[SCSI] iscsi_tcp: make padbuf non-static

virt_to_page() call should not be used on kernel text and data
addresses.  virt_to_page() is used by sg_init_one(). So change padbuf
to be allocated within iscsi_segment.

Signed-off-by: Karen Xie <kxie@chelsio.com>
Acked-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
diff --git a/include/scsi/libiscsi_tcp.h b/include/scsi/libiscsi_tcp.h
index 83e32f6..9e3182e 100644
--- a/include/scsi/libiscsi_tcp.h
+++ b/include/scsi/libiscsi_tcp.h
@@ -39,6 +39,7 @@
 	unsigned int		total_copied;
 
 	struct hash_desc	*hash;
+	unsigned char		padbuf[ISCSI_PAD_LEN];
 	unsigned char		recv_digest[ISCSI_DIGEST_SIZE];
 	unsigned char		digest[ISCSI_DIGEST_SIZE];
 	unsigned int		digest_len;