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| author | Jens Axboe <jaxboe@fusionio.com> | 2010-08-23 13:52:19 +0200 |
|---|---|---|
| committer | Jens Axboe <jaxboe@fusionio.com> | 2010-08-23 13:52:19 +0200 |
| commit | 5dd531a03ad721b41911ddb32e6e0481404e7aaf (patch) | |
| tree | 3d07d0aa902eb61a575bbc7cc2a57c03431e2b01 /include/linux/elevator.h | |
| parent | 220eb7fd984bfc7e6b4005fdf32efe9cd8af7cf2 (diff) | |
| download | linux-5dd531a03ad721b41911ddb32e6e0481404e7aaf.tar.gz linux-5dd531a03ad721b41911ddb32e6e0481404e7aaf.tar.bz2 linux-5dd531a03ad721b41911ddb32e6e0481404e7aaf.zip | |
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/linux/elevator.h')
| -rw-r--r-- | include/linux/elevator.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/elevator.h b/include/linux/elevator.h index 2c958f4fce1e..926b50322a46 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 *); /* |