On 3/9/2012 2:49 PM, Robert Love wrote:
From: Neil Horman<nhorman@xxxxxxxxxxxxx>
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:
[<ffffffff81069c67>] ? warn_slowpath_common+0x87/0xc0
[<ffffffff81069cba>] ? warn_slowpath_null+0x1a/0x20
[<ffffffff8107216d>] ? local_bh_enable+0x7d/0xb0
[<ffffffff81433567>] ? dev_queue_xmit+0x177/0x6c0
[<ffffffffa0293a34>] ? vlan_dev_hwaccel_hard_start_xmit+0x84/0xb0 [8021q]
[<ffffffff8142f46c>] ? dev_hard_start_xmit+0x2bc/0x3f0
[<ffffffff8143392e>] ? dev_queue_xmit+0x53e/0x6c0
[<ffffffff8142348e>] ? __skb_clone+0x2e/0x120
[<ffffffffa02ea83d>] ? fcoe_clean_pending_queue+0xcd/0x100 [libfcoe]
[<ffffffff810559ca>] ? find_busiest_group+0x9aa/0xb20
[<ffffffffa02f7624>] ? fcoe_port_send+0x24/0x50 [fcoe]
[<ffffffffa02f9568>] ? fcoe_xmit+0x228/0x3e0 [fcoe]
[<ffffffffa02c1896>] ? fc_seq_send+0xb6/0x160 [libfc]
[<ffffffffa02c1a76>] ? fc_exch_abort_locked+0x136/0x1c0 [libfc]
[<ffffffffa02c1ca7>] ? fc_exch_mgr_reset+0x147/0x2a0 [libfc]
[<ffffffff814f2c7e>] ? _spin_unlock_irq+0xe/0x20
[<ffffffffa02c91d3>] ? fc_rport_work+0x123/0x5f0 [libfc]
[<ffffffffa02c90b0>] ? fc_rport_work+0x0/0x5f0 [libfc]
[<ffffffff8108b559>] ? worker_thread+0x179/0x2a0
[<ffffffff81090ea0>] ? autoremove_wake_function+0x0/0x40
[<ffffffff8108b3e0>] ? worker_thread+0x0/0x2a0
[<ffffffff81090b56>] ? kthread+0x96/0xa0
[<ffffffff8100c10a>] ? child_rip+0xa/0x20
[<ffffffff81090ac0>] ? kthread+0x0/0xa0
[<ffffffff8100c100>] ? 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<nhorman@xxxxxxxxxxxxx>
Signed-off-by: Robert Love<robert.w.love@xxxxxxxxx>
Robert, This patch is not required based on what we discussed in this
thread..
http://lists.open-fcoe.org/pipermail/devel/2012-February/011946.html
Neil provided "fcoe: Ensure fcoe_recv_frame is always called in process
context" instead of the two patches he submitted initially.
http://lists.open-fcoe.org/pipermail/devel/2012-February/011962.html
Neil, correct me if I'm wrong.
Thanks,
Bhanu
---
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)
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