block: kill swap_io_context()
It blindly copies everything in the io_context, including the lock.
That doesn't work so well for either lock ordering or lockdep.
There seems zero point in swapping io contexts on a request to request
merge, so the best point of action is to just remove it.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/as-iosched.c b/block/as-iosched.c
index 612d640..8c39467 100644
--- a/block/as-iosched.c
+++ b/block/as-iosched.c
@@ -1268,22 +1268,8 @@
*/
if (!list_empty(&req->queuelist) && !list_empty(&next->queuelist)) {
if (time_before(rq_fifo_time(next), rq_fifo_time(req))) {
- struct io_context *rioc = RQ_IOC(req);
- struct io_context *nioc = RQ_IOC(next);
-
list_move(&req->queuelist, &next->queuelist);
rq_set_fifo_time(req, rq_fifo_time(next));
- /*
- * Don't copy here but swap, because when anext is
- * removed below, it must contain the unused context
- */
- if (rioc != nioc) {
- double_spin_lock(&rioc->lock, &nioc->lock,
- rioc < nioc);
- swap_io_context(&rioc, &nioc);
- double_spin_unlock(&rioc->lock, &nioc->lock,
- rioc < nioc);
- }
}
}
diff --git a/block/blk-ioc.c b/block/blk-ioc.c
index 6d16755..80245dc 100644
--- a/block/blk-ioc.c
+++ b/block/blk-ioc.c
@@ -176,15 +176,6 @@
}
EXPORT_SYMBOL(copy_io_context);
-void swap_io_context(struct io_context **ioc1, struct io_context **ioc2)
-{
- struct io_context *temp;
- temp = *ioc1;
- *ioc1 = *ioc2;
- *ioc2 = temp;
-}
-EXPORT_SYMBOL(swap_io_context);
-
int __init blk_ioc_init(void)
{
iocontext_cachep = kmem_cache_create("blkdev_ioc",
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index cf170391..90392a9 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -39,7 +39,6 @@
struct io_context *get_io_context(gfp_t gfp_flags, int node);
struct io_context *alloc_io_context(gfp_t gfp_flags, int node);
void copy_io_context(struct io_context **pdst, struct io_context **psrc);
-void swap_io_context(struct io_context **ioc1, struct io_context **ioc2);
struct request;
typedef void (rq_end_io_fn)(struct request *, int);