From: Vasu Dev Date: Fri, 27 Feb 2009 18:54:57 +0000 (-0800) Subject: [SCSI] libfc, fcoe: fixed locking issues with lport->lp_mutex around lport->link_status X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=bc0e17f691085315ae9303eb5b0883fe16dfe6b1;p=linux-2.6-omap-h63xx.git [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 --- diff --git a/drivers/scsi/fcoe/fcoe_sw.c b/drivers/scsi/fcoe/fcoe_sw.c index dc4cd5e2576..cf83675a0fb 100644 --- a/drivers/scsi/fcoe/fcoe_sw.c +++ b/drivers/scsi/fcoe/fcoe_sw.c @@ -116,7 +116,8 @@ static int fcoe_sw_lport_config(struct fc_lport *lp) { int i = 0; - lp->link_status = 0; + lp->link_up = 0; + lp->qfull = 0; lp->max_retry_count = 3; lp->e_d_tov = 2 * 1000; /* FC-FS default */ lp->r_a_tov = 2 * 2 * 1000; @@ -181,9 +182,8 @@ static int fcoe_sw_netdev_config(struct fc_lport *lp, struct net_device *netdev) if (fc_set_mfs(lp, mfs)) return -EINVAL; - lp->link_status = ~FC_PAUSE & ~FC_LINK_UP; if (!fcoe_link_ok(lp)) - lp->link_status |= FC_LINK_UP; + lp->link_up = 1; /* offload features support */ if (fc->real_dev->features & NETIF_F_SG) diff --git a/drivers/scsi/fcoe/libfcoe.c b/drivers/scsi/fcoe/libfcoe.c index e419f486cdb..296071043f5 100644 --- a/drivers/scsi/fcoe/libfcoe.c +++ b/drivers/scsi/fcoe/libfcoe.c @@ -504,7 +504,7 @@ int fcoe_xmit(struct fc_lport *lp, struct fc_frame *fp) if (rc) { fcoe_insert_wait_queue(lp, skb); if (fc->fcoe_pending_queue.qlen > FCOE_MAX_QUEUE_DEPTH) - fc_pause(lp); + lp->qfull = 1; } return 0; @@ -718,7 +718,7 @@ static void fcoe_recv_flogi(struct fcoe_softc *fc, struct fc_frame *fp, u8 *sa) * fcoe_watchdog - fcoe timer callback * @vp: * - * This checks the pending queue length for fcoe and put fcoe to be paused state + * This checks the pending queue length for fcoe and set lport qfull * if the FCOE_MAX_QUEUE_DEPTH is reached. This is done for all fc_lport on the * fcoe_hostlist. * @@ -728,17 +728,17 @@ void fcoe_watchdog(ulong vp) { struct fc_lport *lp; struct fcoe_softc *fc; - int paused = 0; + int qfilled = 0; read_lock(&fcoe_hostlist_lock); list_for_each_entry(fc, &fcoe_hostlist, list) { lp = fc->lp; if (lp) { if (fc->fcoe_pending_queue.qlen > FCOE_MAX_QUEUE_DEPTH) - paused = 1; + qfilled = 1; if (fcoe_check_wait_queue(lp) < FCOE_MAX_QUEUE_DEPTH) { - if (paused) - fc_unpause(lp); + if (qfilled) + lp->qfull = 0; } } } @@ -767,8 +767,7 @@ void fcoe_watchdog(ulong vp) **/ static int fcoe_check_wait_queue(struct fc_lport *lp) { - int rc, unpause = 0; - int paused = 0; + int rc; struct sk_buff *skb; struct fcoe_softc *fc; @@ -776,10 +775,10 @@ static int fcoe_check_wait_queue(struct fc_lport *lp) spin_lock_bh(&fc->fcoe_pending_queue.lock); /* - * is this interface paused? + * if interface pending queue full then set qfull in lport. */ if (fc->fcoe_pending_queue.qlen > FCOE_MAX_QUEUE_DEPTH) - paused = 1; + lp->qfull = 1; if (fc->fcoe_pending_queue.qlen) { while ((skb = __skb_dequeue(&fc->fcoe_pending_queue)) != NULL) { spin_unlock_bh(&fc->fcoe_pending_queue.lock); @@ -791,11 +790,9 @@ static int fcoe_check_wait_queue(struct fc_lport *lp) spin_lock_bh(&fc->fcoe_pending_queue.lock); } if (fc->fcoe_pending_queue.qlen < FCOE_MAX_QUEUE_DEPTH) - unpause = 1; + lp->qfull = 0; } spin_unlock_bh(&fc->fcoe_pending_queue.lock); - if ((unpause) && (paused)) - fc_unpause(lp); return fc->fcoe_pending_queue.qlen; } @@ -873,7 +870,7 @@ static int fcoe_device_notification(struct notifier_block *notifier, struct net_device *real_dev = ptr; struct fcoe_softc *fc; struct fcoe_dev_stats *stats; - u16 new_status; + u32 new_link_up; u32 mfs; int rc = NOTIFY_OK; @@ -890,17 +887,15 @@ static int fcoe_device_notification(struct notifier_block *notifier, goto out; } - new_status = lp->link_status; + new_link_up = lp->link_up; switch (event) { case NETDEV_DOWN: case NETDEV_GOING_DOWN: - new_status &= ~FC_LINK_UP; + new_link_up = 0; break; case NETDEV_UP: case NETDEV_CHANGE: - new_status &= ~FC_LINK_UP; - if (!fcoe_link_ok(lp)) - new_status |= FC_LINK_UP; + new_link_up = !fcoe_link_ok(lp); break; case NETDEV_CHANGEMTU: mfs = fc->real_dev->mtu - @@ -908,17 +903,15 @@ static int fcoe_device_notification(struct notifier_block *notifier, sizeof(struct fcoe_crc_eof)); if (mfs >= FC_MIN_MAX_FRAME) fc_set_mfs(lp, mfs); - new_status &= ~FC_LINK_UP; - if (!fcoe_link_ok(lp)) - new_status |= FC_LINK_UP; + new_link_up = !fcoe_link_ok(lp); break; case NETDEV_REGISTER: break; default: FC_DBG("unknown event %ld call", event); } - if (lp->link_status != new_status) { - if ((new_status & FC_LINK_UP) == FC_LINK_UP) + if (lp->link_up != new_link_up) { + if (new_link_up) fc_linkup(lp); else { stats = lp->dev_stats[smp_processor_id()]; 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); } @@ -606,30 +606,6 @@ 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); } 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. */