V4L/DVB (8209): 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 presure
on system memory.

Signed-off-by: Laurent Pinchart <laurent.pinchart@skynet.be>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

diff --git a/drivers/media/video/uvc/uvc_video.c b/drivers/media/video/uvc/uvc_video.c
index 8eb5748..817af2e 100644 (file)
--- 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 urb *urb)
 }
 
 /*
+ * 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_video_device *video)
                        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 uvc_video_device *video,
 
        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 uvc_video_device *video,
                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 uvc_video_device *video,
        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 uvc_video_device *video,
                        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_video_device *video, gfp_t gfp_flags)
                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_device *video)
                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_device *video, int enable)
        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);

diff --git a/drivers/media/video/uvc/uvcvideo.h b/drivers/media/video/uvc/uvcvideo.h
index a995a78..2444b8a 100644 (file)
--- 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;
 };