svcrdma: Modify the RPC reply path to use FRMR when available
Use FRMR to map local RPC reply data. This allows RDMA_WRITE to send reply
data using a single WR. The FRMR is invalidated by linking the LOCAL_INV WR
to the RDMA_SEND message used to complete the reply.
Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
index 84d3283..9a7a8e7 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
@@ -69,9 +69,127 @@
* array is only concerned with the reply we are assured that we have
* on extra page for the RPCRMDA header.
*/
-static void xdr_to_sge(struct svcxprt_rdma *xprt,
- struct xdr_buf *xdr,
- struct svc_rdma_req_map *vec)
+int fast_reg_xdr(struct svcxprt_rdma *xprt,
+ struct xdr_buf *xdr,
+ struct svc_rdma_req_map *vec)
+{
+ int sge_no;
+ u32 sge_bytes;
+ u32 page_bytes;
+ u32 page_off;
+ int page_no = 0;
+ u8 *frva;
+ struct svc_rdma_fastreg_mr *frmr;
+
+ frmr = svc_rdma_get_frmr(xprt);
+ if (IS_ERR(frmr))
+ return -ENOMEM;
+ vec->frmr = frmr;
+
+ /* Skip the RPCRDMA header */
+ sge_no = 1;
+
+ /* Map the head. */
+ frva = (void *)((unsigned long)(xdr->head[0].iov_base) & PAGE_MASK);
+ vec->sge[sge_no].iov_base = xdr->head[0].iov_base;
+ vec->sge[sge_no].iov_len = xdr->head[0].iov_len;
+ vec->count = 2;
+ sge_no++;
+
+ /* Build the FRMR */
+ frmr->kva = frva;
+ frmr->direction = DMA_TO_DEVICE;
+ frmr->access_flags = 0;
+ frmr->map_len = PAGE_SIZE;
+ frmr->page_list_len = 1;
+ frmr->page_list->page_list[page_no] =
+ ib_dma_map_single(xprt->sc_cm_id->device,
+ (void *)xdr->head[0].iov_base,
+ PAGE_SIZE, DMA_TO_DEVICE);
+ if (ib_dma_mapping_error(xprt->sc_cm_id->device,
+ frmr->page_list->page_list[page_no]))
+ goto fatal_err;
+ atomic_inc(&xprt->sc_dma_used);
+
+ page_off = xdr->page_base;
+ page_bytes = xdr->page_len + page_off;
+ if (!page_bytes)
+ goto encode_tail;
+
+ /* Map the pages */
+ vec->sge[sge_no].iov_base = frva + frmr->map_len + page_off;
+ vec->sge[sge_no].iov_len = page_bytes;
+ sge_no++;
+ while (page_bytes) {
+ struct page *page;
+
+ page = xdr->pages[page_no++];
+ sge_bytes = min_t(u32, page_bytes, (PAGE_SIZE - page_off));
+ page_bytes -= sge_bytes;
+
+ frmr->page_list->page_list[page_no] =
+ ib_dma_map_page(xprt->sc_cm_id->device, page, 0,
+ PAGE_SIZE, DMA_TO_DEVICE);
+ if (ib_dma_mapping_error(xprt->sc_cm_id->device,
+ frmr->page_list->page_list[page_no]))
+ goto fatal_err;
+
+ atomic_inc(&xprt->sc_dma_used);
+ page_off = 0; /* reset for next time through loop */
+ frmr->map_len += PAGE_SIZE;
+ frmr->page_list_len++;
+ }
+ vec->count++;
+
+ encode_tail:
+ /* Map tail */
+ if (0 == xdr->tail[0].iov_len)
+ goto done;
+
+ vec->count++;
+ vec->sge[sge_no].iov_len = xdr->tail[0].iov_len;
+
+ if (((unsigned long)xdr->tail[0].iov_base & PAGE_MASK) ==
+ ((unsigned long)xdr->head[0].iov_base & PAGE_MASK)) {
+ /*
+ * If head and tail use the same page, we don't need
+ * to map it again.
+ */
+ vec->sge[sge_no].iov_base = xdr->tail[0].iov_base;
+ } else {
+ void *va;
+
+ /* Map another page for the tail */
+ page_off = (unsigned long)xdr->tail[0].iov_base & ~PAGE_MASK;
+ va = (void *)((unsigned long)xdr->tail[0].iov_base & PAGE_MASK);
+ vec->sge[sge_no].iov_base = frva + frmr->map_len + page_off;
+
+ frmr->page_list->page_list[page_no] =
+ ib_dma_map_single(xprt->sc_cm_id->device, va, PAGE_SIZE,
+ DMA_TO_DEVICE);
+ if (ib_dma_mapping_error(xprt->sc_cm_id->device,
+ frmr->page_list->page_list[page_no]))
+ goto fatal_err;
+ atomic_inc(&xprt->sc_dma_used);
+ frmr->map_len += PAGE_SIZE;
+ frmr->page_list_len++;
+ }
+
+ done:
+ if (svc_rdma_fastreg(xprt, frmr))
+ goto fatal_err;
+
+ return 0;
+
+ fatal_err:
+ printk("svcrdma: Error fast registering memory for xprt %p\n", xprt);
+ svc_rdma_put_frmr(xprt, frmr);
+ return -EIO;
+}
+
+static int map_xdr(struct svcxprt_rdma *xprt,
+ struct xdr_buf *xdr,
+ struct svc_rdma_req_map *vec)
{
int sge_max = (xdr->len+PAGE_SIZE-1) / PAGE_SIZE + 3;
int sge_no;
@@ -83,6 +201,9 @@
BUG_ON(xdr->len !=
(xdr->head[0].iov_len + xdr->page_len + xdr->tail[0].iov_len));
+ if (xprt->sc_frmr_pg_list_len)
+ return fast_reg_xdr(xprt, xdr, vec);
+
/* Skip the first sge, this is for the RPCRDMA header */
sge_no = 1;
@@ -116,9 +237,12 @@
BUG_ON(sge_no > sge_max);
vec->count = sge_no;
+ return 0;
}
/* Assumptions:
+ * - We are using FRMR
+ * - or -
* - The specified write_len can be represented in sc_max_sge * PAGE_SIZE
*/
static int send_write(struct svcxprt_rdma *xprt, struct svc_rqst *rqstp,
@@ -158,30 +282,35 @@
sge_no = 0;
/* Copy the remaining SGE */
- while (bc != 0 && xdr_sge_no < vec->count) {
- sge[sge_no].lkey = xprt->sc_phys_mr->lkey;
- sge_bytes = min((size_t)bc,
- (size_t)(vec->sge[xdr_sge_no].iov_len-sge_off));
+ while (bc != 0) {
+ sge_bytes = min_t(size_t,
+ bc, vec->sge[xdr_sge_no].iov_len-sge_off);
sge[sge_no].length = sge_bytes;
- atomic_inc(&xprt->sc_dma_used);
- sge[sge_no].addr =
- ib_dma_map_single(xprt->sc_cm_id->device,
- (void *)
- vec->sge[xdr_sge_no].iov_base + sge_off,
- sge_bytes, DMA_TO_DEVICE);
- if (dma_mapping_error(xprt->sc_cm_id->device->dma_device,
- sge[sge_no].addr))
- goto err;
+ if (!vec->frmr) {
+ sge[sge_no].addr =
+ ib_dma_map_single(xprt->sc_cm_id->device,
+ (void *)
+ vec->sge[xdr_sge_no].iov_base + sge_off,
+ sge_bytes, DMA_TO_DEVICE);
+ if (ib_dma_mapping_error(xprt->sc_cm_id->device,
+ sge[sge_no].addr))
+ goto err;
+ atomic_inc(&xprt->sc_dma_used);
+ sge[sge_no].lkey = xprt->sc_dma_lkey;
+ } else {
+ sge[sge_no].addr = (unsigned long)
+ vec->sge[xdr_sge_no].iov_base + sge_off;
+ sge[sge_no].lkey = vec->frmr->mr->lkey;
+ }
+ ctxt->count++;
+ ctxt->frmr = vec->frmr;
sge_off = 0;
sge_no++;
- ctxt->count++;
xdr_sge_no++;
+ BUG_ON(xdr_sge_no > vec->count);
bc -= sge_bytes;
}
- BUG_ON(bc != 0);
- BUG_ON(xdr_sge_no > vec->count);
-
/* Prepare WRITE WR */
memset(&write_wr, 0, sizeof write_wr);
ctxt->wr_op = IB_WR_RDMA_WRITE;
@@ -226,7 +355,10 @@
res_ary = (struct rpcrdma_write_array *)
&rdma_resp->rm_body.rm_chunks[1];
- max_write = xprt->sc_max_sge * PAGE_SIZE;
+ if (vec->frmr)
+ max_write = vec->frmr->map_len;
+ else
+ max_write = xprt->sc_max_sge * PAGE_SIZE;
/* Write chunks start at the pagelist */
for (xdr_off = rqstp->rq_res.head[0].iov_len, chunk_no = 0;
@@ -297,7 +429,10 @@
res_ary = (struct rpcrdma_write_array *)
&rdma_resp->rm_body.rm_chunks[2];
- max_write = xprt->sc_max_sge * PAGE_SIZE;
+ if (vec->frmr)
+ max_write = vec->frmr->map_len;
+ else
+ max_write = xprt->sc_max_sge * PAGE_SIZE;
/* xdr offset starts at RPC message */
for (xdr_off = 0, chunk_no = 0;
@@ -307,7 +442,6 @@
ch = &arg_ary->wc_array[chunk_no].wc_target;
write_len = min(xfer_len, ch->rs_length);
-
/* Prepare the reply chunk given the length actually
* written */
rs_offset = get_unaligned(&(ch->rs_offset));
@@ -366,6 +500,7 @@
int byte_count)
{
struct ib_send_wr send_wr;
+ struct ib_send_wr inv_wr;
int sge_no;
int sge_bytes;
int page_no;
@@ -385,27 +520,45 @@
/* Prepare the context */
ctxt->pages[0] = page;
ctxt->count = 1;
+ ctxt->frmr = vec->frmr;
+ if (vec->frmr)
+ set_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags);
+ else
+ clear_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags);
/* Prepare the SGE for the RPCRDMA Header */
- atomic_inc(&rdma->sc_dma_used);
ctxt->sge[0].addr =
ib_dma_map_page(rdma->sc_cm_id->device,
page, 0, PAGE_SIZE, DMA_TO_DEVICE);
+ if (ib_dma_mapping_error(rdma->sc_cm_id->device, ctxt->sge[0].addr))
+ goto err;
+ atomic_inc(&rdma->sc_dma_used);
+
ctxt->direction = DMA_TO_DEVICE;
+
ctxt->sge[0].length = svc_rdma_xdr_get_reply_hdr_len(rdma_resp);
- ctxt->sge[0].lkey = rdma->sc_phys_mr->lkey;
+ ctxt->sge[0].lkey = rdma->sc_dma_lkey;
/* Determine how many of our SGE are to be transmitted */
for (sge_no = 1; byte_count && sge_no < vec->count; sge_no++) {
sge_bytes = min_t(size_t, vec->sge[sge_no].iov_len, byte_count);
byte_count -= sge_bytes;
- atomic_inc(&rdma->sc_dma_used);
- ctxt->sge[sge_no].addr =
- ib_dma_map_single(rdma->sc_cm_id->device,
- vec->sge[sge_no].iov_base,
- sge_bytes, DMA_TO_DEVICE);
+ if (!vec->frmr) {
+ ctxt->sge[sge_no].addr =
+ ib_dma_map_single(rdma->sc_cm_id->device,
+ vec->sge[sge_no].iov_base,
+ sge_bytes, DMA_TO_DEVICE);
+ if (ib_dma_mapping_error(rdma->sc_cm_id->device,
+ ctxt->sge[sge_no].addr))
+ goto err;
+ atomic_inc(&rdma->sc_dma_used);
+ ctxt->sge[sge_no].lkey = rdma->sc_dma_lkey;
+ } else {
+ ctxt->sge[sge_no].addr = (unsigned long)
+ vec->sge[sge_no].iov_base;
+ ctxt->sge[sge_no].lkey = vec->frmr->mr->lkey;
+ }
ctxt->sge[sge_no].length = sge_bytes;
- ctxt->sge[sge_no].lkey = rdma->sc_phys_mr->lkey;
}
BUG_ON(byte_count != 0);
@@ -417,11 +570,16 @@
ctxt->pages[page_no+1] = rqstp->rq_respages[page_no];
ctxt->count++;
rqstp->rq_respages[page_no] = NULL;
- /* If there are more pages than SGE, terminate SGE list */
+ /*
+ * If there are more pages than SGE, terminate SGE
+ * list so that svc_rdma_unmap_dma doesn't attempt to
+ * unmap garbage.
+ */
if (page_no+1 >= sge_no)
ctxt->sge[page_no+1].length = 0;
}
BUG_ON(sge_no > rdma->sc_max_sge);
+ BUG_ON(sge_no > ctxt->count);
memset(&send_wr, 0, sizeof send_wr);
ctxt->wr_op = IB_WR_SEND;
send_wr.wr_id = (unsigned long)ctxt;
@@ -429,12 +587,26 @@
send_wr.num_sge = sge_no;
send_wr.opcode = IB_WR_SEND;
send_wr.send_flags = IB_SEND_SIGNALED;
+ if (vec->frmr) {
+ /* Prepare INVALIDATE WR */
+ memset(&inv_wr, 0, sizeof inv_wr);
+ inv_wr.opcode = IB_WR_LOCAL_INV;
+ inv_wr.send_flags = IB_SEND_SIGNALED;
+ inv_wr.ex.invalidate_rkey =
+ vec->frmr->mr->lkey;
+ send_wr.next = &inv_wr;
+ }
ret = svc_rdma_send(rdma, &send_wr);
if (ret)
- svc_rdma_put_context(ctxt, 1);
+ goto err;
- return ret;
+ return 0;
+
+ err:
+ svc_rdma_put_frmr(rdma, vec->frmr);
+ svc_rdma_put_context(ctxt, 1);
+ return -EIO;
}
void svc_rdma_prep_reply_hdr(struct svc_rqst *rqstp)
@@ -477,8 +649,9 @@
ctxt = svc_rdma_get_context(rdma);
ctxt->direction = DMA_TO_DEVICE;
vec = svc_rdma_get_req_map();
- xdr_to_sge(rdma, &rqstp->rq_res, vec);
-
+ ret = map_xdr(rdma, &rqstp->rq_res, vec);
+ if (ret)
+ goto err0;
inline_bytes = rqstp->rq_res.len;
/* Create the RDMA response header */
@@ -498,7 +671,7 @@
if (ret < 0) {
printk(KERN_ERR "svcrdma: failed to send write chunks, rc=%d\n",
ret);
- goto error;
+ goto err1;
}
inline_bytes -= ret;
@@ -508,7 +681,7 @@
if (ret < 0) {
printk(KERN_ERR "svcrdma: failed to send reply chunks, rc=%d\n",
ret);
- goto error;
+ goto err1;
}
inline_bytes -= ret;
@@ -517,9 +690,11 @@
svc_rdma_put_req_map(vec);
dprintk("svcrdma: send_reply returns %d\n", ret);
return ret;
- error:
+
+ err1:
+ put_page(res_page);
+ err0:
svc_rdma_put_req_map(vec);
svc_rdma_put_context(ctxt, 0);
- put_page(res_page);
return ret;
}