From: Bob Picco <bpicco@redhat.com>
Date: Sun, 22 Aug 2010 19:57:34 -0400
Subject: [net] vxge: fix hw buffer starvation from short packets
Message-id: <20100822195734.24928.65594.sendpatchset@bob-desktop>
Patchwork-id: 27761
O-Subject: [RHEL5.7 PATCH 2/7] vxge: Fix starvation of receive ring controller
	when blasted by short packets.
Bugzilla: 580413
RH-Acked-by: David S. Miller <davem@redhat.com>
RH-Acked-by: Michal Schmidt <mschmidt@redhat.com>
RH-Acked-by: Andy Gospodarek <gospo@redhat.com>

>From 3363276f1c420b7de92169ddabd2bb88aa26a7d6 Mon Sep 17 00:00:00 2001
From: Sreenivasa Honnur <Sreenivasa.Honnur@neterion.com>
Date: Sun, 28 Mar 2010 22:08:30 +0000
Subject: [PATCH 2/7] vxge: Fix starvation of receive ring controller when blasted by short packets.

- Fix starvation of receive ring controller when blasted by short packets. This was because the driver was posting 64 rxds initially while the ring controller
was expecting to read 256 replenished rxds. While the driver was coming up,
the internal rxd memory filled up the 64 buffers provided and the ring
controller was left waiting for the remaining 192 rxds to complete the write
back of completed rxds to the host and generation of an interrupt.

Signed-off-by: Sreenivasa Honnur <sreenivasa.honnur@neterion.com>
Signed-off-by: Ramkrishna Vepa <ram.vepa@neterion.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/vxge/vxge-config.c b/drivers/net/vxge/vxge-config.c
index 93b0462..683a6b7 100644
--- a/drivers/net/vxge/vxge-config.c
+++ b/drivers/net/vxge/vxge-config.c
@@ -1218,14 +1218,13 @@ __vxge_hw_ring_mempool_item_alloc(struct vxge_hw_mempool *mempoolh,
 }
 
 /*
- * __vxge_hw_ring_initial_replenish - Initial replenish of RxDs
+ * __vxge_hw_ring_replenish - Initial replenish of RxDs
  * This function replenishes the RxDs from reserve array to work array
  */
 enum vxge_hw_status
-vxge_hw_ring_replenish(struct __vxge_hw_ring *ring, u16 min_flag)
+vxge_hw_ring_replenish(struct __vxge_hw_ring *ring)
 {
 	void *rxd;
-	int i = 0;
 	struct __vxge_hw_channel *channel;
 	enum vxge_hw_status status = VXGE_HW_OK;
 
@@ -1246,11 +1245,6 @@ vxge_hw_ring_replenish(struct __vxge_hw_ring *ring, u16 min_flag)
 		}
 
 		vxge_hw_ring_rxd_post(ring, rxd);
-		if (min_flag) {
-			i++;
-			if (i == VXGE_HW_RING_MIN_BUFF_ALLOCATION)
-				break;
-		}
 	}
 	status = VXGE_HW_OK;
 exit:
@@ -1355,7 +1349,7 @@ __vxge_hw_ring_create(struct __vxge_hw_vpath_handle *vp,
 	 * Currently we don't have a case when the 1) is done without the 2).
 	 */
 	if (ring->rxd_init) {
-		status = vxge_hw_ring_replenish(ring, 1);
+		status = vxge_hw_ring_replenish(ring);
 		if (status != VXGE_HW_OK) {
 			__vxge_hw_ring_delete(vp);
 			goto exit;
@@ -1417,7 +1411,7 @@ enum vxge_hw_status __vxge_hw_ring_reset(struct __vxge_hw_ring *ring)
 		goto exit;
 
 	if (ring->rxd_init) {
-		status = vxge_hw_ring_replenish(ring, 1);
+		status = vxge_hw_ring_replenish(ring);
 		if (status != VXGE_HW_OK)
 			goto exit;
 	}
diff --git a/drivers/net/vxge/vxge-main.c b/drivers/net/vxge/vxge-main.c
index dd42c53..6c6c014 100644
--- a/drivers/net/vxge/vxge-main.c
+++ b/drivers/net/vxge/vxge-main.c
@@ -440,7 +440,7 @@ vxge_rx_1b_compl(struct __vxge_hw_ring *ringh, void *dtr,
 		ring->ndev->name, __func__, __LINE__);
 	ring->pkts_processed = 0;
 
-	vxge_hw_ring_replenish(ringh, 0);
+	vxge_hw_ring_replenish(ringh);
 
 	do {
 		prefetch((char *)dtr + L1_CACHE_BYTES);
diff --git a/drivers/net/vxge/vxge-traffic.h b/drivers/net/vxge/vxge-traffic.h
index 3c35e44..bed6528 100644
--- a/drivers/net/vxge/vxge-traffic.h
+++ b/drivers/net/vxge/vxge-traffic.h
@@ -1955,7 +1955,7 @@ vxge_hw_ring_rxd_post_post(
 	void *rxdh);
 
 enum vxge_hw_status
-vxge_hw_ring_replenish(struct __vxge_hw_ring *ring_handle, u16 min_flag);
+vxge_hw_ring_replenish(struct __vxge_hw_ring *ring_handle);
 
 void
 vxge_hw_ring_rxd_post_post_wmb(
@@ -2087,7 +2087,6 @@ void vxge_hw_fifo_txdl_free(
 
 #define VXGE_HW_RING_NEXT_BLOCK_POINTER_OFFSET	(VXGE_HW_BLOCK_SIZE-8)
 #define VXGE_HW_RING_MEMBLOCK_IDX_OFFSET		(VXGE_HW_BLOCK_SIZE-16)
-#define VXGE_HW_RING_MIN_BUFF_ALLOCATION		64
 
 /*
  * struct __vxge_hw_ring_rxd_priv - Receive descriptor HW-private data.