[PATCH 3/3] iscsi iser: increase sg_tablesize

[Pete Wyckoff <pw@osc.edu>]

Increase FMR limits from 512 kB to 1 MB.  This matches the limit
used by SRP which also uses FMRs for memory mapping.  Also
correct a bug where the sg_tablesize was 1 smaller than what was
allocated, by folding the "+ 1" used everywhere into the
definition of the constant.

Signed-off-by: Pete Wyckoff <pw@osc.edu>
---
 drivers/infiniband/ulp/iser/iscsi_iser.h |    3 ++-
 drivers/infiniband/ulp/iser/iser_verbs.c |    6 ++----
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.h b/drivers/infiniband/ulp/iser/iscsi_iser.h
index 1ee867b..db8f81a 100644
--- a/drivers/infiniband/ulp/iser/iscsi_iser.h
+++ b/drivers/infiniband/ulp/iser/iscsi_iser.h
@@ -87,7 +87,8 @@
 #define MASK_4K	(~(SIZE_4K-1))
 
 					/* support upto 512KB in one RDMA */
-#define ISCSI_ISER_SG_TABLESIZE         (0x80000 >> SHIFT_4K)
+/* FMR space for 1 MB of 4k-page transfers, plus 1 if not page aligned */
+#define ISCSI_ISER_SG_TABLESIZE         (((1<<20) >> SHIFT_4K) + 1)
 #define ISCSI_ISER_MAX_LUN		256
 #define ISCSI_ISER_MAX_CMD_LEN		16
 
diff --git a/drivers/infiniband/ulp/iser/iser_verbs.c b/drivers/infiniband/ulp/iser/iser_verbs.c
index 714b8db..c5b374f 100644
--- a/drivers/infiniband/ulp/iser/iser_verbs.c
+++ b/drivers/infiniband/ulp/iser/iser_verbs.c
@@ -140,7 +140,7 @@ static int iser_create_ib_conn_res(struct iser_conn *ib_conn)
 	device = ib_conn->device;
 
 	ib_conn->page_vec = kmalloc(sizeof(struct iser_page_vec) +
-				    (sizeof(u64) * (ISCSI_ISER_SG_TABLESIZE +1)),
+				    sizeof(u64) * ISCSI_ISER_SG_TABLESIZE,
 				    GFP_KERNEL);
 	if (!ib_conn->page_vec) {
 		ret = -ENOMEM;
@@ -149,9 +149,7 @@ static int iser_create_ib_conn_res(struct iser_conn *ib_conn)
 	ib_conn->page_vec->pages = (u64 *) (ib_conn->page_vec + 1);
 
 	params.page_shift        = SHIFT_4K;
-	/* when the first/last SG element are not start/end *
-	 * page aligned, the map whould be of N+1 pages     */
-	params.max_pages_per_fmr = ISCSI_ISER_SG_TABLESIZE + 1;
+	params.max_pages_per_fmr = ISCSI_ISER_SG_TABLESIZE;
 	/* make the pool size twice the max number of SCSI commands *
 	 * the ML is expected to queue, watermark for unmap at 50%  */
 	params.pool_size	 = ISCSI_DEF_XMIT_CMDS_MAX * 2;
-- 
1.5.3.8