lkml.org 
[lkml]   [2008]   [Nov]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] Fix kunmap() argument in sg_miter_stop

* Jens Axboe <jens.axboe@oracle.com> wrote:

> On Mon, Nov 17 2008, Jens Axboe wrote:
> > On Mon, Nov 17 2008, Ingo Molnar wrote:
> > >
> > > * Jens Axboe <jens.axboe@oracle.com> wrote:
> > >
> > > > On Mon, Nov 17 2008, Ingo Molnar wrote:
> > > > >
> > > > > * Jens Axboe <jens.axboe@oracle.com> wrote:
> > > > >
> > > > > > +#define kunmap(p) \
> > > > > > + do { \
> > > > > > + struct page *__p; \
> > > > > > + (void) (&__p == &(p)); \
> > > > > > + __kunmap(p); \
> > > > > > + } while (0)
> > > > > > +
> > > > > > +#define kunmap_atomic(a, t) \
> > > > > > + do { \
> > > > > > + void *__p; \
> > > > > > + (void) (&__p == &(a)); \
> > > > > > + __kunmap_atomic(a, t); \
> > > > > > + } while (0)
> > > > >
> > > > > Agreed - but please use the typecheck() primitive. (linux/typecheck.h)
> > > >
> > > > Neat, didn't know about that, thanks.
> > >
> > > and ack on your patch obviously. Feel free to push it via the block
> > > tree straight away, it doesnt collide with anything pending in the x86
> > > tree.
> > >
> > > Acked-by: Ingo Molnar <mingo@elte.hu>
> >
> > The kunmap() bit is easy to do as I mentioned, but the kunmap_atomic()
> > gets a bit more ugly. Lots of users can just be switched to void *
> > types, but some get ugly like:
> >
> > static struct page **shmem_dir_map(struct page *page)
> > return (struct page **)kmap_atomic(page, KM_USER0);
> > }
> >
> > -static inline void shmem_dir_unmap(struct page **dir)
> > +static inline void shmem_dir_unmap(void *dir)
> > {
> > kunmap_atomic(dir, KM_USER0);
> > }
> >
> > and others again like fs/exec.c:remove_arg_zero() would really like to
> > use a char * type since it dereferences it.
> >
> > I think the kunmap_atomic() change it the most needed part of the patch,
> > but I don't think it can come for free (eg, we have to add variable to
> > the above function).
>
> OK, (void *) cast works fine when I fixed it. Here's a normal build diff
> to show approximately how bad it is. I expected it to be worse, so it
> looks quite doable I think.

hm:

32 files changed, 89 insertions(+), 62 deletions(-)

regarding churn it looks a bit like on the high side. OTOH it's
trivial, most of the churn is spread-out in various architectures, and
it can catch real bugs so i'm still acking it.

Could you please send the patch with a full changelog? I've Cc:-ed
Linus and Andrew - please let us know if you think that this too much
churn for -rc6.

Ingo


\
 
 \ /
  Last update: 2008-11-17 10:45    [W:0.048 / U:0.272 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site