See RFC 5666 section 3.7: clients don't have to send zero XDR padding. BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=246 Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx> --- net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 28 ++++++++++++++++++++++++++++ 1 files changed, 28 insertions(+), 0 deletions(-) diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c index 8f92a61..3a45bf4 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c @@ -43,6 +43,7 @@ #include <linux/sunrpc/debug.h> #include <linux/sunrpc/rpc_rdma.h> #include <linux/spinlock.h> +#include <linux/highmem.h> #include <asm/unaligned.h> #include <rdma/ib_verbs.h> #include <rdma/rdma_cm.h> @@ -435,6 +436,32 @@ static int rdma_read_chunks(struct svcxprt_rdma *xprt, return ret; } +/* + * To avoid a separate RDMA READ just for a handful of zero bytes, + * RFC 5666 section 3.7 allows the client to omit the XDR zero pad + * in chunk lists. + */ +static void +rdma_fix_xdr_pad(struct xdr_buf *buf) +{ + unsigned int page_len = buf->page_len; + unsigned int size = (XDR_QUADLEN(page_len) << 2) - page_len; + unsigned int offset, pg_no; + char *p; + + if (size == 0) + return; + + pg_no = page_len >> PAGE_SHIFT; + offset = page_len & ~PAGE_MASK; + p = page_address(buf->pages[pg_no]); + memset(p + offset, 0, size); + + buf->page_len += size; + buf->buflen += size; + buf->len += size; +} + static int rdma_read_complete(struct svc_rqst *rqstp, struct svc_rdma_op_ctxt *head) { @@ -449,6 +476,7 @@ static int rdma_read_complete(struct svc_rqst *rqstp, rqstp->rq_pages[page_no] = head->pages[page_no]; } /* Point rq_arg.pages past header */ + rdma_fix_xdr_pad(&head->arg); rqstp->rq_arg.pages = &rqstp->rq_pages[head->hdr_count]; rqstp->rq_arg.page_len = head->arg.page_len; rqstp->rq_arg.page_base = head->arg.page_base; -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
