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Subject[patch 42/62] V4L: uvcvideo: Dont free URB buffers on suspend

2.6.26 -stable review patch. If anyone has any objections, please let
us know.

------------------
From: Laurent Pinchart <laurent.pinchart@skynet.be>
(cherry picked from commit e01117c81676dc9897f567e32cdc13a26e85280b)

V4L: uvcvideo: Don't free URB buffers on suspend.

All submitted URBs must be killed at suspend time, but URB buffers don't
have to be freed. Avoiding a free on suspend/reallocate on resume lowers
the pressure on system memory.

Signed-off-by: Laurent Pinchart <laurent.pinchart@skynet.be>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/media/video/uvc/uvc_video.c | 96 ++++++++++++++++++++++++------------
drivers/media/video/uvc/uvcvideo.h | 2
2 files changed, 66 insertions(+), 32 deletions(-)
--- a/drivers/media/video/uvc/uvc_video.c
+++ b/drivers/media/video/uvc/uvc_video.c
@@ -554,9 +554,56 @@ static void uvc_video_complete(struct ur
}

/*
+ * Free transfer buffers.
+ */
+static void uvc_free_urb_buffers(struct uvc_video_device *video)
+{
+ unsigned int i;
+
+ for (i = 0; i < UVC_URBS; ++i) {
+ if (video->urb_buffer[i]) {
+ usb_buffer_free(video->dev->udev, video->urb_size,
+ video->urb_buffer[i], video->urb_dma[i]);
+ video->urb_buffer[i] = NULL;
+ }
+ }
+
+ video->urb_size = 0;
+}
+
+/*
+ * Allocate transfer buffers. This function can be called with buffers
+ * already allocated when resuming from suspend, in which case it will
+ * return without touching the buffers.
+ *
+ * Return 0 on success or -ENOMEM when out of memory.
+ */
+static int uvc_alloc_urb_buffers(struct uvc_video_device *video,
+ unsigned int size)
+{
+ unsigned int i;
+
+ /* Buffers are already allocated, bail out. */
+ if (video->urb_size)
+ return 0;
+
+ for (i = 0; i < UVC_URBS; ++i) {
+ video->urb_buffer[i] = usb_buffer_alloc(video->dev->udev,
+ size, GFP_KERNEL, &video->urb_dma[i]);
+ if (video->urb_buffer[i] == NULL) {
+ uvc_free_urb_buffers(video);
+ return -ENOMEM;
+ }
+ }
+
+ video->urb_size = size;
+ return 0;
+}
+
+/*
* Uninitialize isochronous/bulk URBs and free transfer buffers.
*/
-static void uvc_uninit_video(struct uvc_video_device *video)
+static void uvc_uninit_video(struct uvc_video_device *video, int free_buffers)
{
struct urb *urb;
unsigned int i;
@@ -566,19 +613,12 @@ static void uvc_uninit_video(struct uvc_
continue;

usb_kill_urb(urb);
- /* urb->transfer_buffer_length is not touched by USB core, so
- * we can use it here as the buffer length.
- */
- if (video->urb_buffer[i]) {
- usb_buffer_free(video->dev->udev,
- urb->transfer_buffer_length,
- video->urb_buffer[i], urb->transfer_dma);
- video->urb_buffer[i] = NULL;
- }
-
usb_free_urb(urb);
video->urb[i] = NULL;
}
+
+ if (free_buffers)
+ uvc_free_urb_buffers(video);
}

/*
@@ -610,18 +650,13 @@ static int uvc_init_video_isoc(struct uv

size = npackets * psize;

+ if (uvc_alloc_urb_buffers(video, size) < 0)
+ return -ENOMEM;
+
for (i = 0; i < UVC_URBS; ++i) {
urb = usb_alloc_urb(npackets, gfp_flags);
if (urb == NULL) {
- uvc_uninit_video(video);
- return -ENOMEM;
- }
-
- video->urb_buffer[i] = usb_buffer_alloc(video->dev->udev,
- size, gfp_flags, &urb->transfer_dma);
- if (video->urb_buffer[i] == NULL) {
- usb_free_urb(urb);
- uvc_uninit_video(video);
+ uvc_uninit_video(video, 1);
return -ENOMEM;
}

@@ -632,6 +667,7 @@ static int uvc_init_video_isoc(struct uv
urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
urb->interval = ep->desc.bInterval;
urb->transfer_buffer = video->urb_buffer[i];
+ urb->transfer_dma = video->urb_dma[i];
urb->complete = uvc_video_complete;
urb->number_of_packets = npackets;
urb->transfer_buffer_length = size;
@@ -671,20 +707,15 @@ static int uvc_init_video_bulk(struct uv
if (size > psize * UVC_MAX_ISO_PACKETS)
size = psize * UVC_MAX_ISO_PACKETS;

+ if (uvc_alloc_urb_buffers(video, size) < 0)
+ return -ENOMEM;
+
pipe = usb_rcvbulkpipe(video->dev->udev, ep->desc.bEndpointAddress);

for (i = 0; i < UVC_URBS; ++i) {
urb = usb_alloc_urb(0, gfp_flags);
if (urb == NULL) {
- uvc_uninit_video(video);
- return -ENOMEM;
- }
-
- video->urb_buffer[i] = usb_buffer_alloc(video->dev->udev,
- size, gfp_flags, &urb->transfer_dma);
- if (video->urb_buffer[i] == NULL) {
- usb_free_urb(urb);
- uvc_uninit_video(video);
+ uvc_uninit_video(video, 1);
return -ENOMEM;
}

@@ -692,6 +723,7 @@ static int uvc_init_video_bulk(struct uv
video->urb_buffer[i], size, uvc_video_complete,
video);
urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
+ urb->transfer_dma = video->urb_dma[i];

video->urb[i] = urb;
}
@@ -766,7 +798,7 @@ static int uvc_init_video(struct uvc_vid
if ((ret = usb_submit_urb(video->urb[i], gfp_flags)) < 0) {
uvc_printk(KERN_ERR, "Failed to submit URB %u "
"(%d).\n", i, ret);
- uvc_uninit_video(video);
+ uvc_uninit_video(video, 1);
return ret;
}
}
@@ -791,7 +823,7 @@ int uvc_video_suspend(struct uvc_video_d
return 0;

video->frozen = 1;
- uvc_uninit_video(video);
+ uvc_uninit_video(video, 0);
usb_set_interface(video->dev->udev, video->streaming->intfnum, 0);
return 0;
}
@@ -920,7 +952,7 @@ int uvc_video_enable(struct uvc_video_de
int ret;

if (!enable) {
- uvc_uninit_video(video);
+ uvc_uninit_video(video, 1);
usb_set_interface(video->dev->udev,
video->streaming->intfnum, 0);
uvc_queue_enable(&video->queue, 0);
--- a/drivers/media/video/uvc/uvcvideo.h
+++ b/drivers/media/video/uvc/uvcvideo.h
@@ -602,6 +602,8 @@ struct uvc_video_device {

struct urb *urb[UVC_URBS];
char *urb_buffer[UVC_URBS];
+ dma_addr_t urb_dma[UVC_URBS];
+ unsigned int urb_size;

__u8 last_fid;
};
--


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