diff options
author | Vasu Dev <vasu.dev@intel.com> | 2009-02-27 10:54:57 -0800 |
---|---|---|
committer | James Bottomley <James.Bottomley@HansenPartnership.com> | 2009-03-06 15:37:49 -0600 |
commit | bc0e17f691085315ae9303eb5b0883fe16dfe6b1 (patch) | |
tree | 53138e80aec810604d4eca4626e4f8df65376ccc /drivers/scsi/libfc/fc_fcp.c | |
parent | a7e84f2b83f17f8f11da34ccef3ba5a862dc0182 (diff) | |
download | op-kernel-dev-bc0e17f691085315ae9303eb5b0883fe16dfe6b1.zip op-kernel-dev-bc0e17f691085315ae9303eb5b0883fe16dfe6b1.tar.gz |
[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>
Diffstat (limited to 'drivers/scsi/libfc/fc_fcp.c')
-rw-r--r-- | drivers/scsi/libfc/fc_fcp.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/scsi/libfc/fc_fcp.c b/drivers/scsi/libfc/fc_fcp.c index 404e63f..f440aac 100644 --- a/drivers/scsi/libfc/fc_fcp.c +++ b/drivers/scsi/libfc/fc_fcp.c @@ -1621,7 +1621,7 @@ out: static inline int fc_fcp_lport_queue_ready(struct fc_lport *lp) { /* lock ? */ - return (lp->state == LPORT_ST_READY) && (lp->link_status & FC_LINK_UP); + return (lp->state == LPORT_ST_READY) && lp->link_up && !lp->qfull; } /** @@ -1890,7 +1890,7 @@ int fc_eh_abort(struct scsi_cmnd *sc_cmd) lp = shost_priv(sc_cmd->device->host); if (lp->state != LPORT_ST_READY) return rc; - else if (!(lp->link_status & FC_LINK_UP)) + else if (!lp->link_up) return rc; spin_lock_irqsave(lp->host->host_lock, flags); |