2008-09-24 20:25:57

by [email protected]

[permalink] [raw]
Subject: Re: [PATCH 04/10] svcrdma: Add a service to register a Fast Reg MR with the device

On Tue, Sep 16, 2008 at 06:34:33AM -0500, Tom Tucker wrote:
> Fast Reg MR introduces a new WR type. Add a service to register the
> region with the adapter and update the completion handling to support
> completions with a NULL WR context.
>
> Signed-off-by: Tom Tucker <[email protected]>
>
> ---
> include/linux/sunrpc/svc_rdma.h | 1 +
> net/sunrpc/xprtrdma/svc_rdma_transport.c | 53 ++++++++++++++++++++++++++---
> 2 files changed, 48 insertions(+), 6 deletions(-)
>
> diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
> index 100754e..6899b71 100644
> --- a/include/linux/sunrpc/svc_rdma.h
> +++ b/include/linux/sunrpc/svc_rdma.h
> @@ -219,6 +219,7 @@ extern struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *);
> extern void svc_rdma_put_context(struct svc_rdma_op_ctxt *, int);
> extern struct svc_rdma_req_map *svc_rdma_get_req_map(void);
> extern void svc_rdma_put_req_map(struct svc_rdma_req_map *);
> +extern int svc_rdma_fastreg(struct svcxprt_rdma *, struct svc_rdma_fastreg_mr *);
> extern struct svc_rdma_fastreg_mr *svc_rdma_get_frmr(struct svcxprt_rdma *);
> extern void svc_rdma_put_frmr(struct svcxprt_rdma *,
> struct svc_rdma_fastreg_mr *);
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
> index 8586c7d..b8c642d 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
> @@ -344,10 +344,6 @@ static void sq_cq_reap(struct svcxprt_rdma *xprt)
> ib_req_notify_cq(xprt->sc_sq_cq, IB_CQ_NEXT_COMP);
> atomic_inc(&rdma_stat_sq_poll);
> while ((ret = ib_poll_cq(cq, 1, &wc)) > 0) {
> - ctxt = (struct svc_rdma_op_ctxt *)(unsigned long)wc.wr_id;
> - xprt = ctxt->xprt;

So this assignment to xprt was always unnecessary?

> -
> - svc_rdma_unmap_dma(ctxt);
> if (wc.status != IB_WC_SUCCESS)
> /* Close the transport */
> set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
> @@ -356,6 +352,11 @@ static void sq_cq_reap(struct svcxprt_rdma *xprt)
> atomic_dec(&xprt->sc_sq_count);
> wake_up(&xprt->sc_send_wait);
>
> + ctxt = (struct svc_rdma_op_ctxt *)(unsigned long)wc.wr_id;
> + if (!ctxt)
> + goto skip_it;
> + svc_rdma_unmap_dma(ctxt);
> +
> switch (ctxt->wr_op) {
> case IB_WR_SEND:
> svc_rdma_put_context(ctxt, 1);
> @@ -385,6 +386,7 @@ static void sq_cq_reap(struct svcxprt_rdma *xprt)
> wc.opcode, wc.status);
> break;
> }
> + skip_it:

That big switch we just goto'd over might be a candidate for
encapsulating in a separate function.

--b.

> svc_xprt_put(&xprt->sc_xprt);
> }
>
> @@ -1203,6 +1205,47 @@ static int svc_rdma_has_wspace(struct svc_xprt *xprt)
> return 1;
> }
>
> +/*
> + * Attempt to register the kvec representing the RPC memory with the
> + * device.
> + *
> + * Returns:
> + * NULL : The device does not support fastreg or there were no more
> + * fastreg mr.
> + * frmr : The kvec register request was successfully posted.
> + * <0 : An error was encountered attempting to register the kvec.
> + */
> +int svc_rdma_fastreg(struct svcxprt_rdma *xprt,
> + struct svc_rdma_fastreg_mr *frmr)
> +{
> + struct ib_send_wr fastreg_wr;
> + u8 key;
> + int ret;
> +
> + /* Bump the key */
> + key = (u8)(frmr->mr->lkey & 0x000000FF);
> + ib_update_fast_reg_key(frmr->mr, ++key);
> +
> + /* Prepare FASTREG WR */
> + memset(&fastreg_wr, 0, sizeof fastreg_wr);
> + fastreg_wr.opcode = IB_WR_FAST_REG_MR;
> + fastreg_wr.send_flags = IB_SEND_SIGNALED;
> + fastreg_wr.wr.fast_reg.iova_start = (unsigned long)frmr->kva;
> + fastreg_wr.wr.fast_reg.page_list = frmr->page_list;
> + fastreg_wr.wr.fast_reg.page_list_len = frmr->page_list_len;
> + fastreg_wr.wr.fast_reg.page_shift = PAGE_SHIFT;
> + fastreg_wr.wr.fast_reg.length = frmr->map_len;
> + fastreg_wr.wr.fast_reg.access_flags = frmr->access_flags;
> + fastreg_wr.wr.fast_reg.rkey = frmr->mr->lkey;
> + ret = svc_rdma_send(xprt, &fastreg_wr);
> + dprintk("svcrdma:%s: reg lkey %08x kva %p mrlen %lu pages %d ret %d\n",
> + __func__, frmr->mr->lkey, frmr->kva, frmr->map_len,
> + frmr->page_list_len,
> + ret);
> +
> + return ret;
> +}
> +
> int svc_rdma_send(struct svcxprt_rdma *xprt, struct ib_send_wr *wr)
> {
> struct ib_send_wr *bad_wr;
> @@ -1212,8 +1255,6 @@ int svc_rdma_send(struct svcxprt_rdma *xprt, struct ib_send_wr *wr)
> return -ENOTCONN;
>
> BUG_ON(wr->send_flags != IB_SEND_SIGNALED);
> - BUG_ON(((struct svc_rdma_op_ctxt *)(unsigned long)wr->wr_id)->wr_op !=
> - wr->opcode);
> /* If the SQ is full, wait until an SQ entry is available */
> while (1) {
> spin_lock_bh(&xprt->sc_lock);


2008-09-25 13:31:18

by Tom Tucker

[permalink] [raw]
Subject: Re: [PATCH 04/10] svcrdma: Add a service to register a Fast Reg MR with the device

J. Bruce Fields wrote:
> On Tue, Sep 16, 2008 at 06:34:33AM -0500, Tom Tucker wrote:
>> Fast Reg MR introduces a new WR type. Add a service to register the
>> region with the adapter and update the completion handling to support
>> completions with a NULL WR context.
>>
>> Signed-off-by: Tom Tucker <[email protected]>
>>
>> ---
>> include/linux/sunrpc/svc_rdma.h | 1 +
>> net/sunrpc/xprtrdma/svc_rdma_transport.c | 53 ++++++++++++++++++++++++++---
>> 2 files changed, 48 insertions(+), 6 deletions(-)
>>
>> diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
>> index 100754e..6899b71 100644
>> --- a/include/linux/sunrpc/svc_rdma.h
>> +++ b/include/linux/sunrpc/svc_rdma.h
>> @@ -219,6 +219,7 @@ extern struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *);
>> extern void svc_rdma_put_context(struct svc_rdma_op_ctxt *, int);
>> extern struct svc_rdma_req_map *svc_rdma_get_req_map(void);
>> extern void svc_rdma_put_req_map(struct svc_rdma_req_map *);
>> +extern int svc_rdma_fastreg(struct svcxprt_rdma *, struct svc_rdma_fastreg_mr *);
>> extern struct svc_rdma_fastreg_mr *svc_rdma_get_frmr(struct svcxprt_rdma *);
>> extern void svc_rdma_put_frmr(struct svcxprt_rdma *,
>> struct svc_rdma_fastreg_mr *);
>> diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
>> index 8586c7d..b8c642d 100644
>> --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
>> +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
>> @@ -344,10 +344,6 @@ static void sq_cq_reap(struct svcxprt_rdma *xprt)
>> ib_req_notify_cq(xprt->sc_sq_cq, IB_CQ_NEXT_COMP);
>> atomic_inc(&rdma_stat_sq_poll);
>> while ((ret = ib_poll_cq(cq, 1, &wc)) > 0) {
>> - ctxt = (struct svc_rdma_op_ctxt *)(unsigned long)wc.wr_id;
>> - xprt = ctxt->xprt;
>
> So this assignment to xprt was always unnecessary?
>

Yes, the correct xprt is passed in as an argument.

BUG_ON(ctxt->xprt != xprt)

>> -
>> - svc_rdma_unmap_dma(ctxt);
>> if (wc.status != IB_WC_SUCCESS)
>> /* Close the transport */
>> set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
>> @@ -356,6 +352,11 @@ static void sq_cq_reap(struct svcxprt_rdma *xprt)
>> atomic_dec(&xprt->sc_sq_count);
>> wake_up(&xprt->sc_send_wait);
>>
>> + ctxt = (struct svc_rdma_op_ctxt *)(unsigned long)wc.wr_id;
>> + if (!ctxt)
>> + goto skip_it;
>> + svc_rdma_unmap_dma(ctxt);
>> +
>> switch (ctxt->wr_op) {
>> case IB_WR_SEND:
>> svc_rdma_put_context(ctxt, 1);
>> @@ -385,6 +386,7 @@ static void sq_cq_reap(struct svcxprt_rdma *xprt)
>> wc.opcode, wc.status);
>> break;
>> }
>> + skip_it:
>
> That big switch we just goto'd over might be a candidate for
> encapsulating in a separate function.

Yes, you're right, that would look better.

>
> --b.
>
>> svc_xprt_put(&xprt->sc_xprt);
>> }
>>
>> @@ -1203,6 +1205,47 @@ static int svc_rdma_has_wspace(struct svc_xprt *xprt)
>> return 1;
>> }
>>
>> +/*
>> + * Attempt to register the kvec representing the RPC memory with the
>> + * device.
>> + *
>> + * Returns:
>> + * NULL : The device does not support fastreg or there were no more
>> + * fastreg mr.
>> + * frmr : The kvec register request was successfully posted.
>> + * <0 : An error was encountered attempting to register the kvec.
>> + */
>> +int svc_rdma_fastreg(struct svcxprt_rdma *xprt,
>> + struct svc_rdma_fastreg_mr *frmr)
>> +{
>> + struct ib_send_wr fastreg_wr;
>> + u8 key;
>> + int ret;
>> +
>> + /* Bump the key */
>> + key = (u8)(frmr->mr->lkey & 0x000000FF);
>> + ib_update_fast_reg_key(frmr->mr, ++key);
>> +
>> + /* Prepare FASTREG WR */
>> + memset(&fastreg_wr, 0, sizeof fastreg_wr);
>> + fastreg_wr.opcode = IB_WR_FAST_REG_MR;
>> + fastreg_wr.send_flags = IB_SEND_SIGNALED;
>> + fastreg_wr.wr.fast_reg.iova_start = (unsigned long)frmr->kva;
>> + fastreg_wr.wr.fast_reg.page_list = frmr->page_list;
>> + fastreg_wr.wr.fast_reg.page_list_len = frmr->page_list_len;
>> + fastreg_wr.wr.fast_reg.page_shift = PAGE_SHIFT;
>> + fastreg_wr.wr.fast_reg.length = frmr->map_len;
>> + fastreg_wr.wr.fast_reg.access_flags = frmr->access_flags;
>> + fastreg_wr.wr.fast_reg.rkey = frmr->mr->lkey;
>> + ret = svc_rdma_send(xprt, &fastreg_wr);
>> + dprintk("svcrdma:%s: reg lkey %08x kva %p mrlen %lu pages %d ret %d\n",
>> + __func__, frmr->mr->lkey, frmr->kva, frmr->map_len,
>> + frmr->page_list_len,
>> + ret);
>> +
>> + return ret;
>> +}
>> +
>> int svc_rdma_send(struct svcxprt_rdma *xprt, struct ib_send_wr *wr)
>> {
>> struct ib_send_wr *bad_wr;
>> @@ -1212,8 +1255,6 @@ int svc_rdma_send(struct svcxprt_rdma *xprt, struct ib_send_wr *wr)
>> return -ENOTCONN;
>>
>> BUG_ON(wr->send_flags != IB_SEND_SIGNALED);
>> - BUG_ON(((struct svc_rdma_op_ctxt *)(unsigned long)wr->wr_id)->wr_op !=
>> - wr->opcode);
>> /* If the SQ is full, wait until an SQ entry is available */
>> while (1) {
>> spin_lock_bh(&xprt->sc_lock);