From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Tomasz Figa <tfiga@chromium.org>
Cc: Benjamin Gaignard <benjamin.gaignard@collabora.com>,
m.szyprowski@samsung.com, mchehab@kernel.org, ming.qian@nxp.com,
shijie.qin@nxp.com, eagle.zhou@nxp.com, bin.liu@mediatek.com,
matthias.bgg@gmail.com, angelogioacchino.delregno@collabora.com,
tiffany.lin@mediatek.com, andrew-ct.chen@mediatek.com,
yunfei.dong@mediatek.com, stanimir.k.varbanov@gmail.com,
quic_vgarodia@quicinc.com, agross@kernel.org,
andersson@kernel.org, konrad.dybcio@linaro.org,
ezequiel@vanguardiasur.com.ar, p.zabel@pengutronix.de,
daniel.almeida@collabora.com, hverkuil-cisco@xs4all.nl,
jernel@kernel.org, linux-media@vger.kernel.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-mediatek@lists.infradead.org,
linux-arm-msm@vger.kernel.org,
linux-rockchip@lists.infradead.org, kernel@collabora.com
Subject: Re: [PATCH v2 3/8] media: videobuf2: Add a module param to limit vb2 queue buffer storage
Date: Tue, 30 May 2023 20:38:39 +0300 [thread overview]
Message-ID: <20230530173839.GH22516@pendragon.ideasonboard.com> (raw)
In-Reply-To: <20230519101916.dt25jofubidrasd2@chromium.org>
On Fri, May 19, 2023 at 10:19:16AM +0000, Tomasz Figa wrote:
> On Tue, Mar 21, 2023 at 11:28:50AM +0100, Benjamin Gaignard wrote:
> > Add module parameter "max_vb_buffer_per_queue" to be able to limit
> > the number of vb2 buffers store in queue.
> >
> > Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
> > ---
> > drivers/media/common/videobuf2/videobuf2-core.c | 15 +++------------
> > include/media/videobuf2-core.h | 11 +++++++++--
> > 2 files changed, 12 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
> > index ae9d72f4d181..f4da917ccf3f 100644
> > --- a/drivers/media/common/videobuf2/videobuf2-core.c
> > +++ b/drivers/media/common/videobuf2/videobuf2-core.c
> > @@ -34,6 +34,8 @@
> > static int debug;
> > module_param(debug, int, 0644);
> >
> > +module_param(max_vb_buffer_per_queue, ulong, 0644);
> > +
> > #define dprintk(q, level, fmt, arg...) \
> > do { \
> > if (debug >= level) \
> > @@ -412,10 +414,6 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
> > struct vb2_buffer *vb;
> > int ret;
> >
> > - /* Ensure that q->num_buffers+num_buffers is below VB2_MAX_FRAME */
> > - num_buffers = min_t(unsigned int, num_buffers,
> > - VB2_MAX_FRAME - q->num_buffers);
> > -
>
> We should keep the validation here, just using the new module parameter
> instead of VB2_MAX_FRAME. Otherwise we let the userspace pass
> UINT_MAX to REQBUFS and have the array below exhaust the system memory.
>
> > for (buffer = 0; buffer < num_buffers; ++buffer) {
> > /* Allocate vb2 buffer structures */
> > vb = kzalloc(q->buf_struct_size, GFP_KERNEL);
> > @@ -801,9 +799,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
> > /*
> > * Make sure the requested values and current defaults are sane.
> > */
> > - WARN_ON(q->min_buffers_needed > VB2_MAX_FRAME);
> > num_buffers = max_t(unsigned int, *count, q->min_buffers_needed);
> > - num_buffers = min_t(unsigned int, num_buffers, VB2_MAX_FRAME);
>
> Similar concern here.
>
> > memset(q->alloc_devs, 0, sizeof(q->alloc_devs));
> > /*
> > * Set this now to ensure that drivers see the correct q->memory value
> > @@ -919,11 +915,6 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
> > bool no_previous_buffers = !q->num_buffers;
> > int ret;
> >
> > - if (q->num_buffers == VB2_MAX_FRAME) {
> > - dprintk(q, 1, "maximum number of buffers already allocated\n");
> > - return -ENOBUFS;
> > - }
> > -
>
> Ditto.
>
> > if (no_previous_buffers) {
> > if (q->waiting_in_dqbuf && *count) {
> > dprintk(q, 1, "another dup()ped fd is waiting for a buffer\n");
> > @@ -948,7 +939,7 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
> > return -EINVAL;
> > }
> >
> > - num_buffers = min(*count, VB2_MAX_FRAME - q->num_buffers);
> > + num_buffers = *count;
>
> Ditto.
>
> >
> > if (requested_planes && requested_sizes) {
> > num_planes = requested_planes;
> > diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
> > index 397dbf6e61e1..b8b34a993e04 100644
> > --- a/include/media/videobuf2-core.h
> > +++ b/include/media/videobuf2-core.h
> > @@ -12,6 +12,7 @@
> > #ifndef _MEDIA_VIDEOBUF2_CORE_H
> > #define _MEDIA_VIDEOBUF2_CORE_H
> >
> > +#include <linux/minmax.h>
> > #include <linux/mm_types.h>
> > #include <linux/mutex.h>
> > #include <linux/poll.h>
> > @@ -48,6 +49,8 @@ struct vb2_fileio_data;
> > struct vb2_threadio_data;
> > struct vb2_buffer;
> >
> > +static size_t max_vb_buffer_per_queue = 1024;
> > +
> > /**
> > * struct vb2_mem_ops - memory handling/memory allocator operations.
> > * @alloc: allocate video memory and, optionally, allocator private data,
> > @@ -1268,12 +1271,16 @@ static inline bool vb2_queue_add_buffer(struct vb2_queue *q, struct vb2_buffer *
> >
> > if (vb->index >= q->max_num_bufs) {
> > struct vb2_buffer **tmp;
> > + int cnt = min(max_vb_buffer_per_queue, q->max_num_bufs * 2);
>
> Should cnt also be size_t to match max_vb_buffer_per_queue?
> This could also overflow given q->max_num_bufs big enough, so maybe it
> would just be better to rewrite to?
>
> size_t cnt = (q->max_num_bufs > max_vb_buffer_per_queue / 2) ?
> max_vb_buffer_per_queue : q->max_num_bufs * 2;
>
> Or we could just switch to XArray and it would solve this for us. :)
I like using existing libraries instead of reinventing the wheel :-)
> > +
> > + if (cnt >= q->max_num_bufs)
> > + goto realloc_failed;
> >
> > - tmp = krealloc_array(q->bufs, q->max_num_bufs * 2, sizeof(*q->bufs), GFP_KERNEL);
> > + tmp = krealloc_array(q->bufs, cnt, sizeof(*q->bufs), GFP_KERNEL);
> > if (!tmp)
> > goto realloc_failed;
> >
> > - q->max_num_bufs *= 2;
> > + q->max_num_bufs = cnt;
> > q->bufs = tmp;
> > }
> >
--
Regards,
Laurent Pinchart
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Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip
next prev parent reply other threads:[~2023-05-30 17:38 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-21 10:28 [PATCH v2 0/8] Add DELETE_BUF ioctl Benjamin Gaignard
2023-03-21 10:28 ` [PATCH v2 1/8] media: videobuf2: Access vb2_queue bufs array through helper functions Benjamin Gaignard
2023-03-21 17:42 ` kernel test robot
2023-05-18 10:37 ` Tomasz Figa
2023-03-21 10:28 ` [PATCH v2 2/8] media: videobuf2: Make bufs array dynamic allocated Benjamin Gaignard
2023-03-21 18:16 ` Laurent Pinchart
2023-05-19 10:04 ` Tomasz Figa
2023-03-24 5:01 ` Dan Carpenter
2023-03-24 8:11 ` Benjamin Gaignard
2023-03-24 8:31 ` Hans Verkuil
2023-03-24 8:48 ` Laurent Pinchart
2023-03-24 8:52 ` Hans Verkuil
2023-03-24 8:56 ` Benjamin Gaignard
2023-05-19 10:00 ` Tomasz Figa
2023-03-24 13:02 ` Dmitry Osipenko
2023-03-21 10:28 ` [PATCH v2 3/8] media: videobuf2: Add a module param to limit vb2 queue buffer storage Benjamin Gaignard
2023-03-21 17:01 ` kernel test robot
2023-03-21 19:15 ` kernel test robot
2023-03-22 6:22 ` [EXT] " Ming Qian
2023-05-19 10:19 ` Tomasz Figa
2023-05-30 17:38 ` Laurent Pinchart [this message]
2023-05-31 6:36 ` Hans Verkuil
2023-05-31 8:03 ` Laurent Pinchart
2023-05-31 8:30 ` Hans Verkuil
2023-05-31 12:39 ` Laurent Pinchart
2023-06-01 8:03 ` Benjamin Gaignard
2023-06-01 8:34 ` Laurent Pinchart
2023-06-08 10:24 ` Tomasz Figa
2023-06-08 10:42 ` Laurent Pinchart
2023-03-21 10:28 ` [PATCH v2 4/8] media: videobuf2: Stop define VB2_MAX_FRAME as global Benjamin Gaignard
2023-05-23 7:14 ` Tomasz Figa
2023-03-21 10:28 ` [PATCH v2 5/8] media: v4l2: Add DELETE_BUF ioctl Benjamin Gaignard
2023-03-21 20:06 ` kernel test robot
2023-05-23 8:23 ` Tomasz Figa
2023-03-21 10:28 ` [PATCH v2 6/8] media: v4l2: Add mem2mem helpers for " Benjamin Gaignard
2023-03-21 10:28 ` [PATCH v2 7/8] media: vim2m: Use v4l2-mem2mem helpers for VIDIOC_DELETE_BUF ioctl Benjamin Gaignard
2023-03-21 10:28 ` [PATCH v2 8/8] media: verisilicon: " Benjamin Gaignard
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