From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx01.qsc.de ([213.148.129.14]:38799 "EHLO mx01.qsc.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751295Ab0CUTJ3 (ORCPT ); Sun, 21 Mar 2010 15:09:29 -0400 Date: Sun, 21 Mar 2010 20:02:45 +0100 From: Andreas Bombe To: Mauro Carvalho Chehab , linux-media@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Greg Kroah-Hartman , devel@driverdev.osuosl.org, Antoine Jacquet , linux-usb@vger.kernel.org Subject: [PATCH] V4L2: Replace loops for finding max buffers in VIDIOC_REQBUFS callbacks Message-ID: <20100321190243.GA4533@amos.infernal> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: linux-media-owner@vger.kernel.org List-ID: Due to obvious copy and paste coding a number of video capture drivers which implement a limit on the buffer memory decremented the user supplied buffer count in a while loop until it reaches an acceptable value. This is a silly thing to do when the maximum value can be directly computed. Signed-off-by: Andreas Bombe --- I tested the looping variants (represented by vivi.c) with large numbers of requested buffers. There was no easily measurable delay on my desktop machine, but still. At least the buffer count isn't 64 bit on any architecture. I think I got them all. These are the files which I grepped as candidates (correct = no loop, unlimited = no limit on buffer count, fixed = in this patch), relative to drivers/media/video: ../common/saa7146_video.c: correct au0828/au0828-video.c: unlimited bt8xx/bttv-driver.c: fixed cx231xx/cx231xx-video.c: unlimited cx23885/cx23885-video.c: fixed cx88/cx88-video.c: fixed davinci/vpfe_capture.c: unlimited davinci/vpif_capture.c: unlimited davinci/vpif_display.c: unlimited em28xx/em28xx-video.c: unlimited mx1_camera.c: fixed mx3_camera.c: correct omap24xxcam.c: fixed pxa_camera.c: fixed s2255drv.c: fixed saa7134/saa7134-core.c: correct sh_mobile_ceu_camera.c: fixed tlg2300/pd-video.c: unlimited vivi.c: fixed zr364xx.c: fixed ../../staging/cx25821/cx25821-video.c: fixed drivers/media/video/bt8xx/bttv-driver.c | 4 ++-- drivers/media/video/cx23885/cx23885-video.c | 4 ++-- drivers/media/video/cx88/cx88-video.c | 4 ++-- drivers/media/video/mx1_camera.c | 4 ++-- drivers/media/video/omap24xxcam.c | 4 ++-- drivers/media/video/pxa_camera.c | 4 ++-- drivers/media/video/s2255drv.c | 4 ++-- drivers/media/video/sh_mobile_ceu_camera.c | 4 ++-- drivers/media/video/vivi.c | 4 ++-- drivers/media/video/zr364xx.c | 4 ++-- drivers/staging/cx25821/cx25821-video.c | 4 ++-- 11 files changed, 22 insertions(+), 22 deletions(-) diff --git a/drivers/media/video/bt8xx/bttv-driver.c b/drivers/media/video/bt8xx/bttv-driver.c index cb46e8f..79af895 100644 --- a/drivers/media/video/bt8xx/bttv-driver.c +++ b/drivers/media/video/bt8xx/bttv-driver.c @@ -1805,8 +1805,8 @@ buffer_setup(struct videobuf_queue *q, unsigned int *count, unsigned int *size) *size = fh->fmt->depth*fh->width*fh->height >> 3; if (0 == *count) *count = gbuffers; - while (*size * *count > gbuffers * gbufsize) - (*count)--; + if (*size * *count > gbuffers * gbufsize) + *count = (gbuffers * gbufsize) / *size; return 0; } diff --git a/drivers/media/video/cx23885/cx23885-video.c b/drivers/media/video/cx23885/cx23885-video.c index 2d3ac8b..543b854 100644 --- a/drivers/media/video/cx23885/cx23885-video.c +++ b/drivers/media/video/cx23885/cx23885-video.c @@ -514,8 +514,8 @@ static int buffer_setup(struct videobuf_queue *q, unsigned int *count, *size = fh->fmt->depth*fh->width*fh->height >> 3; if (0 == *count) *count = 32; - while (*size * *count > vid_limit * 1024 * 1024) - (*count)--; + if (*size * *count > vid_limit * 1024 * 1024) + *count = (vid_limit * 1024 * 1024) / *size; return 0; } diff --git a/drivers/media/video/cx88/cx88-video.c b/drivers/media/video/cx88/cx88-video.c index 48c450f..9c0ca79 100644 --- a/drivers/media/video/cx88/cx88-video.c +++ b/drivers/media/video/cx88/cx88-video.c @@ -561,8 +561,8 @@ buffer_setup(struct videobuf_queue *q, unsigned int *count, unsigned int *size) *size = fh->fmt->depth*fh->width*fh->height >> 3; if (0 == *count) *count = 32; - while (*size * *count > vid_limit * 1024 * 1024) - (*count)--; + if (*size * *count > vid_limit * 1024 * 1024) + *count = (vid_limit * 1024 * 1024) / *size; return 0; } diff --git a/drivers/media/video/mx1_camera.c b/drivers/media/video/mx1_camera.c index c167cc3..d07af13 100644 --- a/drivers/media/video/mx1_camera.c +++ b/drivers/media/video/mx1_camera.c @@ -140,8 +140,8 @@ static int mx1_videobuf_setup(struct videobuf_queue *vq, unsigned int *count, if (!*count) *count = 32; - while (*size * *count > MAX_VIDEO_MEM * 1024 * 1024) - (*count)--; + if (*size * *count > MAX_VIDEO_MEM * 1024 * 1024) + *count = (MAX_VIDEO_MEM * 1024 * 1024) / *size; dev_dbg(icd->dev.parent, "count=%d, size=%d\n", *count, *size); diff --git a/drivers/media/video/omap24xxcam.c b/drivers/media/video/omap24xxcam.c index 142c327..c910e86 100644 --- a/drivers/media/video/omap24xxcam.c +++ b/drivers/media/video/omap24xxcam.c @@ -451,8 +451,8 @@ static int omap24xxcam_vbq_setup(struct videobuf_queue *vbq, unsigned int *cnt, *size = fh->pix.sizeimage; /* accessing fh->cam->capture_mem is ok, it's constant */ - while (*size * *cnt > fh->cam->capture_mem) - (*cnt)--; + if (*size * *cnt > fh->cam->capture_mem) + *cnt = fh->cam->capture_mem / *size; return 0; } diff --git a/drivers/media/video/pxa_camera.c b/drivers/media/video/pxa_camera.c index 322ac4e..520a35b 100644 --- a/drivers/media/video/pxa_camera.c +++ b/drivers/media/video/pxa_camera.c @@ -252,8 +252,8 @@ static int pxa_videobuf_setup(struct videobuf_queue *vq, unsigned int *count, if (0 == *count) *count = 32; - while (*size * *count > vid_limit * 1024 * 1024) - (*count)--; + if (*size * *count > vid_limit * 1024 * 1024) + *count = (vid_limit * 1024 * 1024) / *size; return 0; } diff --git a/drivers/media/video/s2255drv.c b/drivers/media/video/s2255drv.c index fb742f1..b932d28 100644 --- a/drivers/media/video/s2255drv.c +++ b/drivers/media/video/s2255drv.c @@ -702,8 +702,8 @@ static int buffer_setup(struct videobuf_queue *vq, unsigned int *count, if (0 == *count) *count = S2255_DEF_BUFS; - while (*size * (*count) > vid_limit * 1024 * 1024) - (*count)--; + if (*size * *count > vid_limit * 1024 * 1024) + *count = (vid_limit * 1024 * 1024) / *size; return 0; } diff --git a/drivers/media/video/sh_mobile_ceu_camera.c b/drivers/media/video/sh_mobile_ceu_camera.c index fb88c63..d2eb339 100644 --- a/drivers/media/video/sh_mobile_ceu_camera.c +++ b/drivers/media/video/sh_mobile_ceu_camera.c @@ -212,8 +212,8 @@ static int sh_mobile_ceu_videobuf_setup(struct videobuf_queue *vq, *count = 2; if (pcdev->video_limit) { - while (PAGE_ALIGN(*size) * *count > pcdev->video_limit) - (*count)--; + if (PAGE_ALIGN(*size) * *count > pcdev->video_limit) + *count = pcdev->video_limit / PAGE_ALIGN(*size); } dev_dbg(icd->dev.parent, "count=%d, size=%d\n", *count, *size); diff --git a/drivers/media/video/vivi.c b/drivers/media/video/vivi.c index cdbe703..5a736b8 100644 --- a/drivers/media/video/vivi.c +++ b/drivers/media/video/vivi.c @@ -749,8 +749,8 @@ buffer_setup(struct videobuf_queue *vq, unsigned int *count, unsigned int *size) if (0 == *count) *count = 32; - while (*size * *count > vid_limit * 1024 * 1024) - (*count)--; + if (*size * *count > vid_limit * 1024 * 1024) + *count = (vid_limit * 1024 * 1024) / *size; dprintk(dev, 1, "%s, count=%d, size=%d\n", __func__, *count, *size); diff --git a/drivers/media/video/zr364xx.c b/drivers/media/video/zr364xx.c index 3d4bac2..a82b5bd 100644 --- a/drivers/media/video/zr364xx.c +++ b/drivers/media/video/zr364xx.c @@ -376,8 +376,8 @@ static int buffer_setup(struct videobuf_queue *vq, unsigned int *count, if (*count == 0) *count = ZR364XX_DEF_BUFS; - while (*size * (*count) > ZR364XX_DEF_BUFS * 1024 * 1024) - (*count)--; + if (*size * *count > ZR364XX_DEF_BUFS * 1024 * 1024) + *count = (ZR364XX_DEF_BUFS * 1024 * 1024) / *size; return 0; } diff --git a/drivers/staging/cx25821/cx25821-video.c b/drivers/staging/cx25821/cx25821-video.c index 8cd3986..33d75ab 100644 --- a/drivers/staging/cx25821/cx25821-video.c +++ b/drivers/staging/cx25821/cx25821-video.c @@ -516,8 +516,8 @@ int buffer_setup(struct videobuf_queue *q, unsigned int *count, if (0 == *count) *count = 32; - while (*size * *count > vid_limit * 1024 * 1024) - (*count)--; + if (*size * *count > vid_limit * 1024 * 1024) + *count = (vid_limit * 1024 * 1024) / *size; return 0; } -- 1.7.0.2