Refactor: Replace spaghetti with code that makes it plain what needs
to be done for each rtype. This makes it easier to add features and
optimizations.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
net/sunrpc/xprtrdma/rpc_rdma.c | 263 ++++++++++++++++++++++------------------
1 file changed, 146 insertions(+), 117 deletions(-)
diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
index 53cd2e3..a441dbf 100644
--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -589,148 +589,162 @@ static bool rpcrdma_prepare_hdr_sge(struct rpcrdma_xprt *r_xprt,
{
struct rpcrdma_sendctx *sc = req->rl_sendctx;
struct rpcrdma_regbuf *rb = req->rl_rdmabuf;
- struct ib_sge *sge = sc->sc_sges;
+ struct ib_sge *sge = &sc->sc_sges[req->rl_wr.num_sge++];
if (!rpcrdma_regbuf_dma_map(r_xprt, rb))
- goto out_regbuf;
+ return false;
sge->addr = rdmab_addr(rb);
sge->length = len;
sge->lkey = rdmab_lkey(rb);
ib_dma_sync_single_for_device(rdmab_device(rb), sge->addr, sge->length,
DMA_TO_DEVICE);
- req->rl_wr.num_sge++;
return true;
-
-out_regbuf:
- pr_err("rpcrdma: failed to DMA map a Send buffer\n");
- return false;
}
-/* Prepare the Send SGEs. The head and tail iovec, and each entry
- * in the page list, gets its own SGE.
+/* The head iovec is straightforward, as it is usually already
+ * DMA-mapped. Sync the content that has changed.
*/
-static bool rpcrdma_prepare_msg_sges(struct rpcrdma_xprt *r_xprt,
- struct rpcrdma_req *req,
- struct xdr_buf *xdr,
- enum rpcrdma_chunktype rtype)
+static bool rpcrdma_prepare_head_iov(struct rpcrdma_xprt *r_xprt,
+ struct rpcrdma_req *req, unsigned int len)
{
struct rpcrdma_sendctx *sc = req->rl_sendctx;
- unsigned int sge_no, page_base, len, remaining;
+ struct ib_sge *sge = &sc->sc_sges[req->rl_wr.num_sge++];
struct rpcrdma_regbuf *rb = req->rl_sendbuf;
- struct ib_sge *sge = sc->sc_sges;
- struct page *page, **ppages;
- /* The head iovec is straightforward, as it is already
- * DMA-mapped. Sync the content that has changed.
- */
if (!rpcrdma_regbuf_dma_map(r_xprt, rb))
- goto out_regbuf;
- 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(rdmab_device(rb), 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;
+ return false;
- /* Do not include the tail if it is only an XDR pad */
- if (len < 4)
- goto out;
+ sge->addr = rdmab_addr(rb);
+ sge->length = len;
+ sge->lkey = rdmab_lkey(rb);
- page = virt_to_page(xdr->tail[0].iov_base);
- page_base = offset_in_page(xdr->tail[0].iov_base);
+ ib_dma_sync_single_for_device(rdmab_device(rb), sge->addr, sge->length,
+ DMA_TO_DEVICE);
+ return true;
+}
- /* 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, DMA map and prepare an
+ * SGE for each page to be sent.
+ */
+static bool rpcrdma_prepare_pagelist(struct rpcrdma_req *req,
+ struct xdr_buf *xdr)
+{
+ struct rpcrdma_sendctx *sc = req->rl_sendctx;
+ struct rpcrdma_regbuf *rb = req->rl_sendbuf;
+ unsigned int page_base, len, remaining;
+ struct page **ppages;
+ struct ib_sge *sge;
- /* 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 = offset_in_page(xdr->page_base);
- 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(rdmab_device(rb), *ppages,
- page_base, len, DMA_TO_DEVICE);
- if (ib_dma_mapping_error(rdmab_device(rb),
- sge[sge_no].addr))
- goto out_mapping_err;
- sge[sge_no].length = len;
- sge[sge_no].lkey = rdmab_lkey(rb);
-
- sc->sc_unmap_count++;
- ppages++;
- remaining -= len;
- page_base = 0;
- }
- }
+ ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT);
+ page_base = offset_in_page(xdr->page_base);
+ remaining = xdr->page_len;
+ while (remaining) {
+ sge = &sc->sc_sges[req->rl_wr.num_sge++];
+ len = min_t(unsigned int, PAGE_SIZE - page_base, remaining);
+ sge->addr = ib_dma_map_page(rdmab_device(rb), *ppages,
+ page_base, len, DMA_TO_DEVICE);
+ if (ib_dma_mapping_error(rdmab_device(rb), sge->addr))
+ goto out_mapping_err;
- /* 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 = offset_in_page(xdr->tail[0].iov_base);
- len = xdr->tail[0].iov_len;
+ sge->length = len;
+ sge->lkey = rdmab_lkey(rb);
-map_tail:
- sge_no++;
- sge[sge_no].addr =
- ib_dma_map_page(rdmab_device(rb), page, page_base, len,
- DMA_TO_DEVICE);
- if (ib_dma_mapping_error(rdmab_device(rb), sge[sge_no].addr))
- goto out_mapping_err;
- sge[sge_no].length = len;
- sge[sge_no].lkey = rdmab_lkey(rb);
sc->sc_unmap_count++;
+ ppages++;
+ remaining -= len;
+ page_base = 0;
}
-out:
- req->rl_wr.num_sge += sge_no;
- if (sc->sc_unmap_count)
- kref_get(&req->rl_kref);
return true;
-out_regbuf:
- pr_err("rpcrdma: failed to DMA map a Send buffer\n");
+out_mapping_err:
+ trace_xprtrdma_dma_maperr(sge->addr);
return false;
+}
-out_mapping_overflow:
- rpcrdma_sendctx_unmap(sc);
- pr_err("rpcrdma: too many Send SGEs (%u)\n", sge_no);
- return false;
+/* 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.
+ */
+static bool rpcrdma_prepare_tail_iov(struct rpcrdma_req *req,
+ struct xdr_buf *xdr,
+ unsigned int page_base, unsigned int len)
+{
+ struct rpcrdma_sendctx *sc = req->rl_sendctx;
+ struct ib_sge *sge = &sc->sc_sges[req->rl_wr.num_sge++];
+ struct rpcrdma_regbuf *rb = req->rl_sendbuf;
+ struct page *page = virt_to_page(xdr->tail[0].iov_base);
+
+ sge->addr = ib_dma_map_page(rdmab_device(rb), page, page_base, len,
+ DMA_TO_DEVICE);
+ if (ib_dma_mapping_error(rdmab_device(rb), sge->addr))
+ goto out_mapping_err;
+
+ sge->length = len;
+ sge->lkey = rdmab_lkey(rb);
+ ++sc->sc_unmap_count;
+ return true;
out_mapping_err:
- rpcrdma_sendctx_unmap(sc);
- trace_xprtrdma_dma_maperr(sge[sge_no].addr);
+ trace_xprtrdma_dma_maperr(sge->addr);
return false;
}
+static bool rpcrdma_prepare_noch_mapped(struct rpcrdma_xprt *r_xprt,
+ struct rpcrdma_req *req,
+ struct xdr_buf *xdr)
+{
+ struct kvec *tail = &xdr->tail[0];
+
+ if (!rpcrdma_prepare_head_iov(r_xprt, req, xdr->head[0].iov_len))
+ return false;
+ if (xdr->page_len)
+ if (!rpcrdma_prepare_pagelist(req, xdr))
+ return false;
+ if (tail->iov_len)
+ if (!rpcrdma_prepare_tail_iov(req, xdr,
+ offset_in_page(tail->iov_base),
+ tail->iov_len))
+ return false;
+
+ if (req->rl_sendctx->sc_unmap_count)
+ kref_get(&req->rl_kref);
+ return true;
+}
+
+static bool rpcrdma_prepare_readch(struct rpcrdma_xprt *r_xprt,
+ struct rpcrdma_req *req,
+ struct xdr_buf *xdr)
+{
+ if (!rpcrdma_prepare_head_iov(r_xprt, req, xdr->head[0].iov_len))
+ return false;
+
+ /* If there is a Read chunk, the page list is being handled
+ * via explicit RDMA, and thus is skipped here.
+ */
+
+ /* Do not include the tail if it is only an XDR pad */
+ if (xdr->tail[0].iov_len > 3) {
+ unsigned int page_base, len;
+
+ /* If the content in the page list is an odd length,
+ * xdr_write_pages() adds 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 = offset_in_page(xdr->tail[0].iov_base);
+ len = xdr->tail[0].iov_len;
+ page_base += len & 3;
+ len -= len & 3;
+ if (!rpcrdma_prepare_tail_iov(req, xdr, page_base, len))
+ return false;
+ kref_get(&req->rl_kref);
+ }
+
+ return true;
+}
+
/**
* rpcrdma_prepare_send_sges - Construct SGEs for a Send WR
* @r_xprt: controlling transport
@@ -741,17 +755,17 @@ static bool rpcrdma_prepare_msg_sges(struct rpcrdma_xprt *r_xprt,
*
* Returns 0 on success; otherwise a negative errno is returned.
*/
-int
-rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt,
- struct rpcrdma_req *req, u32 hdrlen,
- struct xdr_buf *xdr, enum rpcrdma_chunktype rtype)
+inline int rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt,
+ struct rpcrdma_req *req, u32 hdrlen,
+ struct xdr_buf *xdr,
+ enum rpcrdma_chunktype rtype)
{
int ret;
ret = -EAGAIN;
req->rl_sendctx = rpcrdma_sendctx_get_locked(r_xprt);
if (!req->rl_sendctx)
- goto err;
+ goto out_nosc;
req->rl_sendctx->sc_unmap_count = 0;
req->rl_sendctx->sc_req = req;
kref_init(&req->rl_kref);
@@ -762,13 +776,28 @@ static bool rpcrdma_prepare_msg_sges(struct rpcrdma_xprt *r_xprt,
ret = -EIO;
if (!rpcrdma_prepare_hdr_sge(r_xprt, req, hdrlen))
- goto err;
- if (rtype != rpcrdma_areadch)
- if (!rpcrdma_prepare_msg_sges(r_xprt, req, xdr, rtype))
- goto err;
+ goto out_unmap;
+
+ switch (rtype) {
+ case rpcrdma_noch:
+ if (!rpcrdma_prepare_noch_mapped(r_xprt, req, xdr))
+ goto out_unmap;
+ break;
+ case rpcrdma_readch:
+ if (!rpcrdma_prepare_readch(r_xprt, req, xdr))
+ goto out_unmap;
+ break;
+ case rpcrdma_areadch:
+ break;
+ default:
+ goto out_unmap;
+ }
+
return 0;
-err:
+out_unmap:
+ rpcrdma_sendctx_unmap(req->rl_sendctx);
+out_nosc:
trace_xprtrdma_prepsend_failed(&req->rl_slot, ret);
return ret;
}
