Hi,
Le lundi 29 septembre 2014 à 23:19 +0200, Heinrich Schuchardt a écrit :
> > Gesendet: Montag, 29. September 2014 um 20:03 Uhr
> > Von: "Yann Droneaud" <[email protected]>
> > An: "Heinrich Schuchardt" <[email protected]>
> > Cc: "Greg Kroah-Hartman" <[email protected]>, "Colin Cross"
> > <[email protected]>, "John Stultz" <[email protected]>, "Daniel
> > Vetter" <[email protected]>, "Sumit Semwal" <[email protected]>,
> > "Masanari Iida" <[email protected]>, "Daeseok Youn"
> > <[email protected]>, "Maarten Lankhorst"
> > <[email protected]>, [email protected],
> > [email protected], "Yann Droneaud" <[email protected]>
> > Betreff: Re: [PATCH 1/1] staging : android : sync : get_unused_fd
> >
> > Hi,
> >
> > Le samedi 27 septembre 2014 à 10:52 +0200, Heinrich Schuchardt a écrit :
> > > sync.h recommends to use get_unused_fd which does not set
> > > O_CLOEXEC while the rest of the android tree uses
> > > get_unused_fd_flags and sets O_CLOEXEC.
> > >
> > > The patch adjust the comment.
> > >
> >
> > I'd like to add this patch to my patchset which try to remove
> > get_unused_fd() in favor of get_unused_fd_flags():
> >
> > http://lkml.kernel.org/r/[email protected]
> >
> > But having O_CLOEXEC is welcome but not strictly needed,
> > so I think the patch should be reworked to not require O_CLOEXEC.
>
> All calls to get_unused_fd_flags() in directory drivers/staging/android
> use O_CLOEXEC. That is why I guess it is correct to put it into the
> sync.h comment too.
>
They use O_CLOEXEC because I've suggested it should be a good thing to
do it if possible, and Erik Gilling suggested it would be possible.
So please add a mention to commit 9c6cd3b39048 ('android/sync: use
get_unused_fd_flags(O_CLOEXEC) instead o get_unused_fd()') and commit
45acea57335e ('android/sw_sync: use get_unused_fd_flags(O_CLOEXEC)
instead of get_unused_fd()').
> Your patch set inspired me to look for further usages of get_unused_fd().
I haven't grep through the source nor the documentation, so I failed to
notice this comment. I'm glad you've found it and going to fix it.
> But I think the patch below is valid even if get_unused_fd() should not
> be removed from the kernel.
>
Getting a file descriptor with get_unused_fd_flags(O_CLOEXEC) is not
required to use sync_fence_install(): O_CLOEXEC is only one of the two
values having a meaning for get_unused_fd_flags(), and
sync_fence_install() doesn't care about it.
So I still prefer you use an alternate wording for the comment, so that
it match the behavor of sync_fence_install() and provide advice
regarding O_CLOEXEC usage.
Regards.
> Best regards
>
> Heinrich
>
> >
> > > Signed-off-by: Heinrich Schuchardt <[email protected]>
> > > ---
> > > drivers/staging/android/sync.h | 3 ++-
> > > 1 file changed, 2 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/staging/android/sync.h
> > > b/drivers/staging/android/sync.h
> > > index 66b0f43..a21b79f 100644
> > > --- a/drivers/staging/android/sync.h
> > > +++ b/drivers/staging/android/sync.h
> > > @@ -293,7 +293,8 @@ void sync_fence_put(struct sync_fence *fence);
> > > * @fence: fence to install
> > > * @fd: file descriptor in which to install the fence
> > > *
> > > - * Installs @fence into @fd. @fd's should be acquired through
> > > get_unused_fd().
> > > + * Installs @fence into @fd. @fd's should be acquired through
> > > + * get_unused_fd_flags(O_CLOEXEC).
> >
> > I think it will be better to have something like:
> >
> > get_unused_fd_flags(flags), with flags either provided by userspace
> > or set to O_CLOEXEC.
> >
> >
> > > */
> > > void sync_fence_install(struct sync_fence *fence, int fd);
> > >
--
Yann Droneaud
OPTEYA
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