From: Amir Vadai <amirv@mellanox.co.il>
Date: Tue, 28 Apr 2009 06:40:10 +0000 (+0300)
Subject: sdp: BUG1311 Netpipe fails with a IB_WC_LOC_LEN_ERR.
X-Git-Tag: v4.1.12-92~264^2~5^2~291
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=23902318d166592a98d5c82959cac76965097abb;p=users%2Fjedix%2Flinux-maple.git

sdp: BUG1311 Netpipe fails with a IB_WC_LOC_LEN_ERR.

This problem is seen when the receive buffer or the receive buffer fragments
are smaller than the senders buffer. If the sender is using 64KB pages
and supports a sk fragment of 64KB it may send fragments that are a full 64KB
in length causing the receiver to generate an IB_WC_LOC_LEN_ERR. This patch
makes two changes:

If the kernel does not support a full 64KB fragment it will reject resize
requests over 32K. (On older kernels a fragment size is defined as a U16)

If a kernel supports a 64KB fragment then it allows a full 64KB receive
fragment to be used.

Signed-off-by: David Wilder <dwilder@us.ibm.com>
Signed-off-by: Amir Vadai <amirv@mellanox.co.il>
---

diff --git a/drivers/infiniband/ulp/sdp/sdp_bcopy.c b/drivers/infiniband/ulp/sdp/sdp_bcopy.c
index 1288c68e632dc..475d7c3629915 100644
--- a/drivers/infiniband/ulp/sdp/sdp_bcopy.c
+++ b/drivers/infiniband/ulp/sdp/sdp_bcopy.c
@@ -330,7 +330,13 @@ static void sdp_post_recv(struct sdp_sock *ssk)
 		frag = &skb_shinfo(skb)->frags[i];
 		frag->page                = page;
 		frag->page_offset         = 0;
-		frag->size                =  min(PAGE_SIZE, SDP_MAX_PAYLOAD);
+
+		/* Bugzilla 1311 */
+		if ( sizeof(frag->size) < 4 )
+			frag->size = min(PAGE_SIZE, SDP_MAX_PAYLOAD);
+		else
+			frag->size = PAGE_SIZE;
+
 		++skb_shinfo(skb)->nr_frags;
 		skb->len += frag->size;
 		skb->data_len += frag->size;
@@ -607,17 +613,16 @@ int sdp_init_buffers(struct sdp_sock *ssk, u32 new_size)
 
 int sdp_resize_buffers(struct sdp_sock *ssk, u32 new_size)
 {
+	skb_frag_t skb_frag;
 	u32 curr_size = SDP_HEAD_SIZE + ssk->recv_frags * PAGE_SIZE;
-#if defined(__ia64__)
-	/* for huge PAGE_SIZE systems, aka IA64, limit buffers size
-	   [re-]negotiation to a known+working size that will not
-	   trigger a HW error/rc to be interpreted as a IB_WC_LOC_LEN_ERR */
-	u32 max_size = (SDP_HEAD_SIZE + SDP_MAX_SEND_SKB_FRAGS * PAGE_SIZE) <=
-		32784 ?
-		(SDP_HEAD_SIZE + SDP_MAX_SEND_SKB_FRAGS * PAGE_SIZE): 32784;
-#else 
 	u32 max_size = SDP_HEAD_SIZE + SDP_MAX_SEND_SKB_FRAGS * PAGE_SIZE;
-#endif
+
+	/* Bugzilla 1311, Kernels using smaller fragments must reject
+	 * re-size requests larger than 32k to prevent being sent
+	 * fragment larger than the receive buffer fragment.
+	 */
+	if ( (sizeof(skb_frag.size) < 4) && (max_size > 0x8000))
+		max_size = 0x8000;
 
 	if (new_size > curr_size && new_size <= max_size &&
 	    sdp_get_large_socket(ssk)) {