diff options
author | Vasu Dev <vasu.dev@intel.com> | 2009-02-27 13:54:57 -0500 |
---|---|---|
committer | James Bottomley <James.Bottomley@HansenPartnership.com> | 2009-03-06 16:37:49 -0500 |
commit | bc0e17f691085315ae9303eb5b0883fe16dfe6b1 (patch) | |
tree | 53138e80aec810604d4eca4626e4f8df65376ccc /include/scsi/libfc.h | |
parent | a7e84f2b83f17f8f11da34ccef3ba5a862dc0182 (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 'include/scsi/libfc.h')
-rw-r--r-- | include/scsi/libfc.h | 12 |
1 files changed, 2 insertions, 10 deletions
diff --git a/include/scsi/libfc.h b/include/scsi/libfc.h index 042f4ade73d7..b9e6c1cd8914 100644 --- a/include/scsi/libfc.h +++ b/include/scsi/libfc.h | |||
@@ -68,9 +68,6 @@ | |||
68 | /* | 68 | /* |
69 | * FC HBA status | 69 | * FC HBA status |
70 | */ | 70 | */ |
71 | #define FC_PAUSE (1 << 1) | ||
72 | #define FC_LINK_UP (1 << 0) | ||
73 | |||
74 | enum fc_lport_state { | 71 | enum fc_lport_state { |
75 | LPORT_ST_NONE = 0, | 72 | LPORT_ST_NONE = 0, |
76 | LPORT_ST_FLOGI, | 73 | LPORT_ST_FLOGI, |
@@ -603,7 +600,8 @@ struct fc_lport { | |||
603 | 600 | ||
604 | /* Operational Information */ | 601 | /* Operational Information */ |
605 | struct libfc_function_template tt; | 602 | struct libfc_function_template tt; |
606 | u16 link_status; | 603 | u8 link_up; |
604 | u8 qfull; | ||
607 | enum fc_lport_state state; | 605 | enum fc_lport_state state; |
608 | unsigned long boot_time; | 606 | unsigned long boot_time; |
609 | 607 | ||
@@ -704,12 +702,6 @@ void fc_linkup(struct fc_lport *); | |||
704 | void fc_linkdown(struct fc_lport *); | 702 | void fc_linkdown(struct fc_lport *); |
705 | 703 | ||
706 | /* | 704 | /* |
707 | * Pause and unpause traffic. | ||
708 | */ | ||
709 | void fc_pause(struct fc_lport *); | ||
710 | void fc_unpause(struct fc_lport *); | ||
711 | |||
712 | /* | ||
713 | * Configure the local port. | 705 | * Configure the local port. |
714 | */ | 706 | */ |
715 | int fc_lport_config(struct fc_lport *); | 707 | int fc_lport_config(struct fc_lport *); |