aoe: update cap on outstanding commands based on config query response

The ATA over Ethernet config query response contains a "buffer count"
field reflecting the AoE target's capacity to buffer incoming AoE
commands.

By taking the current value of this field into accound, we increase
performance throughput or avoid network congestion, when the value
has increased or decreased, respectively.

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>

diff --git a/drivers/block/aoe/aoe.h b/drivers/block/aoe/aoe.h
index d2ed7f18d1acfa6303b67999b0b39a93e575f49b..52f75c097242bd9173a64bb5e03723db056ae839 100644 (file)
--- a/drivers/block/aoe/aoe.h
+++ b/drivers/block/aoe/aoe.h
@@ -122,14 +122,14 @@ struct aoeif {
 
 struct aoetgt {
        unsigned char addr[6];
-       ushort nframes;
+       ushort nframes;         /* cap on frames to use */
        struct aoedev *d;                       /* parent device I belong to */
        struct list_head ffree;                 /* list of free frames */
        struct aoeif ifs[NAOEIFS];
        struct aoeif *ifp;      /* current aoeif in use */
        ushort nout;
-       ushort maxout;
-       ulong falloc;
+       ushort maxout;          /* current value for max outstanding */
+       ulong falloc;           /* number of allocated frames */
        ulong lastwadj;         /* last window adjustment */
        int minbcnt;
        int wpkts, rpkts;

diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c
index 9fe4f1865558abce9ccd7ebf1ee10a56284caf61..a6e95e69296c7a6090e945e91f473753968e9f9b 100644 (file)
--- a/drivers/block/aoe/aoecmd.c
+++ b/drivers/block/aoe/aoecmd.c
@@ -1373,7 +1373,11 @@ aoecmd_cfg_rsp(struct sk_buff *skb)
        spin_lock_irqsave(&d->lock, flags);
 
        t = gettgt(d, h->src);
-       if (!t) {
+       if (t) {
+               t->nframes = n;
+               if (n < t->maxout)
+                       t->maxout = n;
+       } else {
                t = addtgt(d, h->src, n);
                if (!t)
                        goto bail;