[PATCH AUTOSEL 5.4 099/330] s390/cpum_sf: Use kzalloc and minor changes

Sasha Levin
2020-09-18T02:03:16Z

From: Thomas Richter <tmricht@linux.ibm.com>

[ Upstream commit 32dab6828c42f087439d3e2617dc7283546bd8f7 ]

Use kzalloc() to allocate auxiliary buffer structure initialized
with all zeroes to avoid random value in trace output.

Avoid double access to SBD hardware flags.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/s390/kernel/perf_cpum_sf.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/s390/kernel/perf_cpum_sf.c b/arch/s390/kernel/perf_cpum_sf.c
index 229e1e2f8253a..996e447ead3a6 100644
--- a/arch/s390/kernel/perf_cpum_sf.c
+++ b/arch/s390/kernel/perf_cpum_sf.c
@@ -1429,8 +1429,8 @@ static int aux_output_begin(struct perf_output_handle *handle,
idx = aux->empty_mark + 1;
for (i = 0; i < range_scan; i++, idx++) {
te = aux_sdb_trailer(aux, idx);
- te->flags = te->flags & ~SDB_TE_BUFFER_FULL_MASK;
- te->flags = te->flags & ~SDB_TE_ALERT_REQ_MASK;
+ te->flags &= ~(SDB_TE_BUFFER_FULL_MASK |
+ SDB_TE_ALERT_REQ_MASK);
te->overflow = 0;
}
/* Save the position of empty SDBs */
@@ -1477,8 +1477,7 @@ static bool aux_set_alert(struct aux_buffer *aux, unsigned long alert_index,
te = aux_sdb_trailer(aux, alert_index);
do {
orig_flags = te->flags;
- orig_overflow = te->overflow;
- *overflow = orig_overflow;
+ *overflow = orig_overflow = te->overflow;
if (orig_flags & SDB_TE_BUFFER_FULL_MASK) {
/*
* SDB is already set by hardware.
@@ -1712,7 +1711,7 @@ static void *aux_buffer_setup(struct perf_event *event, void **pages,
}

/* Allocate aux_buffer struct for the event */
- aux = kmalloc(sizeof(struct aux_buffer), GFP_KERNEL);
+ aux = kzalloc(sizeof(struct aux_buffer), GFP_KERNEL);
if (!aux)
goto no_aux;
sfb = &aux->sfb;
--
2.25.1