From f7059eaa285c0460569ffd26c43ae07e3f03cd6c Mon Sep 17 00:00:00 2001 From: Jean-François Moine Date: Tue, 6 Jul 2010 04:32:27 -0300 Subject: V4L/DVB: gspca - main: Don't use the frame buffer flags MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This patch fixes possible race conditions in queue management with SMP: when a frame was completed, the irq function tried to use the next frame buffer. At this time, it was possible that the application on an other processor updated the frame pointer, making the image to point to a bad buffer. The patch contains two main changes: - the image transfer uses the queue indexes which are protected against simultaneous memory access, - the image pointer which is used for image concatenation is only set at interrupt level. Some subdrivers which used the image pointer have been updated. Reported-by: Hans de Goede Signed-off-by: Jean-François Moine Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/gspca/pac7311.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) (limited to 'drivers/media/video/gspca/pac7311.c') diff --git a/drivers/media/video/gspca/pac7311.c b/drivers/media/video/gspca/pac7311.c index 5568c41a296c..1cb7e99e92bd 100644 --- a/drivers/media/video/gspca/pac7311.c +++ b/drivers/media/video/gspca/pac7311.c @@ -630,12 +630,6 @@ static void sd_pkt_scan(struct gspca_dev *gspca_dev, if (sof) { int n, lum_offset, footer_length; - image = gspca_dev->image; - if (image == NULL) { - gspca_dev->last_packet_type = DISCARD_PACKET; - return; - } - /* 6 bytes after the FF D9 EOF marker a number of lumination bytes are send corresponding to different parts of the image, the 14th and 15th byte after the EOF seem to @@ -651,7 +645,8 @@ static void sd_pkt_scan(struct gspca_dev *gspca_dev, } else { gspca_frame_add(gspca_dev, INTER_PACKET, data, n); } - if (gspca_dev->last_packet_type != DISCARD_PACKET + image = gspca_dev->image; + if (image != NULL && image[gspca_dev->image_len - 2] == 0xff && image[gspca_dev->image_len - 1] == 0xd9) gspca_frame_add(gspca_dev, LAST_PACKET, NULL, 0); -- cgit v1.2.3