linux/include
Vasu Dev bc0e17f691 [SCSI] libfc, fcoe: fixed locking issues with lport->lp_mutex around lport->link_status
The fcoe_xmit could call fc_pause in case the pending skb queue len is larger
than FCOE_MAX_QUEUE_DEPTH, the fc_pause was trying to grab lport->lp_muex to
change lport->link_status and that had these issues :-

1. The fcoe_xmit was getting called with bh disabled, thus causing
"BUG: scheduling while atomic" when grabbing lport->lp_muex with bh disabled.

2. fc_linkup and fc_linkdown function calls lport_enter function with
lport->lp_mutex held and these enter function in turn calls fcoe_xmit to send
lport related FC frame, e.g. fc_linkup => fc_lport_enter_flogi to send flogi
req. In this case grabbing the same lport->lp_mutex again in fc_puase from
fcoe_xmit would cause deadlock.

The lport->lp_mutex was used for setting FC_PAUSE in fcoe_xmit path but
FC_PAUSE bit was not used anywhere beside just setting and clear this
bit in lport->link_status, instead used a separate field qfull in fc_lport
to eliminate need for lport->lp_mutex to track pending queue full condition
and in turn avoid above described two locking issues.

Also added check for lp->qfull in fc_fcp_lport_queue_ready to trigger
SCSI_MLQUEUE_HOST_BUSY when lp->qfull is set to prevent more scsi-ml cmds
while lp->qfull is set.

This patch eliminated FC_LINK_UP and FC_PAUSE and instead used dedicated
fields in fc_lport for this, this simplified all related conditional
code.

Also removed fc_pause and fc_unpause functions and instead used newly added
lport->qfull directly in fcoe.

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>
2009-03-06 15:37:49 -06:00
..
acpi ACPI: Enable bit 11 in _PDC to advertise hw coord 2009-02-07 00:41:14 -05:00
asm-arm
asm-frv FRV: __pte_to_swp_entry doesn't expand correctly 2009-02-17 14:05:30 -08:00
asm-generic Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-01-26 09:47:28 -08:00
asm-h8300
asm-m32r byteorder: make swab.h include asm/swab.h like a regular header 2009-01-14 19:56:50 -08:00
asm-mn10300 byteorder: make swab.h include asm/swab.h like a regular header 2009-01-14 19:56:50 -08:00
crypto crypto: shash - Fix tfm destruction 2009-02-05 16:51:25 +11:00
drm drm: disable encoders before re-routing them 2009-02-25 14:42:23 +10:00
keys
linux Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-03-03 14:33:20 -08:00
math-emu
media Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6 2009-02-02 19:26:06 -08:00
mtd headers_check fix: mtd/inftl-user.h 2009-01-31 00:13:34 +05:30
net netfilter: nf_conntrack: don't try to deliver events for untracked connections 2009-02-18 15:30:34 +01:00
pcmcia
rdma
rxrpc
scsi [SCSI] libfc, fcoe: fixed locking issues with lport->lp_mutex around lport->link_status 2009-03-06 15:37:49 -06:00
sound headers_check fix: sound/hdsp.h 2009-01-31 00:13:56 +05:30
trace
video atyfb: fix CONFIG_ namespace violations 2009-02-05 12:56:48 -08:00
xen
Kbuild