Messages in this thread | | | Date | Mon, 18 Aug 2008 22:46:43 -0700 | From | Andrew Morton <> | Subject | Re: [PATH -mm] Fix a race condtion of oops_in_progress |
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On Tue, 19 Aug 2008 13:38:00 +0800 Huang Ying <ying.huang@intel.com> wrote:
> On Mon, 2008-08-18 at 21:06 -0700, Andrew Morton wrote: > > On Mon, 18 Aug 2008 10:03:27 +0800 Huang Ying <ying.huang@intel.com> wrote: > > > > > This patch fix a race condition of oops_in_progress. Which may be > > > changed on multiple CPU simultaneously, but it is changed via > > > non-atomic operation ++/--. This patch changes the definition of > > > oops_in_process from int to atomic_t, and accessing method to atomic > > > operations. > > > > > > > extern atomic_t oops_in_progress; > > > > In file included from include/asm/system.h:10, > > from include/asm/processor.h:17, > > from include/asm/atomic_32.h:5, > > from include/asm/atomic.h:2, > > from include/linux/crypto.h:20, > > from arch/x86/kernel/asm-offsets_32.c:7, > > from arch/x86/kernel/asm-offsets.c:2: > > include/linux/kernel.h:236: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'oops_in_progress' > > make[1]: *** [arch/x86/kernel/asm-offsets.s] Error 1 > > make: *** [prepare0] Error 2 > > > > we can't inlude asm/atomic.h from linux/kernel.h because asm/atomic.h > > includes linux/kernel.h via the above route. > > > > And we cannot forward-declare atomic_t by hand because it's a typedef. > > > > Not sure what to do, really. Find a different header file in which to > > declare oops_in_progress? > > It seems that asm/atomic.h is used for both atomic_t declaration and > implementation, how about separate them? That it, add a new file > asm/atomic_def.h, put typedef there, and include asm/atomic_def.h in > kernel.h?
yup, that sounds sensible.
Of course, it may be the case that we no longer need to include kernel.h from within asm-x86/system.h. But that's the sort of thing which once done is awfully hard to undo.
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