[SCSI] libiscsi, iscsi_tcp: iscsi pool cleanup

iscsi_pool_init simplified

iscsi_pool_init currently has a lot of duplicate kfree() calls it does
when some allocation fails. This patch simplifies the code a little by
using iscsi_pool_free to tear down the pool in case of an error.

iscsi_pool_init also returns a copy of the item array to the caller.
Not all callers use this array, so we make it optional.

Instead of allocating a second array and return that, allocate just one
array, of twice the size.

Update users of iscsi_pool_{init,free}

This patch drops the (now useless) second argument to
iscsi_pool_free, and updates all callers.

It also removes the ctask->r2ts array, which was never
used anyway. Since the items argument to iscsi_pool_init
is now optional, we can pass NULL instead.

Signed-off-by: Olaf Kirch <olaf.kirch@oracle.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
diff --git a/drivers/scsi/iscsi_tcp.h b/drivers/scsi/iscsi_tcp.h
index eb3784f..d49d876 100644
--- a/drivers/scsi/iscsi_tcp.h
+++ b/drivers/scsi/iscsi_tcp.h
@@ -175,9 +175,8 @@
 	uint32_t		exp_datasn;		/* expected target's R2TSN/DataSN */
 	int			data_offset;
 	struct iscsi_r2t_info	*r2t;			/* in progress R2T    */
-	struct iscsi_queue	r2tpool;
+	struct iscsi_pool	r2tpool;
 	struct kfifo		*r2tqueue;
-	struct iscsi_r2t_info	**r2ts;
 	int			digest_count;
 	uint32_t		immdigest;		/* for imm data */
 	struct iscsi_buf	immbuf;			/* for imm data digest */