1 files changed, 170 insertions, 131 deletions

diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
index 31a434d2f143..63bf0119f949 100644
--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -53,14 +53,6 @@
 # define RPCDBG_FACILITY	RPCDBG_TRANS
 #endif
 
-enum rpcrdma_chunktype {
-	rpcrdma_noch = 0,
-	rpcrdma_readch,
-	rpcrdma_areadch,
-	rpcrdma_writech,
-	rpcrdma_replych
-};
-
 static const char transfertypes[][12] = {
 	"inline",	/* no chunks */
 	"read list",	/* some argument via rdma read */
@@ -157,42 +149,6 @@ static bool rpcrdma_results_inline(struct rpcrdma_xprt *r_xprt,
 	return rqst->rq_rcv_buf.buflen <= ia->ri_max_inline_read;
 }
 
-static int
-rpcrdma_tail_pullup(struct xdr_buf *buf)
-{
-	size_t tlen = buf->tail[0].iov_len;
-	size_t skip = tlen & 3;
-
-	/* Do not include the tail if it is only an XDR pad */
-	if (tlen < 4)
-		return 0;
-
-	/* xdr_write_pages() adds a pad at the beginning of the tail
-	 * if the content in "buf->pages" is unaligned. Force the
-	 * tail's actual content to land at the next XDR position
-	 * after the head instead.
-	 */
-	if (skip) {
-		unsigned char *src, *dst;
-		unsigned int count;
-
-		src = buf->tail[0].iov_base;
-		dst = buf->head[0].iov_base;
-		dst += buf->head[0].iov_len;
-
-		src += skip;
-		tlen -= skip;
-
-		dprintk("RPC:       %s: skip=%zu, memmove(%p, %p, %zu)\n",
-			__func__, skip, dst, src, tlen);
-
-		for (count = tlen; count; count--)
-			*dst++ = *src++;
-	}
-
-	return tlen;
-}
-
 /* Split "vec" on page boundaries into segments. FMR registers pages,
  * not a byte range. Other modes coalesce these segments into a single
  * MR when they can.
@@ -503,74 +459,184 @@ rpcrdma_encode_reply_chunk(struct rpcrdma_xprt *r_xprt,
 	return iptr;
 }
 
-/*
- * Copy write data inline.
- * This function is used for "small" requests. Data which is passed
- * to RPC via iovecs (or page list) is copied directly into the
- * pre-registered memory buffer for this request. For small amounts
- * of data, this is efficient. The cutoff value is tunable.
+/* Prepare the RPC-over-RDMA header SGE.
  */
-static void rpcrdma_inline_pullup(struct rpc_rqst *rqst)
+static bool
+rpcrdma_prepare_hdr_sge(struct rpcrdma_ia *ia, struct rpcrdma_req *req,
+			u32 len)
 {
-	int i, npages, curlen;
-	int copy_len;
-	unsigned char *srcp, *destp;
-	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_xprt);
-	int page_base;
-	struct page **ppages;
+	struct rpcrdma_regbuf *rb = req->rl_rdmabuf;
+	struct ib_sge *sge = &req->rl_send_sge[0];
+
+	if (unlikely(!rpcrdma_regbuf_is_mapped(rb))) {
+		if (!__rpcrdma_dma_map_regbuf(ia, rb))
+			return false;
+		sge->addr = rdmab_addr(rb);
+		sge->lkey = rdmab_lkey(rb);
+	}
+	sge->length = len;
 
-	destp = rqst->rq_svec[0].iov_base;
-	curlen = rqst->rq_svec[0].iov_len;
-	destp += curlen;
+	ib_dma_sync_single_for_device(ia->ri_device, sge->addr,
+				      sge->length, DMA_TO_DEVICE);
+	req->rl_send_wr.num_sge++;
+	return true;
+}
 
-	dprintk("RPC:       %s: destp 0x%p len %d hdrlen %d\n",
-		__func__, destp, rqst->rq_slen, curlen);
+/* Prepare the Send SGEs. The head and tail iovec, and each entry
+ * in the page list, gets its own SGE.
+ */
+static bool
+rpcrdma_prepare_msg_sges(struct rpcrdma_ia *ia, struct rpcrdma_req *req,
+			 struct xdr_buf *xdr, enum rpcrdma_chunktype rtype)
+{
+	unsigned int sge_no, page_base, len, remaining;
+	struct rpcrdma_regbuf *rb = req->rl_sendbuf;
+	struct ib_device *device = ia->ri_device;
+	struct ib_sge *sge = req->rl_send_sge;
+	u32 lkey = ia->ri_pd->local_dma_lkey;
+	struct page *page, **ppages;
+
+	/* The head iovec is straightforward, as it is already
+	 * DMA-mapped. Sync the content that has changed.
+	 */
+	if (!rpcrdma_dma_map_regbuf(ia, rb))
+		return false;
+	sge_no = 1;
+	sge[sge_no].addr = rdmab_addr(rb);
+	sge[sge_no].length = xdr->head[0].iov_len;
+	sge[sge_no].lkey = rdmab_lkey(rb);
+	ib_dma_sync_single_for_device(device, sge[sge_no].addr,
+				      sge[sge_no].length, DMA_TO_DEVICE);
+
+	/* If there is a Read chunk, the page list is being handled
+	 * via explicit RDMA, and thus is skipped here. However, the
+	 * tail iovec may include an XDR pad for the page list, as
+	 * well as additional content, and may not reside in the
+	 * same page as the head iovec.
+	 */
+	if (rtype == rpcrdma_readch) {
+		len = xdr->tail[0].iov_len;
 
-	copy_len = rqst->rq_snd_buf.page_len;
+		/* Do not include the tail if it is only an XDR pad */
+		if (len < 4)
+			goto out;
 
-	if (rqst->rq_snd_buf.tail[0].iov_len) {
-		curlen = rqst->rq_snd_buf.tail[0].iov_len;
-		if (destp + copy_len != rqst->rq_snd_buf.tail[0].iov_base) {
-			memmove(destp + copy_len,
-				rqst->rq_snd_buf.tail[0].iov_base, curlen);
-			r_xprt->rx_stats.pullup_copy_count += curlen;
+		page = virt_to_page(xdr->tail[0].iov_base);
+		page_base = (unsigned long)xdr->tail[0].iov_base & ~PAGE_MASK;
+
+		/* If the content in the page list is an odd length,
+		 * xdr_write_pages() has added a pad at the beginning
+		 * of the tail iovec. Force the tail's non-pad content
+		 * to land at the next XDR position in the Send message.
+		 */
+		page_base += len & 3;
+		len -= len & 3;
+		goto map_tail;
+	}
+
+	/* If there is a page list present, temporarily DMA map
+	 * and prepare an SGE for each page to be sent.
+	 */
+	if (xdr->page_len) {
+		ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT);
+		page_base = xdr->page_base & ~PAGE_MASK;
+		remaining = xdr->page_len;
+		while (remaining) {
+			sge_no++;
+			if (sge_no > RPCRDMA_MAX_SEND_SGES - 2)
+				goto out_mapping_overflow;
+
+			len = min_t(u32, PAGE_SIZE - page_base, remaining);
+			sge[sge_no].addr = ib_dma_map_page(device, *ppages,
+							   page_base, len,
+							   DMA_TO_DEVICE);
+			if (ib_dma_mapping_error(device, sge[sge_no].addr))
+				goto out_mapping_err;
+			sge[sge_no].length = len;
+			sge[sge_no].lkey = lkey;
+
+			req->rl_mapped_sges++;
+			ppages++;
+			remaining -= len;
+			page_base = 0;
 		}
-		dprintk("RPC:       %s: tail destp 0x%p len %d\n",
-			__func__, destp + copy_len, curlen);
-		rqst->rq_svec[0].iov_len += curlen;
 	}
-	r_xprt->rx_stats.pullup_copy_count += copy_len;
 
-	page_base = rqst->rq_snd_buf.page_base;
-	ppages = rqst->rq_snd_buf.pages + (page_base >> PAGE_SHIFT);
-	page_base &= ~PAGE_MASK;
-	npages = PAGE_ALIGN(page_base+copy_len) >> PAGE_SHIFT;
-	for (i = 0; copy_len && i < npages; i++) {
-		curlen = PAGE_SIZE - page_base;
-		if (curlen > copy_len)
-			curlen = copy_len;
-		dprintk("RPC:       %s: page %d destp 0x%p len %d curlen %d\n",
-			__func__, i, destp, copy_len, curlen);
-		srcp = kmap_atomic(ppages[i]);
-		memcpy(destp, srcp+page_base, curlen);
-		kunmap_atomic(srcp);
-		rqst->rq_svec[0].iov_len += curlen;
-		destp += curlen;
-		copy_len -= curlen;
-		page_base = 0;
+	/* The tail iovec is not always constructed in the same
+	 * page where the head iovec resides (see, for example,
+	 * gss_wrap_req_priv). To neatly accommodate that case,
+	 * DMA map it separately.
+	 */
+	if (xdr->tail[0].iov_len) {
+		page = virt_to_page(xdr->tail[0].iov_base);
+		page_base = (unsigned long)xdr->tail[0].iov_base & ~PAGE_MASK;
+		len = xdr->tail[0].iov_len;
+
+map_tail:
+		sge_no++;
+		sge[sge_no].addr = ib_dma_map_page(device, page,
+						   page_base, len,
+						   DMA_TO_DEVICE);
+		if (ib_dma_mapping_error(device, sge[sge_no].addr))
+			goto out_mapping_err;
+		sge[sge_no].length = len;
+		sge[sge_no].lkey = lkey;
+		req->rl_mapped_sges++;
 	}
-	/* header now contains entire send message */
+
+out:
+	req->rl_send_wr.num_sge = sge_no + 1;
+	return true;
+
+out_mapping_overflow:
+	pr_err("rpcrdma: too many Send SGEs (%u)\n", sge_no);
+	return false;
+
+out_mapping_err:
+	pr_err("rpcrdma: Send mapping error\n");
+	return false;
+}
+
+bool
+rpcrdma_prepare_send_sges(struct rpcrdma_ia *ia, struct rpcrdma_req *req,
+			  u32 hdrlen, struct xdr_buf *xdr,
+			  enum rpcrdma_chunktype rtype)
+{
+	req->rl_send_wr.num_sge = 0;
+	req->rl_mapped_sges = 0;
+
+	if (!rpcrdma_prepare_hdr_sge(ia, req, hdrlen))
+		goto out_map;
+
+	if (rtype != rpcrdma_areadch)
+		if (!rpcrdma_prepare_msg_sges(ia, req, xdr, rtype))
+			goto out_map;
+
+	return true;
+
+out_map:
+	pr_err("rpcrdma: failed to DMA map a Send buffer\n");
+	return false;
+}
+
+void
+rpcrdma_unmap_sges(struct rpcrdma_ia *ia, struct rpcrdma_req *req)
+{
+	struct ib_device *device = ia->ri_device;
+	struct ib_sge *sge;
+	int count;
+
+	sge = &req->rl_send_sge[2];
+	for (count = req->rl_mapped_sges; count--; sge++)
+		ib_dma_unmap_page(device, sge->addr, sge->length,
+				  DMA_TO_DEVICE);
+	req->rl_mapped_sges = 0;
 }
 
 /*
  * Marshal a request: the primary job of this routine is to choose
  * the transfer modes. See comments below.
  *
- * Prepares up to two IOVs per Call message:
- *
- *  [0] -- RPC RDMA header
- *  [1] -- the RPC header/data
- *
  * Returns zero on success, otherwise a negative errno.
  */
 
@@ -638,12 +704,11 @@ rpcrdma_marshal_req(struct rpc_rqst *rqst)
 	 */
 	if (rpcrdma_args_inline(r_xprt, rqst)) {
 		rtype = rpcrdma_noch;
-		rpcrdma_inline_pullup(rqst);
-		rpclen = rqst->rq_svec[0].iov_len;
+		rpclen = rqst->rq_snd_buf.len;
 	} else if (ddp_allowed && rqst->rq_snd_buf.flags & XDRBUF_WRITE) {
 		rtype = rpcrdma_readch;
-		rpclen = rqst->rq_svec[0].iov_len;
-		rpclen += rpcrdma_tail_pullup(&rqst->rq_snd_buf);
+		rpclen = rqst->rq_snd_buf.head[0].iov_len +
+			 rqst->rq_snd_buf.tail[0].iov_len;
 	} else {
 		r_xprt->rx_stats.nomsg_call_count++;
 		headerp->rm_type = htonl(RDMA_NOMSG);
@@ -685,47 +750,21 @@ rpcrdma_marshal_req(struct rpc_rqst *rqst)
 		goto out_unmap;
 	hdrlen = (unsigned char *)iptr - (unsigned char *)headerp;
 
-	if (hdrlen + rpclen > r_xprt->rx_data.inline_wsize)
-		goto out_overflow;
-
 	dprintk("RPC: %5u %s: %s/%s: hdrlen %zd rpclen %zd\n",
 		rqst->rq_task->tk_pid, __func__,
 		transfertypes[rtype], transfertypes[wtype],
 		hdrlen, rpclen);
 
-	if (!rpcrdma_dma_map_regbuf(&r_xprt->rx_ia, req->rl_rdmabuf))
-		goto out_map;
-	req->rl_send_iov[0].addr = rdmab_addr(req->rl_rdmabuf);
-	req->rl_send_iov[0].length = hdrlen;
-	req->rl_send_iov[0].lkey = rdmab_lkey(req->rl_rdmabuf);
-
-	req->rl_send_wr.num_sge = 1;
-	if (rtype == rpcrdma_areadch)
-		return 0;
-
-	if (!rpcrdma_dma_map_regbuf(&r_xprt->rx_ia, req->rl_sendbuf))
-		goto out_map;
-	req->rl_send_iov[1].addr = rdmab_addr(req->rl_sendbuf);
-	req->rl_send_iov[1].length = rpclen;
-	req->rl_send_iov[1].lkey = rdmab_lkey(req->rl_sendbuf);
-
-	req->rl_send_wr.num_sge = 2;
-
+	if (!rpcrdma_prepare_send_sges(&r_xprt->rx_ia, req, hdrlen,
+				       &rqst->rq_snd_buf, rtype)) {
+		iptr = ERR_PTR(-EIO);
+		goto out_unmap;
+	}
 	return 0;
 
-out_overflow:
-	pr_err("rpcrdma: send overflow: hdrlen %zd rpclen %zu %s/%s\n",
-		hdrlen, rpclen, transfertypes[rtype], transfertypes[wtype]);
-	iptr = ERR_PTR(-EIO);
-
 out_unmap:
 	r_xprt->rx_ia.ri_ops->ro_unmap_safe(r_xprt, req, false);
 	return PTR_ERR(iptr);
-
-out_map:
-	pr_err("rpcrdma: failed to DMA map a Send buffer\n");
-	iptr = ERR_PTR(-EIO);
-	goto out_unmap;
 }
 
 /*