c8237a5fce
The RDMACTXT_F_LAST_CTXT bit was getting set incorrectly when the last chunk in the read-list spanned multiple pages. This resulted in a kernel panic when the wrong context was used to build the RPC iovec page list. RDMA_READ is used to fetch RPC data from the client for NFS_WRITE requests. A scatter-gather is used to map the advertised client side buffer to the server-side iovec and associated page list. WR contexts are used to convey which scatter-gather entries are handled by each WR. When the write data is large, a single RPC may require multiple RDMA_READ requests so the contexts for a single RPC are chained together in a linked list. The last context in this list is marked with a bit RDMACTXT_F_LAST_CTXT so that when this WR completes, the CQ handler code can enqueue the RPC for processing. The code in rdma_read_xdr was setting this bit on the last two contexts on this list when the last read-list chunk spanned multiple pages. This caused the svc_rdma_recvfrom logic to incorrectly build the RPC and caused the kernel to crash because the second-to-last context doesn't contain the iovec page list. Modified the condition that sets this bit so that it correctly detects the last context for the RPC. Signed-off-by: Tom Tucker <tom@opengridcomputing.com> Tested-by: Roland Dreier <rolandd@cisco.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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| .. | ||
| Makefile | ||
| rpc_rdma.c | ||
| svc_rdma_marshal.c | ||
| svc_rdma_recvfrom.c | ||
| svc_rdma_sendto.c | ||
| svc_rdma_transport.c | ||
| svc_rdma.c | ||
| transport.c | ||
| verbs.c | ||
| xprt_rdma.h | ||