IB/srp: Fix srp_map_sg_dma()

Because patch "IB/srp: Move common code into the caller" was applied
partially srp_map_sg_dma() doesn't work properly. Fix this by
applying the remainder of that patch. See also
http://thread.gmane.org/gmane.linux.drivers.rdma/35803/focus=35811.

Fixes: 3849e44d1c4b ("IB/srp: Move common code into the caller")
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Mike Marciniszyn <mike.marciniszyn@intel.com>
Cc: Sagi Grimberg <sai@grimberg.me>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Laurence Oberman <loberman@redhat.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/ulp/srp/ib_srp.c

@@ -1457,7 +1457,6 @@ static int srp_map_sg_fr(struct srp_map_state *state, struct srp_rdma_ch *ch,
 {
 	unsigned int sg_offset = 0;
 
-	state->desc = req->indirect_desc;
 	state->fr.next = req->fr_list;
 	state->fr.end = req->fr_list + ch->target->mr_per_cmd;
 	state->sg = scat;
@@ -1489,7 +1488,6 @@ static int srp_map_sg_dma(struct srp_map_state *state, struct srp_rdma_ch *ch,
 	struct scatterlist *sg;
 	int i;
 
-	state->desc = req->indirect_desc;
 	for_each_sg(scat, sg, count, i) {
 		srp_map_desc(state, ib_sg_dma_address(dev->dev, sg),
 			     ib_sg_dma_len(dev->dev, sg),
@@ -1655,6 +1653,7 @@ static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_rdma_ch *ch,
 				   target->indirect_size, DMA_TO_DEVICE);
 
 	memset(&state, 0, sizeof(state));
+	state.desc = req->indirect_desc;
 	if (dev->use_fast_reg)
 		ret = srp_map_sg_fr(&state, ch, req, scat, count);
 	else if (dev->use_fmr)