IB/isert: Align target max I/O size to initiator size

Since the Linux iser initiator default max I/O size set to 512KB and since
there is no handshake procedure for this size in iser protocol, set the
default max IO size of the target to 512KB as well.

For changing the default values, there is a module parameter for both
drivers.

Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Alaa Hleihel <[email protected]>
Reviewed-by: Israel Rukshin <[email protected]>
Signed-off-by: Max Gurtovoy <[email protected]>
Acked-by: Sagi Grimberg <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>

drivers/infiniband/ulp/isert/ib_isert.c

@@ -35,10 +35,10 @@ static const struct kernel_param_ops sg_tablesize_ops = {
 	.get = param_get_int,
 };
 
-static int isert_sg_tablesize = ISCSI_ISER_DEF_SG_TABLESIZE;
+static int isert_sg_tablesize = ISCSI_ISER_MIN_SG_TABLESIZE;
 module_param_cb(sg_tablesize, &sg_tablesize_ops, &isert_sg_tablesize, 0644);
 MODULE_PARM_DESC(sg_tablesize,
-		 "Number of gather/scatter entries in a single scsi command, should >= 128 (default: 256, max: 4096)");
+		 "Number of gather/scatter entries in a single scsi command, should >= 128 (default: 128, max: 4096)");
 
 static DEFINE_MUTEX(device_list_mutex);
 static LIST_HEAD(device_list);

drivers/infiniband/ulp/isert/ib_isert.h

@@ -65,9 +65,6 @@
  */
 #define ISER_RX_SIZE		(ISCSI_DEF_MAX_RECV_SEG_LEN + 1024)
 
-/* Default I/O size is 1MB */
-#define ISCSI_ISER_DEF_SG_TABLESIZE 256
-
 /* Minimum I/O size is 512KB */
 #define ISCSI_ISER_MIN_SG_TABLESIZE 128