On Mon, May 19, 2014 at 3:39 PM, Davidlohr Bueso <davidlohr@xxxxxx> wrote: > On Mon, 2014-05-19 at 14:47 -0700, Davidlohr Bueso wrote: >> Andrew had put this patch in -next for a while, and Stephen Rothwell was >> able to trigger some warnings: https://lkml.org/lkml/2014/5/19/627 >> >> 8<---------------------------------------------------------------- >> From: Davidlohr Bueso <davidlohr@xxxxxx> >> Subject: [PATCH] rwsem: Fix warnings for CONFIG_RWSEM_GENERIC_SPINLOCK >> >> Optimistic spinning is only used by the xadd variant >> of rw-semaphores. Make sure that we use the old version >> of the __RWSEM_INITIALIZER macro for systems that rely >> on the spinlock one, otherwise warnings can be triggered, >> such as the following reported on an arm box: >> >> ipc/ipcns_notifier.c:22:8: warning: excess elements in struct initializer [enabled by default] >> ipc/ipcns_notifier.c:22:8: warning: (near initialization for 'ipcns_chain.rwsem') [enabled by default] >> ipc/ipcns_notifier.c:22:8: warning: excess elements in struct initializer [enabled by default] >> ipc/ipcns_notifier.c:22:8: warning: (near initialization for 'ipcns_chain.rwsem') [enabled by default] >> >> Signed-off-by: Davidlohr Bueso <davidlohr@xxxxxx> >> --- >> include/linux/rwsem.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h >> index 3e108f1..091d993 100644 >> --- a/include/linux/rwsem.h >> +++ b/include/linux/rwsem.h >> @@ -64,7 +64,7 @@ static inline int rwsem_is_locked(struct rw_semaphore *sem) >> # define __RWSEM_DEP_MAP_INIT(lockname) >> #endif >> >> -#ifdef CONFIG_SMP >> +#if defined(CONFIG_SMP) && defined(CONFIG_RWSEM_XCHGADD_ALGORITHM) > > Of course, we can also use the following. I have no preference. > > #if defined(CONFIG_SMP) && !defined(CONFIG_RWSEM_GENERIC_SPINLOCK) So if given the choice between the 2, I think checking !CONFIG_RWSEM_GENERIC_SPINLOCK is better just because we use that to decide the implementation/structure layout. Jason -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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