linux/drivers/message/fusion
Christoph Hellwig 71e75c97f9 scsi: convert device_busy to atomic_t
Avoid taking the queue_lock to check the per-device queue limit.  Instead
we do an atomic_inc_return early on to grab our slot in the queue,
and if necessary decrement it after finishing all checks.

Unlike the host and target busy counters this doesn't allow us to avoid the
queue_lock in the request_fn due to the way the interface works, but it'll
allow us to prepare for using the blk-mq code, which doesn't use the
queue_lock at all, and it at least avoids a queue_lock round trip in
scsi_device_unbusy, which is still important given how busy the queue_lock
is.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Webb Scales <webbnh@hp.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Tested-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Robert Elliott <elliott@hp.com>
2014-07-25 07:43:45 -04:00
..
lsi SCSI updates for post 3.2 merge window 2012-01-10 10:36:08 -08:00
Kconfig
Makefile message: change to new flag variable 2011-03-17 14:05:34 +01:00
mptbase.c fusion: Add free msg frames to the head, not tail of list 2014-05-28 18:13:24 +02:00
mptbase.h scsi: use 64-bit LUNs 2014-07-17 22:07:37 +02:00
mptctl.c mptfusion: fix msgContext in mptctl_hp_hostinfo 2014-05-28 18:14:16 +02:00
mptctl.h
mptdebug.h [SCSI] mpt fusion: Fixing 1078 data corruption issue for 36GB memory region 2009-06-09 17:21:31 -05:00
mptfc.c scsi: use 64-bit LUNs 2014-07-17 22:07:37 +02:00
mptlan.c [SCSI] mptfusion: Extra debug prints added relavent to Device missing delay error handling 2010-07-28 09:07:47 -05:00
mptlan.h tokenring: delete all remaining driver support 2012-05-15 20:23:16 -04:00
mptsas.c scsi: convert device_busy to atomic_t 2014-07-25 07:43:45 -04:00
mptsas.h [SCSI] mptfusion: Added sanity to check B_T mapping for device before adding to OS 2010-07-27 12:02:32 -05:00
mptscsih.c scsi: use 64-bit LUNs 2014-07-17 22:07:37 +02:00
mptscsih.h scsi: use 64-bit LUNs 2014-07-17 22:07:37 +02:00
mptspi.c fusion: Remove use of DEF_SCSI_QCMD 2014-05-28 18:13:25 +02:00