aoe: failover remote interface based on aoe_deadsecs parameter

The aoe_deadsecs module parameter allows the user to specify a hard limit
on the number of seconds an AoE command can be retransmitted before the
AoE block device is considered to have failed.

Using aoe_deadsecs to determine the time we try using a different remote
interface helps to ensure that the hard limit is not reached before we've
tried to recover by sending to a different remote port.

As a data storage target, the AoE target is unambiguously identified by
its {major, minor} AoE address tuple, and an AoE target can have multiple
MAC addresses.  However, note that "target" in the driver code and
comments means a {major, minor, MAC address} tuple, as in "somewhere to
send packets".

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 3 insertions, 6 deletions

diff --git a/drivers/block/aoe/aoe.h b/drivers/block/aoe/aoe.h
index ffded64dcbeb..d17b72763973 100644
--- a/drivers/block/aoe/aoe.h
+++ b/drivers/block/aoe/aoe.h
@@ -96,7 +96,6 @@ enum {
         TIMERTICK = HZ / 10,
         MINTIMER = HZ >> 2,
         MAXTIMER = HZ << 1,
-        HELPWAIT = 20,
 };
 
 struct buf {
diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c
index bbab40c8d67c..e3291dfa7607 100644
--- a/drivers/block/aoe/aoecmd.c
+++ b/drivers/block/aoe/aoecmd.c
@@ -633,11 +633,9 @@ rexmit_timer(ulong vp)
                 list_del(pos);
 
                 t = f->t;
-                if (n > HELPWAIT) {
-                        /* see if another target can help */
-                        if (d->ntargets > 1)
-                                d->htgt = t;
-                }
+                if (n > aoe_deadsecs/2)
+                        d->htgt = t; /* see if another target can help */
+
                 if (t->nout == t->maxout) {
                         if (t->maxout > 1)
                                 t->maxout--;