From: Hans Verkuil <hverkuil-cisco@xs4all.nl>
To: helen.koike@collabora.com
Cc: Shuah Khan <skhan@linuxfoundation.org>,
linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/2] Use Media Dev Allocator to fix vimc dev lifetime bugs
Date: Thu, 13 Jun 2019 07:44:15 +0200 [thread overview]
Message-ID: <c9160fe7-e880-4070-3959-b9e9177acf54@xs4all.nl> (raw)
In-Reply-To: <cover.1558667245.git.skhan@linuxfoundation.org>
On 5/24/19 5:31 AM, Shuah Khan wrote:
> media_device is embedded in struct vimc_device and when vimc is removed
> vimc_device and the embedded media_device goes with it, while the active
> stream and vimc_capture continue to access it.
>
> Fix the media_device lifetime problem by changing vimc to create shared
> media_device using Media Device Allocator API and vimc_capture getting
> a reference to vimc module. With this change, vimc module can be removed
> only when the references are gone. vimc can be removed after vimc_capture
> is removed.
>
> Media Device Allocator API supports just USB devices. Enhance it
> adding a genetic device allocate interface to support other media
> drivers.
>
> The new interface takes pointer to struct device instead and creates
> media device. This interface allows a group of drivers that have a
> common root device to share media device resource and ensure media
> device doesn't get deleted as long as one of the drivers holds its
> reference.
>
> The new interface has been tested with vimc component driver to fix
> panics when vimc module is removed while streaming is in progress.
Helen, can you review this series? I'm not sure this is the right approach
for a driver like vimc, and even if it is, then it is odd that vimc-capture
is the only vimc module that's handled here.
My gut feeling is that this should be handled inside vimc directly and not
using the media-dev-allocator.
Regards,
Hans
>
> Shuah Khan (2):
> media: add generic device allocate interface to media-dev-allocator
> vimc: fix BUG: unable to handle kernel NULL pointer dereference
>
> drivers/media/Makefile | 4 +-
> drivers/media/media-dev-allocator.c | 39 ++++++++++++++
> drivers/media/platform/vimc/vimc-capture.c | 17 +++++-
> drivers/media/platform/vimc/vimc-core.c | 60 ++++++++++++----------
> include/media/media-dev-allocator.h | 46 ++++++++++++++---
> 5 files changed, 130 insertions(+), 36 deletions(-)
>
next prev parent reply other threads:[~2019-06-13 16:46 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-24 3:31 [PATCH 0/2] Use Media Dev Allocator to fix vimc dev lifetime bugs Shuah Khan
2019-05-24 3:31 ` [PATCH 1/2] media: add generic device allocate interface to media-dev-allocator Shuah Khan
2019-05-24 3:31 ` [PATCH 2/2] vimc: fix BUG: unable to handle kernel NULL pointer dereference Shuah Khan
2019-06-13 5:44 ` Hans Verkuil [this message]
2019-06-13 13:24 ` [PATCH 0/2] Use Media Dev Allocator to fix vimc dev lifetime bugs Helen Koike
2019-06-14 23:26 ` Shuah Khan
2019-06-16 18:45 ` Laurent Pinchart
2019-06-28 16:41 ` Shuah Khan
2019-06-30 11:41 ` Laurent Pinchart
2019-07-03 16:17 ` Niklas Söderlund
2019-07-03 16:52 ` Shuah Khan
2019-07-03 23:25 ` Laurent Pinchart
2019-07-03 23:42 ` Shuah Khan
2019-06-16 18:43 ` Laurent Pinchart
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