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_lport.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_lport.c')
-rw-r--r-- | drivers/scsi/libfc/fc_lport.c | 36 |
1 files changed, 6 insertions, 30 deletions
diff --git a/drivers/scsi/libfc/fc_lport.c b/drivers/scsi/libfc/fc_lport.c index 5db223c..a6ab692 100644 --- a/drivers/scsi/libfc/fc_lport.c +++ b/drivers/scsi/libfc/fc_lport.c @@ -250,7 +250,7 @@ void fc_get_host_port_state(struct Scsi_Host *shost) { struct fc_lport *lp = shost_priv(shost); - if ((lp->link_status & FC_LINK_UP) == FC_LINK_UP) + if (lp->link_up) fc_host_port_state(shost) = FC_PORTSTATE_ONLINE; else fc_host_port_state(shost) = FC_PORTSTATE_OFFLINE; @@ -577,8 +577,8 @@ void fc_linkup(struct fc_lport *lport) fc_host_port_id(lport->host)); mutex_lock(&lport->lp_mutex); - if ((lport->link_status & FC_LINK_UP) != FC_LINK_UP) { - lport->link_status |= FC_LINK_UP; + if (!lport->link_up) { + lport->link_up = 1; if (lport->state == LPORT_ST_RESET) fc_lport_enter_flogi(lport); @@ -597,8 +597,8 @@ void fc_linkdown(struct fc_lport *lport) FC_DEBUG_LPORT("Link is down for port (%6x)\n", fc_host_port_id(lport->host)); - if ((lport->link_status & FC_LINK_UP) == FC_LINK_UP) { - lport->link_status &= ~(FC_LINK_UP); + if (lport->link_up) { + lport->link_up = 0; fc_lport_enter_reset(lport); lport->tt.fcp_cleanup(lport); } @@ -607,30 +607,6 @@ void fc_linkdown(struct fc_lport *lport) EXPORT_SYMBOL(fc_linkdown); /** - * fc_pause - Pause the flow of frames - * @lport: The lport to be paused - */ -void fc_pause(struct fc_lport *lport) -{ - mutex_lock(&lport->lp_mutex); - lport->link_status |= FC_PAUSE; - mutex_unlock(&lport->lp_mutex); -} -EXPORT_SYMBOL(fc_pause); - -/** - * fc_unpause - Unpause the flow of frames - * @lport: The lport to be unpaused - */ -void fc_unpause(struct fc_lport *lport) -{ - mutex_lock(&lport->lp_mutex); - lport->link_status &= ~(FC_PAUSE); - mutex_unlock(&lport->lp_mutex); -} -EXPORT_SYMBOL(fc_unpause); - -/** * fc_fabric_logoff - Logout of the fabric * @lport: fc_lport pointer to logoff the fabric * @@ -977,7 +953,7 @@ static void fc_lport_enter_reset(struct fc_lport *lport) fc_host_fabric_name(lport->host) = 0; fc_host_port_id(lport->host) = 0; - if ((lport->link_status & FC_LINK_UP) == FC_LINK_UP) + if (lport->link_up) fc_lport_enter_flogi(lport); } |