 
  done:
 	mutex_unlock(&q->vb_lock);
@@ -715,11 +712,9 @@ static ssize_t videobuf_read_zerocopy(st
 		goto done;
 
 	/* start capture & wait */
-	if (q->irqlock)
-		spin_lock_irqsave(q->irqlock, flags);
+	spin_lock_irqsave(q->irqlock, flags);
 	q->ops->buf_queue(q, q->read_buf);
-	if (q->irqlock)
-		spin_unlock_irqrestore(q->irqlock, flags);
+	spin_unlock_irqrestore(q->irqlock, flags);
 	retval = videobuf_waiton(q->read_buf, 0, 0);
 	if (0 == retval) {
 		CALL(q, sync, q, q->read_buf);
@@ -780,12 +775,11 @@ ssize_t videobuf_read_one(struct videobu
 			q->read_buf = NULL;
 			goto done;
 		}
-		if (q->irqlock)
-			spin_lock_irqsave(q->irqlock, flags);
 
+		spin_lock_irqsave(q->irqlock, flags);
 		q->ops->buf_queue(q, q->read_buf);
-		if (q->irqlock)
-			spin_unlock_irqrestore(q->irqlock, flags);
+		spin_unlock_irqrestore(q->irqlock, flags);
+
 		q->read_off = 0;
 	}
 
@@ -851,12 +845,10 @@ static int __videobuf_read_start(struct 
 			return err;
 		list_add_tail(&q->bufs[i]->stream, &q->stream);
 	}
-	if (q->irqlock)
-		spin_lock_irqsave(q->irqlock, flags);
+	spin_lock_irqsave(q->irqlock, flags);
 	for (i = 0; i < count; i++)
 		q->ops->buf_queue(q, q->bufs[i]);
-	if (q->irqlock)
-		spin_unlock_irqrestore(q->irqlock, flags);
+	spin_unlock_irqrestore(q->irqlock, flags);
 	q->reading = 1;
 	return 0;
 }
@@ -970,11 +962,9 @@ ssize_t videobuf_read_stream(struct vide
 		if (q->read_off == q->read_buf->size) {
 			list_add_tail(&q->read_buf->stream,
 				      &q->stream);
-			if (q->irqlock)
-				spin_lock_irqsave(q->irqlock, flags);
+			spin_lock_irqsave(q->irqlock, flags);
 			q->ops->buf_queue(q, q->read_buf);
-			if (q->irqlock)
-				spin_unlock_irqrestore(q->irqlock, flags);
+			spin_unlock_irqrestore(q->irqlock, flags);
 			q->read_buf = NULL;
 		}
 		if (retval < 0)

--
video4linux-list mailing list
Unsubscribe mailto:video4linux-list-request@redhat.com?subject=unsubscribe
https://www.redhat.com/mailman/listinfo/video4linux-list

  parent reply	other threads:[~2008-03-28 10:34 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-03-28 10:18 [PATCH 0 of 9] videobuf fixes Brandon Philips
2008-03-28 10:18 ` [PATCH 1 of 9] soc_camera: Introduce a spinlock for use with videobuf Brandon Philips
2008-03-28 20:53   ` Guennadi Liakhovetski
2008-03-29  3:59     ` Brandon Philips
2008-04-04 13:46       ` [PATCH] soc-camera: use a spinlock for videobuffer queue Guennadi Liakhovetski
2008-04-04 20:17         ` Brandon Philips
2008-03-28 10:18 ` Brandon Philips [this message]
2008-03-28 10:18 ` [PATCH 3 of 9] videobuf: Wakeup queues after changing the state to ERROR Brandon Philips
2008-03-28 10:18 ` [PATCH 4 of 9] videobuf: Simplify videobuf_waiton logic and possibly avoid missed wakeup Brandon Philips
2008-03-28 10:18 ` [PATCH 5 of 9] videobuf-vmalloc.c: Remove buf_release from videobuf_vm_close Brandon Philips
2008-03-28 10:18 ` [PATCH 6 of 9] videobuf-vmalloc.c: Fix hack of postponing mmap on remap failure Brandon Philips
     [not found]   ` <20080405131236.7c083554@gaivota>
     [not found]     ` <20080406080011.GA3596@plankton.ifup.org>
     [not found]       ` <20080407183226.703217fc@gaivota>
     [not found]         ` <20080408152238.GA8438@plankton.public.utexas.edu>
2008-04-08 18:40           ` Mauro Carvalho Chehab
     [not found]             ` <c8b4dbe10804081306xb1e8f91q64d1e6d18d3d2531@mail.gmail.com>
2008-04-08 20:50               ` Mauro Carvalho Chehab
     [not found]                 ` <c8b4dbe10804090626l6b2b10d9p1c22e02dfe2850fe@mail.gmail.com>
2008-04-09 20:42                   ` Mauro Carvalho Chehab
     [not found]             ` <20080408204514.GA6844@plankton.public.utexas.edu>
2008-04-08 21:37               ` Mauro Carvalho Chehab
     [not found]                 ` <20080415021558.GA22068@plankton.ifup.org>
2008-04-15 14:10                   ` Mauro Carvalho Chehab
2008-03-28 10:18 ` [PATCH 7 of 9] vivi: Simplify the vivi driver and avoid deadlocks Brandon Philips
2008-03-28 18:34   ` Mauro Carvalho Chehab
2008-03-29  5:35     ` Brandon Philips
2008-03-31 19:35       ` Mauro Carvalho Chehab
2008-03-28 10:18 ` [PATCH 8 of 9] videobuf: Avoid deadlock with QBUF and bring up to spec for empty queue Brandon Philips
2008-03-28 10:18 ` [PATCH 9 of 9] videobuf-dma-sg.c: Avoid NULL dereference and add comment about backwards compatibility Brandon Philips
2008-03-28 19:09 ` [PATCH 0 of 9] videobuf fixes Mauro Carvalho Chehab
2008-03-29  5:25   ` Brandon Philips
2008-03-29 22:49     ` Vanessa Ezekowitz
2008-03-31 18:35     ` Mauro Carvalho Chehab
2008-03-31 19:26       ` Brandon Philips
2008-03-31 21:31         ` Mauro Carvalho Chehab
2008-04-01  3:11           ` Brandon Philips
2008-04-01 20:49             ` Mauro Carvalho Chehab
2008-04-02 18:54               ` Brandon Philips
2008-04-02 20:06                 ` Mauro Carvalho Chehab
2008-04-02 18:56               ` Brandon Philips

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=d9780aaf14ad2fca7eea.1206699513@localhost \
    --to=brandon@ifup.org \
    --cc=mchehab@infradead.org \
    --cc=v4l-dvb-maintainer@linuxtv.org \
    --cc=video4linux-list@redhat.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox