drbd: remove usage of list iterator variable after loop

In preparation to limit the scope of a list iterator to the list
traversal loop, use a dedicated pointer to iterate through the list [1].

Since that variable should not be used past the loop iteration, a
separate variable is used to 'remember the current location within the
loop'.

To either continue iterating from that position or skip the iteration
(if the previous iteration was complete) list_prepare_entry() is used.

Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/
Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
Link: https://lore.kernel.org/r/20220331220349.885126-1-jakobkoschel@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 6f45081..6831ddb 100644 (file)
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -171,7 +171,7 @@ void tl_release(struct drbd_connection *connection, unsigned int barrier_nr,
                unsigned int set_size)
 {
        struct drbd_request *r;
-       struct drbd_request *req = NULL;
+       struct drbd_request *req = NULL, *tmp = NULL;
        int expect_epoch = 0;
        int expect_size = 0;
 
@@ -225,8 +225,11 @@ void tl_release(struct drbd_connection *connection, unsigned int barrier_nr,
         * to catch requests being barrier-acked "unexpectedly".
         * It usually should find the same req again, or some READ preceding it. */
        list_for_each_entry(req, &connection->transfer_log, tl_requests)
-               if (req->epoch == expect_epoch)
+               if (req->epoch == expect_epoch) {
+                       tmp = req;
                        break;
+               }
+       req = list_prepare_entry(tmp, &connection->transfer_log, tl_requests);
        list_for_each_entry_safe_from(req, r, &connection->transfer_log, tl_requests) {
                if (req->epoch != expect_epoch)
                        break;