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authorArnd Bergmann <arnd@arndb.de>2021-05-05 23:12:42 +0200
committerPeter Zijlstra <peterz@infradead.org>2021-05-06 15:33:49 +0200
commit1139aeb1c521eb4a050920ce6c64c36c4f2a3ab7 (patch)
tree8c78df882fe9a6daac3e0566edb5e1f8bce7fdce /include
parent635de956a7f5a6ffcb04f29d70630c64c717b56b (diff)
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 <arnd@arndb.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Jens Axboe <axboe@kernel.dk> Link: https://lkml.kernel.org/r/20210505211300.3174456-1-arnd@kernel.org
Diffstat (limited to 'include')
-rw-r--r--include/linux/smp.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/smp.h b/include/linux/smp.h
index 84a0b4828f66..f0d3ef654207 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -53,7 +53,7 @@ int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
void *info, bool wait, const struct cpumask *mask);
-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);
/*
* Call a function on all processors