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Commit 186fbc66 authored by Bart Van Assche's avatar Bart Van Assche Committed by Doug Ledford
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IB/srp: Re-enable FMR for non-page aligned buffers 

During a discussion in 2011 nobody recalled why FMR was not used for
non-page aligned buffers (see also
http://thread.gmane.org/gmane.linux.drivers.rdma/7149

). Re-enable FMR
for such buffers. For the reason why the srp_map_fmr() function needs
to be modified, see also patch "IB/srp: rework mapping engine to use
multiple FMR entries" (commit ID 8f26c9ff; January 2011).

Signed-off-by: default avatarBart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: default avatarDoug Ledford <dledford@redhat.com>
parent e5580242

drivers/infiniband/ulp/srp/ib_srp.c

+5 −9
Original line number Diff line number Diff line
@@ -1272,6 +1272,8 @@ static void srp_map_desc(struct srp_map_state *state, dma_addr_t dma_addr, 
static int srp_map_finish_fmr(struct srp_map_state *state,

			      struct srp_rdma_ch *ch)

{

	struct srp_target_port *target = ch->target;

	struct srp_device *dev = target->srp_host->srp_dev;

	struct ib_pool_fmr *fmr;

	u64 io_addr = 0;
@@ -1283,7 +1285,8 @@ static int srp_map_finish_fmr(struct srp_map_state *state, 
	*state->next_fmr++ = fmr;

	state->nmdesc++;



	srp_map_desc(state, 0, state->dma_len, fmr->fmr->rkey);

	srp_map_desc(state, state->base_dma_addr & ~dev->mr_page_mask,

		     state->dma_len, fmr->fmr->rkey);



	return 0;

}
@@ -1390,14 +1393,7 @@ static int srp_map_sg_entry(struct srp_map_state *state, 
		return 0;

	}



	/*

	 * Since not all RDMA HW drivers support non-zero page offsets for

	 * FMR, if we start at an offset into a page, don't merge into the

	 * current FMR mapping. Finish it out, and use the kernel's MR for

	 * this sg entry.

	 */

	if ((!dev->use_fast_reg && dma_addr & ~dev->mr_page_mask) ||

	    dma_len > dev->mr_max_size) {

	if (dma_len > dev->mr_max_size) {

		ret = srp_finish_mapping(state, ch);

		if (ret)

			return ret;