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authorRoland Dreier <rdreier@cisco.com>2008-03-24 12:03:03 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-03-24 11:25:25 -0700
commitd3073779f8362d64b804882f5f41c208c4a5e11e (patch)
tree6aa6a950cc9bed39deafd73bca1e99e108d31b51 /net
parentb9e76a00749521f2b080fa8a4fb15f66538ab756 (diff)
SVCRDMA: Use only 1 RDMA read scatter entry for iWARP adapters
The iWARP protocol limits RDMA read requests to a single scatter entry. NFS/RDMA has code in rdma_read_max_sge() that is supposed to limit the sge_count for RDMA read requests to 1, but the code to do that is inside an #ifdef RDMA_TRANSPORT_IWARP block. In the mainline kernel at least, RDMA_TRANSPORT_IWARP is an enum and not a preprocessor #define, so the #ifdef'ed code is never compiled. In my test of a kernel build with -j8 on an NFS/RDMA mount, this problem eventually leads to trouble starting with: svcrdma: Error posting send = -22 svcrdma : RDMA_READ error = -22 and things go downhill from there. The trivial fix is to delete the #ifdef guard. The check seems to be a remnant of when the NFS/RDMA code was not merged and needed to compile against multiple kernel versions, although I don't think it ever worked as intended. In any case now that the code is upstream there's no need to test whether the RDMA_TRANSPORT_IWARP constant is defined or not. Without this patch, my kernel build on an NFS/RDMA mount using NetEffect adapters quickly and 100% reproducibly failed with an error like: ld: final link failed: Software caused connection abort With the patch applied I was able to complete a kernel build on the same setup. (Tom Tucker says this is "actually an _ancient_ remnant when it had to compile against iWARP vs. non-iWARP enabled OFA trees.") Signed-off-by: Roland Dreier <rolandd@cisco.com> Acked-by: Tom Tucker <tom@opengridcomputing.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'net')
-rw-r--r--net/sunrpc/xprtrdma/svc_rdma_recvfrom.c2
1 files changed, 0 insertions, 2 deletions
diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index ab54a736486..971271602dd 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -237,14 +237,12 @@ static void rdma_set_ctxt_sge(struct svc_rdma_op_ctxt *ctxt,
static int rdma_read_max_sge(struct svcxprt_rdma *xprt, int sge_count)
{
-#ifdef RDMA_TRANSPORT_IWARP
if ((RDMA_TRANSPORT_IWARP ==
rdma_node_get_transport(xprt->sc_cm_id->
device->node_type))
&& sge_count > 1)
return 1;
else
-#endif
return min_t(int, sge_count, xprt->sc_max_sge);
}