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| author |   Vasily Gorbik <gor@linux.ibm.com> | 2018-07-13 08:13:13 +0200 |
|---|---|---|
| committer |   Martin Schwidefsky <schwidefsky@de.ibm.com> | 2018-07-16 15:45:41 +0200 |
| commit | ac4c4fc87d6beb6dd8287f24670e5e81c24b1de7 (patch) | |
| tree | d6306145ff1baaaf3c0c134006ad24116ff9f1cd | |
| parent | s390/crypto: fix gcc 8 stringop-truncation warning (diff) | |
| download | linux-dev-ac4c4fc87d6beb6dd8287f24670e5e81c24b1de7.tar.xz linux-dev-ac4c4fc87d6beb6dd8287f24670e5e81c24b1de7.zip | |
s390/cmm: avoid add_timer on concurrently used timer
cmm_set_timer could be called concurrently from cmm_thread, cmm proc
handler, upon cmm smsg receive and timer function itself. To avoid
potential race condition and hitting BUG_ON in add_timer on already
pending timer simply reuse mod_timer which is according to
documentation "the only safe way to modify the timeout" with multiple
unserialized concurrent users. mod_timer can handle both active and
inactive timers which allows to carry out minor code simplification as
well.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
| -rw-r--r-- | arch/s390/mm/cmm.c | 7 |
1 files changed, 1 insertions, 6 deletions
diff --git a/arch/s390/mm/cmm.c b/arch/s390/mm/cmm.c index 50d8d1c887a4..510a18299196 100644 --- a/arch/s390/mm/cmm.c +++ b/arch/s390/mm/cmm.c @@ -191,12 +191,7 @@ static void cmm_set_timer(void) del_timer(&cmm_timer); return; } - if (timer_pending(&cmm_timer)) { - if (mod_timer(&cmm_timer, jiffies + cmm_timeout_seconds*HZ)) - return; - } - cmm_timer.expires = jiffies + cmm_timeout_seconds*HZ; - add_timer(&cmm_timer); + mod_timer(&cmm_timer, jiffies + cmm_timeout_seconds * HZ); } static void cmm_timer_fn(struct timer_list *unused) |