kfifo: fix warn_unused_result

Fix the "ignoring return value of '...', declared with attribute
warn_unused_result" compiler warning in several users of the new kfifo
API.

It removes the __must_check attribute from kfifo_in() and
kfifo_in_locked() which must not necessary performed.

Fix the allocation bug in the nozomi driver file, by moving out the
kfifo_alloc from the interrupt handler into the probe function.

Fix the kfifo_out() and kfifo_out_locked() users to handle a unexpected
end of fifo.

Signed-off-by: Stefani Seibold <stefani@seibold.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/scsi/libiscsi_tcp.c b/drivers/scsi/libiscsi_tcp.c
index d51ffec..db6856c 100644
--- a/drivers/scsi/libiscsi_tcp.c
+++ b/drivers/scsi/libiscsi_tcp.c
@@ -990,8 +990,13 @@
 		}
 
 		if (r2t == NULL) {
-			kfifo_out(&tcp_task->r2tqueue,
-				    (void *)&tcp_task->r2t, sizeof(void *));
+			if (kfifo_out(&tcp_task->r2tqueue,
+			    (void *)&tcp_task->r2t, sizeof(void *)) !=
+			    sizeof(void *)) {
+				WARN_ONCE(1, "unexpected fifo state");
+				r2t = NULL;
+			}
+
 			r2t = tcp_task->r2t;
 		}
 		spin_unlock_bh(&session->lock);