This is a note to let you know that I've just added the patch titled
md/raid5: make use of spin_lock_irq over local_irq_disable + spin_lock
to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: md-raid5-make-use-of-spin_lock_irq-over-local_irq_disable-spin_lock.patch and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Mon Apr 9 17:09:24 CEST 2018
From: Julia Cartwright julia@ni.com Date: Fri, 28 Apr 2017 12:41:02 -0500 Subject: md/raid5: make use of spin_lock_irq over local_irq_disable + spin_lock
From: Julia Cartwright julia@ni.com
[ Upstream commit 3d05f3aed5d721c2c77d20288c29ab26c6193ed5 ]
On mainline, there is no functional difference, just less code, and symmetric lock/unlock paths.
On PREEMPT_RT builds, this fixes the following warning, seen by Alexander GQ Gerasiov, due to the sleeping nature of spinlocks.
BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:993 in_atomic(): 0, irqs_disabled(): 1, pid: 58, name: kworker/u12:1 CPU: 5 PID: 58 Comm: kworker/u12:1 Tainted: G W 4.9.20-rt16-stand6-686 #1 Hardware name: Supermicro SYS-5027R-WRF/X9SRW-F, BIOS 3.2a 10/28/2015 Workqueue: writeback wb_workfn (flush-253:0) Call Trace: dump_stack+0x47/0x68 ? migrate_enable+0x4a/0xf0 ___might_sleep+0x101/0x180 rt_spin_lock+0x17/0x40 add_stripe_bio+0x4e3/0x6c0 [raid456] ? preempt_count_add+0x42/0xb0 raid5_make_request+0x737/0xdd0 [raid456]
Reported-by: Alexander GQ Gerasiov gq@redlab-i.ru Tested-by: Alexander GQ Gerasiov gq@redlab-i.ru Signed-off-by: Julia Cartwright julia@ni.com Signed-off-by: Shaohua Li shli@fb.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/md/raid5.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-)
--- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -110,8 +110,7 @@ static inline void unlock_device_hash_lo static inline void lock_all_device_hash_locks_irq(struct r5conf *conf) { int i; - local_irq_disable(); - spin_lock(conf->hash_locks); + spin_lock_irq(conf->hash_locks); for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++) spin_lock_nest_lock(conf->hash_locks + i, conf->hash_locks); spin_lock(&conf->device_lock); @@ -121,9 +120,9 @@ static inline void unlock_all_device_has { int i; spin_unlock(&conf->device_lock); - for (i = NR_STRIPE_HASH_LOCKS; i; i--) - spin_unlock(conf->hash_locks + i - 1); - local_irq_enable(); + for (i = NR_STRIPE_HASH_LOCKS - 1; i; i--) + spin_unlock(conf->hash_locks + i); + spin_unlock_irq(conf->hash_locks); }
/* bio's attached to a stripe+device for I/O are linked together in bi_sector @@ -732,12 +731,11 @@ static bool is_full_stripe_write(struct
static void lock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2) { - local_irq_disable(); if (sh1 > sh2) { - spin_lock(&sh2->stripe_lock); + spin_lock_irq(&sh2->stripe_lock); spin_lock_nested(&sh1->stripe_lock, 1); } else { - spin_lock(&sh1->stripe_lock); + spin_lock_irq(&sh1->stripe_lock); spin_lock_nested(&sh2->stripe_lock, 1); } } @@ -745,8 +743,7 @@ static void lock_two_stripes(struct stri static void unlock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2) { spin_unlock(&sh1->stripe_lock); - spin_unlock(&sh2->stripe_lock); - local_irq_enable(); + spin_unlock_irq(&sh2->stripe_lock); }
/* Only freshly new full stripe normal write stripe can be added to a batch list */
Patches currently in stable-queue which might be from julia@ni.com are
queue-4.9/md-raid5-make-use-of-spin_lock_irq-over-local_irq_disable-spin_lock.patch