Messages in this thread | | | Date | Thu, 21 Dec 2017 14:00:16 -0800 | From | Josh Triplett <> | Subject | Re: [PATCH 2/2] Introduce __cond_lock_err |
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On Thu, Dec 21, 2017 at 02:48:10PM -0700, Ross Zwisler wrote: > On Tue, Dec 19, 2017 at 08:58:23AM -0800, Matthew Wilcox wrote: > > From: Matthew Wilcox <mawilcox@microsoft.com> > > > > The __cond_lock macro expects the function to return 'true' if the lock > > was acquired and 'false' if it wasn't. We have another common calling > > convention in the kernel, which is returning 0 on success and an errno > > on failure. It's hard to use the existing __cond_lock macro for those > > kinds of functions, so introduce __cond_lock_err() and convert the > > two existing users. > > This is much cleaner! One quick issue below. > > > Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> > > --- > > include/linux/compiler_types.h | 2 ++ > > include/linux/mm.h | 9 ++------- > > mm/memory.c | 9 ++------- > > 3 files changed, 6 insertions(+), 14 deletions(-) > > > > diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h > > index 6b79a9bba9a7..ff3c41c78efa 100644 > > --- a/include/linux/compiler_types.h > > +++ b/include/linux/compiler_types.h > > @@ -16,6 +16,7 @@ > > # define __acquire(x) __context__(x,1) > > # define __release(x) __context__(x,-1) > > # define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0) > > +# define __cond_lock_err(x,c) ((c) ? 1 : ({ __acquire(x); 0; })) > ^ > I think we actually want this to return c here ^
Then you want to use ((c) ?: ...), to avoid evaluating c twice.
- Josh Triplett
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