From bc0e17f691085315ae9303eb5b0883fe16dfe6b1 Mon Sep 17 00:00:00 2001 From: Vasu Dev Date: Fri, 27 Feb 2009 10:54:57 -0800 Subject: [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 Signed-off-by: Robert Love Signed-off-by: James Bottomley --- include/scsi/libfc.h | 12 ++---------- 1 file changed, 2 insertions(+), 10 deletions(-) (limited to 'include/scsi') diff --git a/include/scsi/libfc.h b/include/scsi/libfc.h index 042f4ade73d..b9e6c1cd891 100644 --- a/include/scsi/libfc.h +++ b/include/scsi/libfc.h @@ -68,9 +68,6 @@ /* * FC HBA status */ -#define FC_PAUSE (1 << 1) -#define FC_LINK_UP (1 << 0) - enum fc_lport_state { LPORT_ST_NONE = 0, LPORT_ST_FLOGI, @@ -603,7 +600,8 @@ struct fc_lport { /* Operational Information */ struct libfc_function_template tt; - u16 link_status; + u8 link_up; + u8 qfull; enum fc_lport_state state; unsigned long boot_time; @@ -703,12 +701,6 @@ void fc_linkup(struct fc_lport *); */ void fc_linkdown(struct fc_lport *); -/* - * Pause and unpause traffic. - */ -void fc_pause(struct fc_lport *); -void fc_unpause(struct fc_lport *); - /* * Configure the local port. */ -- cgit v1.2.3-70-g09d2