Martin Peschke d79ff14262 [SCSI] zfcp: fix lock imbalance by reworking request queue locking ... This patch adds wait_event_interruptible_lock_irq_timeout(), which is a straight-forward descendant of wait_event_interruptible_timeout() and wait_event_interruptible_lock_irq(). The zfcp driver used to call wait_event_interruptible_timeout() in combination with some intricate and error-prone locking. Using wait_event_interruptible_lock_irq_timeout() as a replacement nicely cleans up that locking. This rework removes a situation that resulted in a locking imbalance in zfcp_qdio_sbal_get(): BUG: workqueue leaked lock or atomic: events/1/0xffffff00/10 last function: zfcp_fc_wka_port_offline+0x0/0xa0 [zfcp] It was introduced by commit c2af7545aa "[SCSI] zfcp: Do not wait for SBALs on stopped queue", which had a new code path related to ZFCP_STATUS_ADAPTER_QDIOUP that took an early exit without a required lock being held. The problem occured when a special, non-SCSI I/O request was being submitted in process context, when the adapter's queues had been torn down. In this case the bug surfaced when the Fibre Channel port connection for a well-known address was closed during a concurrent adapter shut-down procedure, which is a rare constellation. This patch also fixes these warnings from the sparse tool (make C=1): drivers/s390/scsi/zfcp_qdio.c:224:12: warning: context imbalance in 'zfcp_qdio_sbal_check' - wrong count at exit drivers/s390/scsi/zfcp_qdio.c:244:5: warning: context imbalance in 'zfcp_qdio_sbal_get' - unexpected unlock Last but not least, we get rid of that crappy lock-unlock-lock sequence at the beginning of the critical section. It is okay to call zfcp_erp_adapter_reopen() with req_q_lock held. Reported-by: Mikulas Patocka <mpatocka@redhat.com> Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Peschke <mpeschke@linux.vnet.ibm.com> Cc: stable@vger.kernel.org #2.6.35+ Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>		2013-08-22 08:53:30 -07:00
..
block	s390/dasd: fix hanging devices after path events	2013-07-30 16:17:25 +02:00
char	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-07-04 11:40:58 -07:00
cio	s390/qdio: remove unused variable	2013-07-16 12:21:57 +02:00
crypto	s390/zcrypt: Alias for new zcrypt device driver base module	2013-07-19 08:37:39 +02:00
kvm	Merge tag 'kvm-3.10-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm	2013-05-05 14:47:31 -07:00
net	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next	2013-07-09 18:24:39 -07:00
scsi	[SCSI] zfcp: fix lock imbalance by reworking request queue locking	2013-08-22 08:53:30 -07:00
Makefile