From 5e02c74905cb00184b6c5ae70b1c1bfae5b3bd17 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Fri, 24 Feb 2023 11:02:37 +0100 Subject: s390/cpum_sf: use READ_ONCE_ALIGNED_128() instead of 128-bit cmpxchg Use READ_ONCE_ALIGNED_128() to read the previous value in front of a 128-bit cmpxchg loop, instead of (mis-)using a 128-bit cmpxchg operation to do the same. This makes the code more readable and is faster. Link: https://lore.kernel.org/r/20230224100237.3247871-3-hca@linux.ibm.com Signed-off-by: Heiko Carstens --- arch/s390/kernel/perf_cpum_sf.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) (limited to 'arch/s390/kernel') diff --git a/arch/s390/kernel/perf_cpum_sf.c b/arch/s390/kernel/perf_cpum_sf.c index 79904a839fb9..e7b867e2f73f 100644 --- a/arch/s390/kernel/perf_cpum_sf.c +++ b/arch/s390/kernel/perf_cpum_sf.c @@ -1355,8 +1355,7 @@ static void hw_perf_event_update(struct perf_event *event, int flush_all) num_sdb++; /* Reset trailer (using compare-double-and-swap) */ - /* READ_ONCE() 16 byte header */ - prev.val = __cdsg(&te->header.val, 0, 0); + prev.val = READ_ONCE_ALIGNED_128(te->header.val); do { old.val = prev.val; new.val = prev.val; @@ -1558,8 +1557,7 @@ static bool aux_set_alert(struct aux_buffer *aux, unsigned long alert_index, struct hws_trailer_entry *te; te = aux_sdb_trailer(aux, alert_index); - /* READ_ONCE() 16 byte header */ - prev.val = __cdsg(&te->header.val, 0, 0); + prev.val = READ_ONCE_ALIGNED_128(te->header.val); do { old.val = prev.val; new.val = prev.val; @@ -1637,8 +1635,7 @@ static bool aux_reset_buffer(struct aux_buffer *aux, unsigned long range, idx_old = idx = aux->empty_mark + 1; for (i = 0; i < range_scan; i++, idx++) { te = aux_sdb_trailer(aux, idx); - /* READ_ONCE() 16 byte header */ - prev.val = __cdsg(&te->header.val, 0, 0); + prev.val = READ_ONCE_ALIGNED_128(te->header.val); do { old.val = prev.val; new.val = prev.val; -- cgit v1.2.3-58-ga151