Re: [PATCH 1/2] fs: avoid fdput() after failed fdget() in ksys_sync_file_range()

Luis Chamberlain
2020-05-08T02:21:43Z

On Fri, May 08, 2020 at 01:24:22AM +0100, Al Viro wrote:
> On Fri, May 08, 2020 at 01:05:09AM +0100, Al Viro wrote:
> > On Thu, May 07, 2020 at 05:57:09PM -0600, Shuah Khan wrote:
> > > Fix ksys_sync_file_range() to avoid fdput() after a failed fdget().
> > > fdput() doesn't do fput() on this file since FDPUT_FPUT isn't set
> > > in fd.flags. Fix it anyway since failed fdget() doesn't require
> > > a fdput().
> > >
> > > This was introdcued in a commit to add sync_file_range() helper.
> >
> > Er... What's the point microoptimizing the slow path here?
>
> PS: I'm not saying the patch is incorrect, but Fixes: is IMO over the
> top. And looking at that thing,
> {
> struct fd f = fdget(fd);
> int ret;
>
> if (unlikely(!f.file))
> return -EBADF;
>
> ret = sync_file_range(f.file, offset, nbytes, flags);
> fdput(f);
> return ret;
> }
>
> might be cleaner, but that's a matter of taste...

This makes it easier to read.

Luis