Martin Peschke 09c756513a SCSI: zfcp: fix lock imbalance by reworking request queue locking ... commit d79ff14262 upstream. 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> Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2013-08-29 09:50:13 -07:00
..
acpi	Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux	2012-05-05 10:06:06 -07:00
asm-generic	mm: allow arch code to control the user page table ceiling	2013-05-07 19:51:55 -07:00
crypto	crypto: user - Fix lookup of algorithms with IV generator	2012-03-29 19:52:47 +08:00
drm	drm/radeon: add new richland pci ids	2013-05-11 13:48:14 -07:00
keys
linux	SCSI: zfcp: fix lock imbalance by reworking request queue locking	2013-08-29 09:50:13 -07:00
math-emu
media	Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media	2012-05-14 11:23:37 -07:00
misc
mtd
net	ipv6: call udp_push_pending_frames when uncorking a socket with AF_INET pending data	2013-07-28 16:26:02 -07:00
pcmcia
rdma	infiniband: pass rdma_cm module to netlink_dump_start	2012-10-28 10:14:15 -07:00
rxrpc
scsi	SCSI: libsas: fix taskfile corruption in sas_ata_qc_fill_rtf	2012-07-16 09:04:37 -07:00
sound	ALSA: Add a reference counter to card instance	2012-11-17 13:16:13 -08:00
target	target: Add link_magic for fabric allow_link destination target_items	2013-01-21 11:45:24 -08:00
trace	xen/mmu: Use Xen specific TLB flush instead of the generic one.	2012-11-17 13:15:54 -08:00
video	atmel_lcdfb: fix 16-bpp modes on older SOCs	2013-03-20 13:05:00 -07:00
xen	xen/blkback: correctly respond to unknown, non-native requests	2013-04-05 10:04:18 -07:00
Kbuild