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>

2 files changed, 66 insertions, 32 deletions

diff --git a/drivers/media/video/uvc/uvc_video.c b/drivers/media/video/uvc/uvc_video.c
index 8eb5748c446e..817af2e36362 100644
--- 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 a995a780db1c..2444b8a9d2a0 100644
--- 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;
 };