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Commit d8111028 authored by Erez Zilber's avatar Erez Zilber Committed by Roland Dreier
Browse files

IB/iser: Do not use FMR for a single dma entry sg 



Fast Memory Registration (fmr) is used to register for rdma an sg whose
elements are not linearly sequential after dma mapping.

The IB verbs layer provides an "all dma memory MR (memory region)" which
can be used for RDMA-ing a dma linearly sequential buffer.

Change the code to use the dma mr instead of doing fmr when dma mapping
produces a single dma entry sg.

Signed-off-by: default avatarErez Zilber <erezz@voltaire.com>
Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
parent e981f1d4

drivers/infiniband/ulp/iser/iscsi_iser.h

+1 −0
Original line number Diff line number Diff line
@@ -175,6 +175,7 @@ struct iser_mem_reg { 
	u64  va;

	u64  len;

	void *mem_h;

	int  is_fmr;

};



struct iser_regd_buf {

drivers/infiniband/ulp/iser/iser_memory.c

+34 −14
Original line number Diff line number Diff line
@@ -56,7 +56,7 @@ int iser_regd_buff_release(struct iser_regd_buf *regd_buf) 
	if ((atomic_read(&regd_buf->ref_count) == 0) ||

	    atomic_dec_and_test(&regd_buf->ref_count)) {

		/* if we used the dma mr, unreg is just NOP */

		if (regd_buf->reg.rkey != 0)

		if (regd_buf->reg.is_fmr)

			iser_unreg_mem(&regd_buf->reg);



		if (regd_buf->dma_addr) {
@@ -91,9 +91,9 @@ void iser_reg_single(struct iser_device *device, 
	BUG_ON(dma_mapping_error(dma_addr));



	regd_buf->reg.lkey = device->mr->lkey;

	regd_buf->reg.rkey = 0; /* indicate there's no need to unreg */

	regd_buf->reg.len  = regd_buf->data_size;

	regd_buf->reg.va   = dma_addr;

	regd_buf->reg.is_fmr = 0;



	regd_buf->dma_addr  = dma_addr;

	regd_buf->direction = direction;
@@ -379,11 +379,13 @@ int iser_reg_rdma_mem(struct iscsi_iser_cmd_task *iser_ctask, 
		      enum   iser_data_dir        cmd_dir)

{

	struct iser_conn     *ib_conn = iser_ctask->iser_conn->ib_conn;

	struct iser_device   *device = ib_conn->device;

	struct iser_data_buf *mem = &iser_ctask->data[cmd_dir];

	struct iser_regd_buf *regd_buf;

	int aligned_len;

	int err;

	int i;

	struct scatterlist *sg;



	regd_buf = &iser_ctask->rdma_regd[cmd_dir];
@@ -399,6 +401,23 @@ int iser_reg_rdma_mem(struct iscsi_iser_cmd_task *iser_ctask, 
		mem = &iser_ctask->data_copy[cmd_dir];

	}



	/* if there a single dma entry, FMR is not needed */

	if (mem->dma_nents == 1) {

		sg = (struct scatterlist *)mem->buf;



		regd_buf->reg.lkey = device->mr->lkey;

		regd_buf->reg.rkey = device->mr->rkey;

		regd_buf->reg.len  = sg_dma_len(&sg[0]);

		regd_buf->reg.va   = sg_dma_address(&sg[0]);

		regd_buf->reg.is_fmr = 0;



		iser_dbg("PHYSICAL Mem.register: lkey: 0x%08X rkey: 0x%08X  "

			 "va: 0x%08lX sz: %ld]\n",

			 (unsigned int)regd_buf->reg.lkey,

			 (unsigned int)regd_buf->reg.rkey,

			 (unsigned long)regd_buf->reg.va,

			 (unsigned long)regd_buf->reg.len);

	} else { /* use FMR for multiple dma entries */

		iser_page_vec_build(mem, ib_conn->page_vec);

		err = iser_reg_page_vec(ib_conn, ib_conn->page_vec, &regd_buf->reg);

		if (err) {
@@ -408,11 +427,12 @@ int iser_reg_rdma_mem(struct iscsi_iser_cmd_task *iser_ctask, 
			iser_err("page_vec: data_size = 0x%x, length = %d, offset = 0x%x\n",

				 ib_conn->page_vec->data_size, ib_conn->page_vec->length,

				 ib_conn->page_vec->offset);

		for (i=0 ; i<ib_conn->page_vec->length ; i++) {

			iser_err("page_vec[%d] = 0x%lx\n", i, ib_conn->page_vec->pages[i]);

		}

			for (i=0 ; i<ib_conn->page_vec->length ; i++)

				iser_err("page_vec[%d] = 0x%llx\n", i,

					 (unsigned long long) ib_conn->page_vec->pages[i]);

			return err;

		}

	}



	/* take a reference on this regd buf such that it will not be released *

	 * (eg in send dto completion) before we get the scsi response         */

drivers/infiniband/ulp/iser/iser_verbs.c

+4 −2
Original line number Diff line number Diff line
@@ -88,8 +88,9 @@ static int iser_create_device_ib_res(struct iser_device *device) 
		     iser_cq_tasklet_fn,

		     (unsigned long)device);



	device->mr = ib_get_dma_mr(device->pd,

				   IB_ACCESS_LOCAL_WRITE);

	device->mr = ib_get_dma_mr(device->pd, IB_ACCESS_LOCAL_WRITE |

				   IB_ACCESS_REMOTE_WRITE |

				   IB_ACCESS_REMOTE_READ);

	if (IS_ERR(device->mr))

		goto dma_mr_err;
@@ -606,6 +607,7 @@ int iser_reg_page_vec(struct iser_conn *ib_conn, 
	mem_reg->rkey  = mem->fmr->rkey;

	mem_reg->len   = page_vec->length * SIZE_4K;

	mem_reg->va    = io_addr;

	mem_reg->is_fmr = 1;

	mem_reg->mem_h = (void *)mem;



	mem_reg->va   += page_vec->offset;