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IB/srp: Re-enable FMR for non-page aligned buffers

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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 8f26c9ff9cd0; January 2011).

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
This commit is contained in:
Bart Van Assche 2015-08-10 17:06:29 -07:00 committed by Doug Ledford
parent e5580242aa
commit 186fbc6689
1 changed files with 5 additions and 9 deletions
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14
drivers/infiniband/ulp/srp/ib_srp.c
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@ -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;