path: root/include
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authorJens Axboe <jaxboe@fusionio.com>2010-08-23 13:52:19 +0200
committerJens Axboe <jaxboe@fusionio.com>2010-08-23 13:52:19 +0200
commit5dd531a03ad721b41911ddb32e6e0481404e7aaf (patch)
tree3d07d0aa902eb61a575bbc7cc2a57c03431e2b01 /include
parent220eb7fd984bfc7e6b4005fdf32efe9cd8af7cf2 (diff)
block: add function call to switch the IO scheduler from a driver
Currently drivers must do an elevator_exit() + elevator_init() to switch IO schedulers. There are a few problems with this: - Since commit 1abec4fdbb142e3ccb6ce99832fae42129134a96, elevator_init() requires a zeroed out q->elevator pointer. The two existing in-kernel users don't do that. - It will only work at initialization time, since using the above two-staged construct does not properly quisce the queue. So add elevator_change() which takes care of this, and convert the elv_iosched_store() sysfs interface to use this helper as well. Reported-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Reported-by: Kevin Vigor <kevin@vigor.nu> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'include')
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index 2c958f4fce1..926b50322a4 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -136,6 +136,7 @@ extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t);
extern int elevator_init(struct request_queue *, char *);
extern void elevator_exit(struct elevator_queue *);
+extern int elevator_change(struct request_queue *, const char *);
extern int elv_rq_merge_ok(struct request *, struct bio *);