From 1139aeb1c521eb4a050920ce6c64c36c4f2a3ab7 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 5 May 2021 23:12:42 +0200 Subject: smp: Fix smp_call_function_single_async prototype As of commit 966a967116e6 ("smp: Avoid using two cache lines for struct call_single_data"), the smp code prefers 32-byte aligned call_single_data objects for performance reasons, but the block layer includes an instance of this structure in the main 'struct request' that is more senstive to size than to performance here, see 4ccafe032005 ("block: unalign call_single_data in struct request"). The result is a violation of the calling conventions that clang correctly points out: block/blk-mq.c:630:39: warning: passing 8-byte aligned argument to 32-byte aligned parameter 2 of 'smp_call_function_single_async' may result in an unaligned pointer access [-Walign-mismatch] smp_call_function_single_async(cpu, &rq->csd); It does seem that the usage of the call_single_data without cache line alignment should still be allowed by the smp code, so just change the function prototype so it accepts both, but leave the default alignment unchanged for the other users. This seems better to me than adding a local hack to shut up an otherwise correct warning in the caller. Signed-off-by: Arnd Bergmann Signed-off-by: Peter Zijlstra (Intel) Acked-by: Jens Axboe Link: https://lkml.kernel.org/r/20210505211300.3174456-1-arnd@kernel.org --- kernel/up.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/up.c') diff --git a/kernel/up.c b/kernel/up.c index bf20b4a9af60..c7321307923a 100644 --- a/kernel/up.c +++ b/kernel/up.c @@ -25,7 +25,7 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info, } EXPORT_SYMBOL(smp_call_function_single); -int smp_call_function_single_async(int cpu, call_single_data_t *csd) +int smp_call_function_single_async(int cpu, struct __call_single_data *csd) { unsigned long flags; -- cgit v1.2.3