Re: [PATCH] svc_rdma: use local_dma_lkey

Chuck Lever
2015-12-16T15:17:43Z

> On Dec 16, 2015, at 10:11 AM, Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org> wrote:
>
> We now alwasy have a per-PD local_dma_lkey available. Make use of that
> fact in svc_rdma and stop registering our own MR.
>
> Signed-off-by: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>

Reviewed-by: Chuck Lever <chuck.lever-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>

> ---
> include/linux/sunrpc/svc_rdma.h | 2 --
> net/sunrpc/xprtrdma/svc_rdma_backchannel.c | 2 +-
> net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 4 ++--
> net/sunrpc/xprtrdma/svc_rdma_sendto.c | 6 ++---
> net/sunrpc/xprtrdma/svc_rdma_transport.c | 36 ++++--------------------------
> 5 files changed, 10 insertions(+), 40 deletions(-)
>
> diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
> index b13513a..5322fea 100644
> --- a/include/linux/sunrpc/svc_rdma.h
> +++ b/include/linux/sunrpc/svc_rdma.h
> @@ -156,13 +156,11 @@ struct svcxprt_rdma {
> struct ib_qp *sc_qp;
> struct ib_cq *sc_rq_cq;
> struct ib_cq *sc_sq_cq;
> - struct ib_mr *sc_phys_mr; /* MR for server memory */
> int (*sc_reader)(struct svcxprt_rdma *,
> struct svc_rqst *,
> struct svc_rdma_op_ctxt *,
> int *, u32 *, u32, u32, u64, bool);
> u32 sc_dev_caps; /* distilled device caps */
> - u32 sc_dma_lkey; /* local dma key */
> unsigned int sc_frmr_pg_list_len;
> struct list_head sc_frmr_q;
> spinlock_t sc_frmr_q_lock;
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_backchannel.c b/net/sunrpc/xprtrdma/svc_rdma_backchannel.c
> index 417cec1..c428734 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_backchannel.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_backchannel.c
> @@ -128,7 +128,7 @@ static int svc_rdma_bc_sendto(struct svcxprt_rdma *rdma,
>
> ctxt->wr_op = IB_WR_SEND;
> ctxt->direction = DMA_TO_DEVICE;
> - ctxt->sge[0].lkey = rdma->sc_dma_lkey;
> + ctxt->sge[0].lkey = rdma->sc_pd->local_dma_lkey;
> ctxt->sge[0].length = sndbuf->len;
> ctxt->sge[0].addr =
> ib_dma_map_page(rdma->sc_cm_id->device, ctxt->pages[0], 0,
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> index 3dfe464..c8b8a8b 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> @@ -144,6 +144,7 @@ int rdma_read_chunk_lcl(struct svcxprt_rdma *xprt,
>
> head->arg.pages[pg_no] = rqstp->rq_arg.pages[pg_no];
> head->arg.page_len += len;
> +
> head->arg.len += len;
> if (!pg_off)
> head->count++;
> @@ -160,8 +161,7 @@ int rdma_read_chunk_lcl(struct svcxprt_rdma *xprt,
> goto err;
> atomic_inc(&xprt->sc_dma_used);
>
> - /* The lkey here is either a local dma lkey or a dma_mr lkey */
> - ctxt->sge[pno].lkey = xprt->sc_dma_lkey;
> + ctxt->sge[pno].lkey = xprt->sc_pd->local_dma_lkey;
> ctxt->sge[pno].length = len;
> ctxt->count++;
>
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> index ced3151..20bd5d4 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> @@ -265,7 +265,7 @@ static int send_write(struct svcxprt_rdma *xprt, struct svc_rqst *rqstp,
> sge[sge_no].addr))
> goto err;
> atomic_inc(&xprt->sc_dma_used);
> - sge[sge_no].lkey = xprt->sc_dma_lkey;
> + sge[sge_no].lkey = xprt->sc_pd->local_dma_lkey;
> ctxt->count++;
> sge_off = 0;
> sge_no++;
> @@ -487,7 +487,7 @@ static int send_reply(struct svcxprt_rdma *rdma,
> ctxt->count = 1;
>
> /* Prepare the SGE for the RPCRDMA Header */
> - ctxt->sge[0].lkey = rdma->sc_dma_lkey;
> + ctxt->sge[0].lkey = rdma->sc_pd->local_dma_lkey;
> ctxt->sge[0].length = svc_rdma_xdr_get_reply_hdr_len(rdma_resp);
> ctxt->sge[0].addr =
> ib_dma_map_page(rdma->sc_cm_id->device, page, 0,
> @@ -511,7 +511,7 @@ static int send_reply(struct svcxprt_rdma *rdma,
> ctxt->sge[sge_no].addr))
> goto err;
> atomic_inc(&rdma->sc_dma_used);
> - ctxt->sge[sge_no].lkey = rdma->sc_dma_lkey;
> + ctxt->sge[sge_no].lkey = rdma->sc_pd->local_dma_lkey;
> ctxt->sge[sge_no].length = sge_bytes;
> }
> if (byte_count != 0) {
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
> index abfbd02..faf4c49 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
> @@ -232,11 +232,11 @@ void svc_rdma_unmap_dma(struct svc_rdma_op_ctxt *ctxt)
> for (i = 0; i < ctxt->count && ctxt->sge[i].length; i++) {
> /*
> * Unmap the DMA addr in the SGE if the lkey matches
> - * the sc_dma_lkey, otherwise, ignore it since it is
> + * the local_dma_lkey, otherwise, ignore it since it is
> * an FRMR lkey and will be unmapped later when the
> * last WR that uses it completes.
> */
> - if (ctxt->sge[i].lkey == xprt->sc_dma_lkey) {
> + if (ctxt->sge[i].lkey == xprt->sc_pd->local_dma_lkey) {
> atomic_dec(&xprt->sc_dma_used);
> ib_dma_unmap_page(xprt->sc_cm_id->device,
> ctxt->sge[i].addr,
> @@ -698,7 +698,7 @@ int svc_rdma_post_recv(struct svcxprt_rdma *xprt, gfp_t flags)
> atomic_inc(&xprt->sc_dma_used);
> ctxt->sge[sge_no].addr = pa;
> ctxt->sge[sge_no].length = PAGE_SIZE;
> - ctxt->sge[sge_no].lkey = xprt->sc_dma_lkey;
> + ctxt->sge[sge_no].lkey = xprt->sc_pd->local_dma_lkey;
> ctxt->count = sge_no + 1;
> buflen += PAGE_SIZE;
> }
> @@ -1014,8 +1014,6 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
> struct ib_cq_init_attr cq_attr = {};
> struct ib_qp_init_attr qp_attr;
> struct ib_device *dev;
> - int uninitialized_var(dma_mr_acc);
> - int need_dma_mr = 0;
> unsigned int i;
> int ret = 0;
>
> @@ -1160,32 +1158,9 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
> !rdma_ib_or_roce(dev, newxprt->sc_cm_id->port_num))
> goto errout;
>
> - if (!(newxprt->sc_dev_caps & SVCRDMA_DEVCAP_FAST_REG) ||
> - !(dev->device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY)) {
> - need_dma_mr = 1;
> - dma_mr_acc = IB_ACCESS_LOCAL_WRITE;
> - if (rdma_protocol_iwarp(dev, newxprt->sc_cm_id->port_num) &&
> - !(newxprt->sc_dev_caps & SVCRDMA_DEVCAP_FAST_REG))
> - dma_mr_acc |= IB_ACCESS_REMOTE_WRITE;
> - }
> -
> if (rdma_protocol_iwarp(dev, newxprt->sc_cm_id->port_num))
> newxprt->sc_dev_caps |= SVCRDMA_DEVCAP_READ_W_INV;
>
> - /* Create the DMA MR if needed, otherwise, use the DMA LKEY */
> - if (need_dma_mr) {
> - /* Register all of physical memory */
> - newxprt->sc_phys_mr =
> - ib_get_dma_mr(newxprt->sc_pd, dma_mr_acc);
> - if (IS_ERR(newxprt->sc_phys_mr)) {
> - dprintk("svcrdma: Failed to create DMA MR ret=%d\n",
> - ret);
> - goto errout;
> - }
> - newxprt->sc_dma_lkey = newxprt->sc_phys_mr->lkey;
> - } else
> - newxprt->sc_dma_lkey = dev->local_dma_lkey;
> -
> /* Post receive buffers */
> for (i = 0; i < newxprt->sc_rq_depth; i++) {
> ret = svc_rdma_post_recv(newxprt, GFP_KERNEL);
> @@ -1349,9 +1324,6 @@ static void __svc_rdma_free(struct work_struct *work)
> if (rdma->sc_rq_cq && !IS_ERR(rdma->sc_rq_cq))
> ib_destroy_cq(rdma->sc_rq_cq);
>
> - if (rdma->sc_phys_mr && !IS_ERR(rdma->sc_phys_mr))
> - ib_dereg_mr(rdma->sc_phys_mr);
> -
> if (rdma->sc_pd && !IS_ERR(rdma->sc_pd))
> ib_dealloc_pd(rdma->sc_pd);
>
> @@ -1479,7 +1451,7 @@ void svc_rdma_send_error(struct svcxprt_rdma *xprt, struct rpcrdma_msg *rmsgp,
> return;
> }
> atomic_inc(&xprt->sc_dma_used);
> - ctxt->sge[0].lkey = xprt->sc_dma_lkey;
> + ctxt->sge[0].lkey = xprt->sc_pd->local_dma_lkey;
> ctxt->sge[0].length = length;
>
> /* Prepare SEND WR */
> --
> 1.9.1
>

--
Chuck Lever