linux/drivers/scsi/libfc
Vasu Dev a0cc1ecc09 [SCSI] libfc: fix a circular locking warning during sending RRQ
Currently the fc_exch_rrq is called with fc_exch's ex_lock held.
The fc_exch_rrq allocates new exch and that requires taking
ex_lock again after EM lock. This locking order causes warning,
see more details on this warning at :-

 http://www.open-fcoe.org/pipermail/devel/2009-July/003251.html

This patch fixes this by dropping the ex_lock before calling
fc_exch_rrq().

The fc_exch_rrq needs to grab ex_lock lock again to schedule
RRQ retry and in the meanwhile fc_exch_reset could occur before
ex_lock is grabbed inside fc_exch_rrq. So to handle this case,
this patch adds additional check to detect fc_exch_reset after
ex_lock acquired and in case the fc_exch_reset occurred then
abandons the RRQ retry and releases the exch.

Signed-off-by: Vasu Dev <vasu.dev@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
2009-07-30 08:50:02 -05:00
..
fc_disc.c libfc: Add runtime debugging with debug_logging module parameter 2009-06-21 11:07:08 -05:00
fc_elsct.c [SCSI] libfc: Fix compilation warnings with allmodconfig 2009-04-27 10:19:31 -05:00
fc_exch.c [SCSI] libfc: fix a circular locking warning during sending RRQ 2009-07-30 08:50:02 -05:00
fc_fcp.c libfc: Add runtime debugging with debug_logging module parameter 2009-06-21 11:07:08 -05:00
fc_frame.c
fc_lport.c libfc: Add runtime debugging with debug_logging module parameter 2009-06-21 11:07:08 -05:00
fc_rport.c libfc: Add runtime debugging with debug_logging module parameter 2009-06-21 11:07:08 -05:00
Makefile