On 8/9/2011 2:20 PM, Vasu Dev wrote:
Current fc_eh_host_reset leaves lport offline
permanently due to FLOGI response getting
handled by LOGO response from last reset as both
had same exchange id.
So fix this by having end to end exches clean-up
using exchange abort along exches reset
done from fc_eh_host_reset. This would avoid
exchanges collision between the sessions across
the reset. In this case implicit login should have
done that but no aborting support for FIP
frames, so just wait till lport->r_a_tov before
restarting next flogi to ensure all exchanges
are good to use again for next session.
Below is the trace of LOGO from older session
coming ahead of FLOGI response with same exche id
0x203:-
617 86.435165 4e.00.0b -> ff.ff.fc FC ELS LOGO 0x203
618 86.435195 4e.00.0b -> b6.02.00 FC ELS LOGO 0x213
619 86.435220 4e.00.0b -> 18.03.00 FC ELS LOGO 0x223
620 86.435244 4e.00.0b -> 18.02.00 FC ELS LOGO 0x233
621 86.435267 4e.00.0b -> 18.01.00 FC ELS LOGO 0x243
622 86.435349 00.00.00 -> ff.ff.fe FC ELS FLOGI 0x203
623 86.435549 ff.ff.fc -> 4e.00.0b FC ELS ACC (LOGO) 0x203
624 86.438721 ff.ff.fe -> 4e.00.0b FC ELS ACC (FLOGI) 0x203
625 86.442059 18.03.00 -> 4e.00.0b FC ELS ACC (LOGO) 0x223
626 86.443683 b6.02.00 -> 4e.00.0b FC ELS ACC (LOGO) 0x213
627 86.447693 18.01.00 -> 4e.00.0b FC ELS ACC (LOGO) 0x243
628 86.453499 18.02.00 -> 4e.00.0b FC ELS ACC (LOGO) 0x233
Signed-off-by: Vasu Dev<[email protected]>
Tested-by: Ross Brattain<[email protected]>
---
I'm seeing a couple side effects with this change
1. r_a_tov delay is present not only when fc_eh_host_reset is called,
but every time the lport is reset, as fc_lport_enter_reset() has the
delay. fc_lport_enter_reset is called from multiple contexts, and some
of them have rtnl_lock() held. Because of this change we now have a
delay of 10 secs whenever an FCoE interface is created.
2. When the FCoE interface is destroyed, we now send a LOGO followed
immediately by ABTS. Although there is no functional problem, it doesn't
look right from protocol point-of-view, as the exchange didn't really
timeout to issue an ABTS.
Can you please elaborate in what circumstances do we see this problem
(apart from what is described)? Is the delay of 10 secs required in all
the scenarios? I'm afraid it may lead to system slowdown as we sleep
with multiple locks held. One such issue is observed when creating
multiple NPIV ports. We also see the system temporarily hangs for 10
secs during the msleep() when the FCoE interface is created.
If this is meant only for fc_eh_host_reset(), can we somehow localize
this fix only to that context?
Thanks,
Bhanu
drivers/scsi/libfc/fc_exch.c | 51 ++++++++++++++++++++++++++++-------------
drivers/scsi/libfc/fc_lport.c | 11 ++++++++-
2 files changed, 45 insertions(+), 17 deletions(-)
diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c
index 01ff082..744fefe 100644
--- a/drivers/scsi/libfc/fc_exch.c
+++ b/drivers/scsi/libfc/fc_exch.c
@@ -494,6 +494,9 @@ static int fc_seq_send(struct fc_lport *lport, struct
fc_seq *sp,
*/
error = lport->tt.frame_send(lport, fp);
+ if (fh->fh_type == FC_TYPE_BLS)
+ return error;
+
/*
* Update the exchange and sequence flags,
* assuming all frames for the sequence have been sent.
@@ -575,42 +578,35 @@ static void fc_seq_set_resp(struct fc_seq *sp,
}
/**
- * fc_seq_exch_abort() - Abort an exchange and sequence
- * @req_sp: The sequence to be aborted
+ * fc_exch_abort_locked() - Abort an exchange
+ * @ep: The exchange to be aborted
* @timer_msec: The period of time to wait before aborting
*
- * Generally called because of a timeout or an abort from the upper layer.
+ * Locking notes: Called with exch lock held
+ *
+ * Return value: 0 on success else error code
*/
-static int fc_seq_exch_abort(const struct fc_seq *req_sp,
- unsigned int timer_msec)
+static int fc_exch_abort_locked(struct fc_exch *ep,
+ unsigned int timer_msec)
{
struct fc_seq *sp;
- struct fc_exch *ep;
struct fc_frame *fp;
int error;
- ep = fc_seq_exch(req_sp);
-
- spin_lock_bh(&ep->ex_lock);
if (ep->esb_stat& (ESB_ST_COMPLETE | ESB_ST_ABNORMAL) ||
- ep->state& (FC_EX_DONE | FC_EX_RST_CLEANUP)) {
- spin_unlock_bh(&ep->ex_lock);
+ ep->state& (FC_EX_DONE | FC_EX_RST_CLEANUP))
return -ENXIO;
- }
/*
* Send the abort on a new sequence if possible.
*/
sp = fc_seq_start_next_locked(&ep->seq);
- if (!sp) {
- spin_unlock_bh(&ep->ex_lock);
+ if (!sp)
return -ENOMEM;
- }
ep->esb_stat |= ESB_ST_SEQ_INIT | ESB_ST_ABNORMAL;
if (timer_msec)
fc_exch_timer_set_locked(ep, timer_msec);
- spin_unlock_bh(&ep->ex_lock);
/*
* If not logged into the fabric, don't send ABTS but leave
@@ -633,6 +629,28 @@ static int fc_seq_exch_abort(const struct fc_seq *req_sp,
}
/**
+ * fc_seq_exch_abort() - Abort an exchange and sequence
+ * @req_sp: The sequence to be aborted
+ * @timer_msec: The period of time to wait before aborting
+ *
+ * Generally called because of a timeout or an abort from the upper layer.
+ *
+ * Return value: 0 on success else error code
+ */
+static int fc_seq_exch_abort(const struct fc_seq *req_sp,
+ unsigned int timer_msec)
+{
+ struct fc_exch *ep;
+ int error;
+
+ ep = fc_seq_exch(req_sp);
+ spin_lock_bh(&ep->ex_lock);
+ error = fc_exch_abort_locked(ep, timer_msec);
+ spin_unlock_bh(&ep->ex_lock);
+ return error;
+}
+
+/**
* fc_exch_timeout() - Handle exchange timer expiration
* @work: The work_struct identifying the exchange that timed out
*/
@@ -1715,6 +1733,7 @@ static void fc_exch_reset(struct fc_exch *ep)
int rc = 1;
spin_lock_bh(&ep->ex_lock);
+ fc_exch_abort_locked(ep, 0);
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/drivers/scsi/libfc/fc_lport.c b/drivers/scsi/libfc/fc_lport.c
index e55ed9c..628f347 100644
--- a/drivers/scsi/libfc/fc_lport.c
+++ b/drivers/scsi/libfc/fc_lport.c
@@ -88,6 +88,7 @@
*/
#include<linux/timer.h>
+#include<linux/delay.h>
#include<linux/slab.h>
#include<asm/unaligned.h>
@@ -1029,8 +1030,16 @@ static void fc_lport_enter_reset(struct fc_lport *lport)
FCH_EVT_LIPRESET, 0);
fc_vports_linkchange(lport);
fc_lport_reset_locked(lport);
- if (lport->link_up)
+ if (lport->link_up) {
+ /*
+ * Wait upto resource allocation time out before
+ * doing re-login since incomplete FIP exchanged
+ * from last session may collide with exchanges
+ * in new session.
+ */
+ msleep(lport->r_a_tov);
fc_lport_enter_flogi(lport);
+ }
}
/**
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