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authorSteve Wise <swise@opengridcomputing.com>2015-09-28 16:46:06 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-10-27 09:51:59 +0900
commit23a0f8cd351ed6908c24273a174c8c2bd807134f (patch)
treec60eb1599146687723f98555f4578c9ea3c386a2 /net
parentae7d500538b57f329614db03ed2e46d1e54d8192 (diff)
svcrdma: handle rdma read with a non-zero initial page offset
commit c91aed9896946721bb30705ea2904edb3725dd61 upstream. The server rdma_read_chunk_lcl() and rdma_read_chunk_frmr() functions were not taking into account the initial page_offset when determining the rdma read length. This resulted in a read who's starting address and length exceeded the base/bounds of the frmr. The server gets an async error from the rdma device and kills the connection, and the client then reconnects and resends. This repeats indefinitely, and the application hangs. Most work loads don't tickle this bug apparently, but one test hit it every time: building the linux kernel on a 16 core node with 'make -j 16 O=/mnt/0' where /mnt/0 is a ramdisk mounted via NFSRDMA. This bug seems to only be tripped with devices having small fastreg page list depths. I didn't see it with mlx4, for instance. Fixes: 0bf4828983df ('svcrdma: refactor marshalling logic') Signed-off-by: Steve Wise <swise@opengridcomputing.com> Tested-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
-rw-r--r--net/sunrpc/xprtrdma/svc_rdma_recvfrom.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index f9f13a32ddb8..2873b8d65608 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -146,7 +146,8 @@ int rdma_read_chunk_lcl(struct svcxprt_rdma *xprt,
ctxt->read_hdr = head;
pages_needed =
min_t(int, pages_needed, rdma_read_max_sge(xprt, pages_needed));
- read = min_t(int, pages_needed << PAGE_SHIFT, rs_length);
+ read = min_t(int, (pages_needed << PAGE_SHIFT) - *page_offset,
+ rs_length);
for (pno = 0; pno < pages_needed; pno++) {
int len = min_t(int, rs_length, PAGE_SIZE - pg_off);
@@ -245,7 +246,8 @@ int rdma_read_chunk_frmr(struct svcxprt_rdma *xprt,
ctxt->direction = DMA_FROM_DEVICE;
ctxt->frmr = frmr;
pages_needed = min_t(int, pages_needed, xprt->sc_frmr_pg_list_len);
- read = min_t(int, pages_needed << PAGE_SHIFT, rs_length);
+ read = min_t(int, (pages_needed << PAGE_SHIFT) - *page_offset,
+ rs_length);
frmr->kva = page_address(rqstp->rq_arg.pages[pg_no]);
frmr->direction = DMA_FROM_DEVICE;