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  1. 19 6月, 2012 1 次提交
  3. 16 5月, 2012 1 次提交
  5. 14 5月, 2012 1 次提交
    • H
      [media] v4l2-dev: add flag to have the core lock all file operations · 5126f259
      由 Hans Verkuil 提交于 
      This used to be the default if the lock pointer was set, but now that lock is by
default only used for ioctl serialization. Those drivers that already used
core locking have this flag set explicitly, except for some drivers where
it was obvious that there was no need to serialize any file operations other
than ioctl.

The drivers that didn't need this flag were:

drivers/media/radio/dsbr100.c
drivers/media/radio/radio-isa.c
drivers/media/radio/radio-keene.c
drivers/media/radio/radio-miropcm20.c
drivers/media/radio/radio-mr800.c
drivers/media/radio/radio-tea5764.c
drivers/media/radio/radio-timb.c
drivers/media/video/vivi.c
sound/i2c/other/tea575x-tuner.c

The other drivers that use core locking and where it was not immediately
obvious that this flag wasn't needed were changed so that the flag is set
together with a comment that that driver needs work to avoid having to
set that flag. This will often involve taking the core lock in the fops
themselves.

Eventually this flag should go and it should not be used in new drivers.

There are a few reasons why we want to avoid core locking of non-ioctl
fops: in the case of mmap this can lead to a deadlock in rare situations
since when mmap is called the mmap_sem is held and it is possible for
other parts of the code to take that lock as well (copy_from_user()/copy_to_user()
perform a down_read(&mm->mmap_sem) when a page fault occurs).

It is very unlikely that that happens since the core lock serializes all
fops, but the kernel warns about it if lock validation is turned on.

For poll it is also undesirable to take the core lock as that can introduce
increased latency. The same is true for read/write.

While it was possible to make flags or something to turn on/off taking the
core lock for each file operation, in practice it is much simpler to just
not take it at all except for ioctl and leave it to the driver to take the
lock. There are only a handful fops compared to the zillion ioctls we have.

I also wanted to make it obvious which drivers still take the lock for all
fops, so that's why I chose to have drivers set it explicitly.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Acked-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>
      5126f259
  7. 04 11月, 2011 1 次提交
  9. 26 9月, 2011 1 次提交
  11. 07 9月, 2011 1 次提交
  13. 28 7月, 2011 1 次提交
    • M
      [media] Stop using linux/version.h on most video drivers · 1990d50b
      由 Mauro Carvalho Chehab 提交于 
      All the modified drivers didn't have any version increment since
Jan, 1 2011. Several of them didn't have any version increment
for a long time, even having new features and important bug fixes
happening.

As we're now filling the QUERYCAP version with the current Kernel
Release, we don't need to maintain a per-driver version control
anymore. So, let's just use the default.

In order to preserve the Kernel module version history, a
KERNEL_VERSION() macro were added to all modified drivers, and
the extraver number were incremented.

I opted to preserve the per-driver version control to a few
pwc, pvrusb2, s2255, s5p-fimc and sh_vou.

A few drivers are still using the legacy way to handle ioctl's.
So, we can't do such change on them, otherwise, they'll break.
Those are: uvc, et61x251 and sn9c102.

The rationale is that the per-driver version control seems to be
actively maintained on those.

Yet, I think that the better for them would be to just use the
default version numbering, instead of doing that by themselves.

While here, removed a few uneeded include linux/version.h
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>
      1990d50b
  15. 22 3月, 2011 2 次提交
  17. 02 2月, 2011 1 次提交
  19. 29 12月, 2010 1 次提交
  21. 21 10月, 2010 1 次提交
  23. 28 9月, 2010 2 次提交
  25. 03 8月, 2010 1 次提交
  27. 09 7月, 2010 1 次提交
  29. 19 5月, 2010 3 次提交