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authorVasu Dev <vasu.dev@intel.com>2009-02-27 10:54:57 -0800
committerJames Bottomley <James.Bottomley@HansenPartnership.com>2009-03-06 15:37:49 -0600
commitbc0e17f691085315ae9303eb5b0883fe16dfe6b1 (patch)
tree53138e80aec810604d4eca4626e4f8df65376ccc /drivers/scsi/libfc
parenta7e84f2b83f17f8f11da34ccef3ba5a862dc0182 (diff)
[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')
-rw-r--r--drivers/scsi/libfc/fc_fcp.c4
-rw-r--r--drivers/scsi/libfc/fc_lport.c36
2 files changed, 8 insertions, 32 deletions
diff --git a/drivers/scsi/libfc/fc_fcp.c b/drivers/scsi/libfc/fc_fcp.c
index 404e63ff46b..f440aaca39c 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);
diff --git a/drivers/scsi/libfc/fc_lport.c b/drivers/scsi/libfc/fc_lport.c
index 5db223ce3b2..a6ab692f5f5 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);
}