From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robert Love Subject: [PATCH 01/10] fcoe: avoid getting into dev_queue_xmit with bottom halves disabled Date: Fri, 09 Mar 2012 14:49:43 -0800 Message-ID: <20120309224942.6515.83069.stgit@localhost6.localdomain6> References: <20120309224937.6515.83801.stgit@localhost6.localdomain6> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: Received: from mga09.intel.com ([134.134.136.24]:51952 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757400Ab2CIWtn (ORCPT ); Fri, 9 Mar 2012 17:49:43 -0500 In-Reply-To: <20120309224937.6515.83801.stgit@localhost6.localdomain6> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: linux-scsi@vger.kernel.org Cc: Neil Horman From: Neil Horman Recieved this warning recently: WARNING: at kernel/softirq.c:143 local_bh_enable+0x7d/0xb0() (Not tainted) Hardware name: C6100 Modules linked in: autofs4 bnx2fc cnic uio fcoe libfcoe libfc scsi_transport_fc scsi_tgt 8021q garp stp llc sunrpc cpufreq_ondemand acpi_cpufreq freq_table mperf ipv6 ixgbe mdio igb dcdbas microcode i2c_i801 i2c_core sg iTCO_wdt iTCO_vendor_support ioatdma dca i7core_edac edac_core shpchp ext4 mbcache jbd2 sd_mod crc_t10dif ahci dm_mirror dm_region_hash dm_log dm_mod [last unloaded: scsi_wait_scan] Pid: 4926, comm: fc_rport_eq Not tainted 2.6.32 #2 Call Trace: [] ? warn_slowpath_common+0x87/0xc0 [] ? warn_slowpath_null+0x1a/0x20 [] ? local_bh_enable+0x7d/0xb0 [] ? dev_queue_xmit+0x177/0x6c0 [] ? vlan_dev_hwaccel_hard_start_xmit+0x84/0xb0 [8021q] [] ? dev_hard_start_xmit+0x2bc/0x3f0 [] ? dev_queue_xmit+0x53e/0x6c0 [] ? __skb_clone+0x2e/0x120 [] ? fcoe_clean_pending_queue+0xcd/0x100 [libfcoe] [] ? find_busiest_group+0x9aa/0xb20 [] ? fcoe_port_send+0x24/0x50 [fcoe] [] ? fcoe_xmit+0x228/0x3e0 [fcoe] [] ? fc_seq_send+0xb6/0x160 [libfc] [] ? fc_exch_abort_locked+0x136/0x1c0 [libfc] [] ? fc_exch_mgr_reset+0x147/0x2a0 [libfc] [] ? _spin_unlock_irq+0xe/0x20 [] ? fc_rport_work+0x123/0x5f0 [libfc] [] ? fc_rport_work+0x0/0x5f0 [libfc] [] ? worker_thread+0x179/0x2a0 [] ? autoremove_wake_function+0x0/0x40 [] ? worker_thread+0x0/0x2a0 [] ? kthread+0x96/0xa0 [] ? child_rip+0xa/0x20 [] ? kthread+0x0/0xa0 [] ? child_rip+0x0/0x20 fc_exch_abort_locked attempts to send an abort frame, but it does so with a spinlock held and irqs/bh's disabled. Because of this dev_queue_xmit issues a warning. This patch allows the fc_exch_abort_locked to drop and re-acquire the lock so that the warning is suppressed. Note this isn't a great fix, given that we need to free and re-acquire the ex_lock during the fc_exch_abort_locked operation, but any other solution is going to be a fairly major undertaking I think. This should work until a proper fix can be found. Signed-off-by: Neil Horman Signed-off-by: Robert Love --- drivers/scsi/libfc/fc_exch.c | 31 ++++++++++++++++++++++++++----- include/scsi/libfc.h | 1 + 2 files changed, 27 insertions(+), 5 deletions(-) diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c index 630291f..588060f 100644 --- a/drivers/scsi/libfc/fc_exch.c +++ b/drivers/scsi/libfc/fc_exch.c @@ -594,16 +594,23 @@ static int fc_exch_abort_locked(struct fc_exch *ep, struct fc_frame *fp; int error; + if (ep->in_locked_transaction == true) + return -EAGAIN; + + ep->in_locked_transaction = true; + + error = -ENXIO; if (ep->esb_stat & (ESB_ST_COMPLETE | ESB_ST_ABNORMAL) || ep->state & (FC_EX_DONE | FC_EX_RST_CLEANUP)) - return -ENXIO; + goto out; /* * Send the abort on a new sequence if possible. */ + error = -ENOMEM; sp = fc_seq_start_next_locked(&ep->seq); if (!sp) - return -ENOMEM; + goto out; ep->esb_stat |= ESB_ST_SEQ_INIT | ESB_ST_ABNORMAL; if (timer_msec) @@ -613,8 +620,9 @@ static int fc_exch_abort_locked(struct fc_exch *ep, * If not logged into the fabric, don't send ABTS but leave * sequence active until next timeout. */ + error = 0; if (!ep->sid) - return 0; + goto out; /* * Send an abort for the sequence that timed out. @@ -623,9 +631,13 @@ static int fc_exch_abort_locked(struct fc_exch *ep, if (fp) { fc_fill_fc_hdr(fp, FC_RCTL_BA_ABTS, ep->did, ep->sid, FC_TYPE_BLS, FC_FC_END_SEQ | FC_FC_SEQ_INIT, 0); + spin_unlock_bh(&ep->ex_lock); error = fc_seq_send(ep->lp, sp, fp); + spin_lock_bh(&ep->ex_lock); } else error = -ENOBUFS; +out: + ep->in_locked_transaction = false; return error; } @@ -645,9 +657,12 @@ static int fc_seq_exch_abort(const struct fc_seq *req_sp, int error; ep = fc_seq_exch(req_sp); +retry: spin_lock_bh(&ep->ex_lock); error = fc_exch_abort_locked(ep, timer_msec); spin_unlock_bh(&ep->ex_lock); + if (error == -EAGAIN) + goto retry; return error; } @@ -1732,10 +1747,16 @@ static void fc_exch_reset(struct fc_exch *ep) struct fc_seq *sp; void (*resp)(struct fc_seq *, struct fc_frame *, void *); void *arg; - int rc = 1; + int rc; +retry: spin_lock_bh(&ep->ex_lock); - fc_exch_abort_locked(ep, 0); + rc = fc_exch_abort_locked(ep, 0); + if (rc == -EAGAIN) { + spin_unlock_bh(&ep->ex_lock); + goto retry; + } + ep->state |= FC_EX_RST_CLEANUP; if (cancel_delayed_work(&ep->timeout_work)) atomic_dec(&ep->ex_refcnt); /* drop hold for timer */ diff --git a/include/scsi/libfc.h b/include/scsi/libfc.h index 8f9dfba..0a4ceb8 100644 --- a/include/scsi/libfc.h +++ b/include/scsi/libfc.h @@ -438,6 +438,7 @@ struct fc_exch { void (*resp)(struct fc_seq *, struct fc_frame *, void *); void *arg; void (*destructor)(struct fc_seq *, void *); + bool in_locked_transaction; struct delayed_work timeout_work; } ____cacheline_aligned_in_smp; #define fc_seq_exch(sp) container_of(sp, struct fc_exch, seq)