Commit 6f2e565f authored by Chuck Lever's avatar Chuck Lever Committed by Trond Myklebust
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xprtrdma: Decouple frwr_wp_create from frwr_map 



frwr_wp_create is the only caller of frwr_map outside the encode
path. It registers a single 4-byte write-pad region from a stack-
local rpcrdma_mr_seg. Inlining the registration logic directly
(sg_init_table + sg_set_page + ib_dma_map_sg + ib_map_mr_sg +
IOVA mangle + reg_wr setup) eliminates the coupling that would
otherwise complicate the removal of rpcrdma_mr_seg from frwr_map's
interface.

The inlined version adds a proper error-unwind ladder: on failure,
the DMA mapping (if established) is released, ep->re_write_pad_mr is
cleared, and the MR is returned to the transport free list. The old
frwr_map-based code relied on rpcrdma_mrs_destroy at teardown to
reclaim partially-initialized MRs.

This is a one-time setup path; duplicating ~20 lines is a reasonable
tradeoff for decoupling the write-pad registration from the data-
path MR registration.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
parent 765bde47

net/sunrpc/xprtrdma/frwr_ops.c

+50 −7
Original line number Diff line number Diff line
@@ -669,9 +669,13 @@ void frwr_unmap_async(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req) 
 */

int frwr_wp_create(struct rpcrdma_xprt *r_xprt)

{

	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;

	struct rpcrdma_ep *ep = r_xprt->rx_ep;

	struct rpcrdma_mr_seg seg;

	struct ib_reg_wr *reg_wr;

	struct rpcrdma_mr *mr;

	struct ib_mr *ibmr;

	int dma_nents;

	int ret;



	mr = rpcrdma_mr_get(r_xprt);

	if (!mr)
@@ -679,11 +683,39 @@ int frwr_wp_create(struct rpcrdma_xprt *r_xprt) 
	mr->mr_req = NULL;

	ep->re_write_pad_mr = mr;



	seg.mr_len = XDR_UNIT;

	seg.mr_page = virt_to_page(ep->re_write_pad);

	seg.mr_offset = offset_in_page(ep->re_write_pad);

	if (IS_ERR(frwr_map(r_xprt, &seg, 1, true, xdr_zero, mr)))

		return -EIO;

	sg_init_table(mr->mr_sg, 1);

	sg_set_page(mr->mr_sg, virt_to_page(ep->re_write_pad),

		    XDR_UNIT, offset_in_page(ep->re_write_pad));



	mr->mr_dir = DMA_FROM_DEVICE;

	mr->mr_nents = 1;

	dma_nents = ib_dma_map_sg(ep->re_id->device, mr->mr_sg,

				  mr->mr_nents, mr->mr_dir);

	if (!dma_nents) {

		ret = -EIO;

		goto out_mr;

	}

	mr->mr_device = ep->re_id->device;



	ibmr = mr->mr_ibmr;

	if (ib_map_mr_sg(ibmr, mr->mr_sg, dma_nents, NULL,

			 PAGE_SIZE) != dma_nents) {

		ret = -EIO;

		goto out_unmap;

	}



	/* IOVA is not tagged with an XID; the write-pad is not RPC-specific. */

	ib_update_fast_reg_key(ibmr, ib_inc_rkey(ibmr->rkey));



	reg_wr = &mr->mr_regwr;

	reg_wr->mr = ibmr;

	reg_wr->key = ibmr->rkey;

	reg_wr->access = IB_ACCESS_REMOTE_WRITE | IB_ACCESS_LOCAL_WRITE;



	mr->mr_handle = ibmr->rkey;

	mr->mr_length = ibmr->length;

	mr->mr_offset = ibmr->iova;



	trace_xprtrdma_mr_fastreg(mr);



	mr->mr_cqe.done = frwr_wc_fastreg;
@@ -693,5 +725,16 @@ int frwr_wp_create(struct rpcrdma_xprt *r_xprt) 
	mr->mr_regwr.wr.opcode = IB_WR_REG_MR;

	mr->mr_regwr.wr.send_flags = 0;



	return ib_post_send(ep->re_id->qp, &mr->mr_regwr.wr, NULL);

	ret = ib_post_send(ep->re_id->qp, &mr->mr_regwr.wr, NULL);

	if (!ret)

		return 0;



out_unmap:

	frwr_mr_unmap(mr);

out_mr:

	ep->re_write_pad_mr = NULL;

	spin_lock(&buf->rb_lock);

	rpcrdma_mr_push(mr, &buf->rb_mrs);

	spin_unlock(&buf->rb_lock);

	return ret;

}