From patchwork Wed Apr 21 16:10:34 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pawel Osciak X-Patchwork-Id: 93901 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter.kernel.org (8.14.3/8.14.3) with ESMTP id o3LGAp89014301 for ; Wed, 21 Apr 2010 16:11:51 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755891Ab0DUQKk (ORCPT ); Wed, 21 Apr 2010 12:10:40 -0400 Received: from mailout4.w1.samsung.com ([210.118.77.14]:36722 "EHLO mailout4.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755882Ab0DUQKj (ORCPT ); Wed, 21 Apr 2010 12:10:39 -0400 MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: TEXT/PLAIN Received: from eu_spt2 ([210.118.77.14]) by mailout4.w1.samsung.com (Sun Java(tm) System Messaging Server 6.3-8.04 (built Jul 29 2009; 32bit)) with ESMTP id <0L1800I19I9PIF90@mailout4.w1.samsung.com> for linux-media@vger.kernel.org; Wed, 21 Apr 2010 17:10:37 +0100 (BST) Received: from linux.samsung.com ([106.116.38.10]) by spt2.w1.samsung.com (iPlanet Messaging Server 5.2 Patch 2 (built Jul 14 2004)) with ESMTPA id <0L1800HFEI9PFD@spt2.w1.samsung.com> for linux-media@vger.kernel.org; Wed, 21 Apr 2010 17:10:37 +0100 (BST) Received: from localhost.localdomain (unknown [106.116.37.23]) by linux.samsung.com (Postfix) with ESMTP id 3445E27004A; Wed, 21 Apr 2010 18:10:07 +0200 (CEST) Date: Wed, 21 Apr 2010 18:10:34 +0200 From: Pawel Osciak Subject: [PATCH v1 1/2] v4l: videobuf: Add support for out-of-order buffer dequeuing. In-reply-to: <1271866235-14370-1-git-send-email-p.osciak@samsung.com> To: linux-media@vger.kernel.org Cc: p.osciak@samsung.com, m.szyprowski@samsung.com, kyungmin.park@samsung.com Message-id: <1271866235-14370-2-git-send-email-p.osciak@samsung.com> X-Mailer: git-send-email 1.7.0 References: <1271866235-14370-1-git-send-email-p.osciak@samsung.com> Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.3 (demeter.kernel.org [140.211.167.41]); Wed, 21 Apr 2010 16:12:00 +0000 (UTC) diff --git a/drivers/media/video/videobuf-core.c b/drivers/media/video/videobuf-core.c index 77899ca..ea5fd39 100644 --- a/drivers/media/video/videobuf-core.c +++ b/drivers/media/video/videobuf-core.c @@ -95,6 +95,27 @@ int videobuf_waiton(struct videobuf_buffer *vb, int non_blocking, int intr) } EXPORT_SYMBOL_GPL(videobuf_waiton); +int videobuf_has_consumers(struct videobuf_queue *q) +{ + return waitqueue_active(&q->vb_done_wait); +} +EXPORT_SYMBOL_GPL(videobuf_has_consumers); + +void videobuf_buf_finish(struct videobuf_queue *q, struct videobuf_buffer *vb) +{ + unsigned long flags; + + spin_lock_irqsave(&q->vb_done_lock, flags); + list_add_tail(&vb->done_list, &q->vb_done_list); + spin_unlock_irqrestore(&q->vb_done_lock, flags); + + spin_lock_irqsave(q->irqlock, flags); + wake_up(&vb->done); + wake_up_interruptible(&q->vb_done_wait); + spin_unlock_irqrestore(q->irqlock, flags); +} +EXPORT_SYMBOL_GPL(videobuf_buf_finish); + int videobuf_iolock(struct videobuf_queue *q, struct videobuf_buffer *vb, struct v4l2_framebuffer *fbuf) { @@ -153,7 +174,10 @@ void videobuf_queue_core_init(struct videobuf_queue *q, mutex_init(&q->vb_lock); init_waitqueue_head(&q->wait); + init_waitqueue_head(&q->vb_done_wait); INIT_LIST_HEAD(&q->stream); + INIT_LIST_HEAD(&q->vb_done_list); + spin_lock_init(&q->vb_done_lock); } EXPORT_SYMBOL_GPL(videobuf_queue_core_init); @@ -217,6 +241,7 @@ void videobuf_queue_cancel(struct videobuf_queue *q) wake_up_all(&q->bufs[i]->done); } } + wake_up_all(&q->vb_done_wait); spin_unlock_irqrestore(q->irqlock, flags); /* free all buffers + clear queue */ @@ -603,67 +628,81 @@ done: EXPORT_SYMBOL_GPL(videobuf_qbuf); /* Locking: Caller holds q->vb_lock */ -static int stream_next_buffer_check_queue(struct videobuf_queue *q, int noblock) +static int wait_for_buffer(struct videobuf_queue *q, int nonblocking) { - int retval; + int retval = 0; checks: if (!q->streaming) { - dprintk(1, "next_buffer: Not streaming\n"); + dprintk(1, "Not streaming\n"); retval = -EINVAL; - goto done; + goto end; } - if (list_empty(&q->stream)) { - if (noblock) { + /* + * Buffers may be added to vb_done_list without holding the vb_lock, + * but removal is performed only while holding both vb_lock and the + * vb_done_lock spinlock. Thus we can be sure that as long as we hold + * vb_lock, the list will remain not empty if this check succeeds. + */ + if (list_empty(&q->vb_done_list)) { + if (nonblocking) { + dprintk(1, "Nonblocking and no buffers to dequeue\n"); retval = -EAGAIN; - dprintk(2, "next_buffer: no buffers to dequeue\n"); - goto done; - } else { - dprintk(2, "next_buffer: waiting on buffer\n"); - - /* Drop lock to avoid deadlock with qbuf */ - mutex_unlock(&q->vb_lock); - - /* Checking list_empty and streaming is safe without - * locks because we goto checks to validate while - * holding locks before proceeding */ - retval = wait_event_interruptible(q->wait, - !list_empty(&q->stream) || !q->streaming); - mutex_lock(&q->vb_lock); - - if (retval) - goto done; - - goto checks; + goto end; } - } - retval = 0; + /* + * We are streaming and nonblocking, wait for another buffer to + * become ready or for streamoff. vb_lock is released to allow + * streamoff and qbuf in parallel. + */ + mutex_unlock(&q->vb_lock); + /* + * Although the mutex is released here, we will be reevaluating + * both conditions again after reacquiring it. + */ + retval = wait_event_interruptible(q->vb_done_wait, + !list_empty(&q->vb_done_list) || !q->streaming); + mutex_lock(&q->vb_lock); + + if (retval) + goto end; + + goto checks; + } -done: + /* + * At least one buffer is on the vb_done_list and nothing can be removed + * from it without acquiring the vb_lock, which we are holding now. + */ +end: return retval; } /* Locking: Caller holds q->vb_lock */ -static int stream_next_buffer(struct videobuf_queue *q, - struct videobuf_buffer **vb, int nonblocking) +static int get_done_buffer(struct videobuf_queue *q, + struct videobuf_buffer **vb, int nonblocking) { - int retval; - struct videobuf_buffer *buf = NULL; - - retval = stream_next_buffer_check_queue(q, nonblocking); - if (retval) - goto done; - - buf = list_entry(q->stream.next, struct videobuf_buffer, stream); - retval = videobuf_waiton(buf, nonblocking, 1); - if (retval < 0) - goto done; - - *vb = buf; -done: - return retval; + unsigned long flags; + int ret = 0; + + ret = wait_for_buffer(q, nonblocking); + if (ret) + goto end; + + /* + * vb_lock has been held since we last verified that vb_done_list is + * not empty, no need for another list_empty(). + */ + spin_lock_irqsave(&q->vb_done_lock, flags); + *vb = list_first_entry(&q->vb_done_list, struct videobuf_buffer, + done_list); + list_del(&((*vb)->done_list)); + spin_unlock_irqrestore(&q->vb_done_lock, flags); + +end: + return ret; } int videobuf_dqbuf(struct videobuf_queue *q, @@ -676,7 +715,7 @@ int videobuf_dqbuf(struct videobuf_queue *q, mutex_lock(&q->vb_lock); - retval = stream_next_buffer(q, &buf, nonblocking); + retval = get_done_buffer(q, &buf, nonblocking); if (retval < 0) { dprintk(1, "dqbuf: next_buffer error: %i\n", retval); goto done; @@ -1055,12 +1094,25 @@ unsigned int videobuf_poll_stream(struct file *file, { struct videobuf_buffer *buf = NULL; unsigned int rc = 0; + unsigned long flags; mutex_lock(&q->vb_lock); if (q->streaming) { - if (!list_empty(&q->stream)) - buf = list_entry(q->stream.next, - struct videobuf_buffer, stream); + if (list_empty(&q->stream)) { + rc = POLLERR; + goto end; + } + + poll_wait(file, &q->vb_done_wait, wait); + + spin_lock_irqsave(&q->vb_done_lock, flags); + if (!list_empty(&q->vb_done_list)) + buf = list_first_entry(&q->vb_done_list, + struct videobuf_buffer, + done_list); + spin_unlock_irqrestore(&q->vb_done_lock, flags); + if (!buf) + goto end; } else { if (!q->reading) __videobuf_read_start(q); @@ -1074,12 +1126,15 @@ unsigned int videobuf_poll_stream(struct file *file, q->read_off = 0; } buf = q->read_buf; + if (!buf) { + rc = POLLERR; + goto end; + } + + poll_wait(file, &buf->done, wait); } - if (!buf) - rc = POLLERR; if (0 == rc) { - poll_wait(file, &buf->done, wait); if (buf->state == VIDEOBUF_DONE || buf->state == VIDEOBUF_ERROR) { switch (q->type) { @@ -1094,6 +1149,7 @@ unsigned int videobuf_poll_stream(struct file *file, } } } +end: mutex_unlock(&q->vb_lock); return rc; } diff --git a/include/media/videobuf-core.h b/include/media/videobuf-core.h index b1f7bf4..7b1cc94 100644 --- a/include/media/videobuf-core.h +++ b/include/media/videobuf-core.h @@ -82,6 +82,7 @@ struct videobuf_buffer { enum v4l2_field field; enum videobuf_state state; struct list_head stream; /* QBUF/DQBUF list */ + struct list_head done_list; /* touched by irq handler */ struct list_head queue; @@ -160,6 +161,10 @@ struct videobuf_queue { wait_queue_head_t wait; /* wait if queue is empty */ + wait_queue_head_t vb_done_wait; + struct list_head vb_done_list; + spinlock_t vb_done_lock; + enum v4l2_buf_type type; unsigned int inputs; /* for V4L2_BUF_FLAG_INPUT */ unsigned int msize; @@ -206,6 +211,8 @@ void videobuf_queue_core_init(struct videobuf_queue *q, int videobuf_queue_is_busy(struct videobuf_queue *q); void videobuf_queue_cancel(struct videobuf_queue *q); +void videobuf_buf_finish(struct videobuf_queue *q, struct videobuf_buffer *vb); + enum v4l2_field videobuf_next_field(struct videobuf_queue *q); int videobuf_reqbufs(struct videobuf_queue *q, struct v4l2_requestbuffers *req); @@ -235,6 +242,8 @@ unsigned int videobuf_poll_stream(struct file *file, struct videobuf_queue *q, poll_table *wait); +int videobuf_has_consumers(struct videobuf_queue *q); + int videobuf_mmap_setup(struct videobuf_queue *q, unsigned int bcount, unsigned int bsize, enum v4l2_memory memory);