[PATCH 06/11] drivers/acpi/apei: convert seqno counter_atomic32

Shuah Khan
2020-09-25T23:47:50Z

counter_atomic* is introduced to be used when a variable is used as
a simple counter and doesn't guard object lifetimes. This clearly
differentiates atomic_t usages that guard object lifetimes.

counter_atomic* variables will wrap around to 0 when it overflows and
should not be used to guard resource lifetimes, device usage and
open counts that control state changes, and pm states.

seqno is a sequence number counter for logging. This counter gets
incremented. Unsure if there is a chance of this overflowing. It
doesn't look like overflowing causes any problems since it is used
to tag the log messages and nothing more.

Convert it to use counter_atomic32.

This conversion doesn't change the overflow wrap around behavior.

Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
---
drivers/acpi/apei/ghes.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 81bf71b10d44..92169436be18 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -41,6 +41,7 @@
#include <linux/uuid.h>
#include <linux/ras.h>
#include <linux/task_work.h>
+#include <linux/counters.h>

#include <acpi/actbl1.h>
#include <acpi/ghes.h>
@@ -562,7 +563,7 @@ static void __ghes_print_estatus(const char *pfx,
const struct acpi_hest_generic *generic,
const struct acpi_hest_generic_status *estatus)
{
- static atomic_t seqno;
+ static struct counter_atomic32 seqno = COUNTER_ATOMIC_INIT(0);
unsigned int curr_seqno;
char pfx_seq[64];

@@ -573,7 +574,7 @@ static void __ghes_print_estatus(const char *pfx,
else
pfx = KERN_ERR;
}
- curr_seqno = atomic_inc_return(&seqno);
+ curr_seqno = counter_atomic32_inc_return(&seqno);
snprintf(pfx_seq, sizeof(pfx_seq), "%s{%u}" HW_ERR, pfx, curr_seqno);
printk("%s""Hardware error from APEI Generic Hardware Error Source: %d\n",
pfx_seq, generic->header.source_id);
--
2.25.1