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| author | Nate Diller <nate.diller@gmail.com> | 2006-01-24 10:09:14 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@suse.de> | 2006-01-24 10:09:14 +0100 |
| commit | 248d5ca5ed5feb7f1a68d213c0ff89c604a97179 (patch) | |
| tree | bf05775c34c326d11ec7789ba71071755032783d /block/elevator.c | |
| parent | 5f00397644e01adfbebafb5d0ebc01eba522709d (diff) | |
| download | lwn-248d5ca5ed5feb7f1a68d213c0ff89c604a97179.tar.gz lwn-248d5ca5ed5feb7f1a68d213c0ff89c604a97179.zip | |
[BLOCK] elevator: allow default scheduler to potentially be modular
Jens has decided that allowing the default scheduler to be a module is
a bug, and should not be allowed under kconfig. However, I find that
scenario useful for debugging, and wish for the kernel to be able to
handle this situation without OOPSing, if I enable such an option in
the .config directly. This patch dynamically checks for the presence
of the compiled-in default, and falls back to no-op, emitting a
suitable error message, when the default is not available
Tested for a range of boot options on 2.6.16-rc1-mm2.
Signed-off-by: Nate Diller <nate.diller@gmail.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
Diffstat (limited to 'block/elevator.c')
| -rw-r--r-- | block/elevator.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/block/elevator.c b/block/elevator.c index dbbea73a8b10..96a61e029ce5 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -168,10 +168,12 @@ int elevator_init(request_queue_t *q, char *name) if (name && !(e = elevator_get(name))) return -EINVAL; - if (!e && !(e = elevator_get(chosen_elevator))) { - e = elevator_get(CONFIG_DEFAULT_IOSCHED); - if (*chosen_elevator) - printk("I/O scheduler %s not found\n", chosen_elevator); + if (!e && *chosen_elevator && !(e = elevator_get(chosen_elevator))) + printk("I/O scheduler %s not found\n", chosen_elevator); + + if (!e && !(e = elevator_get(CONFIG_DEFAULT_IOSCHED))) { + printk("Default I/O scheduler not found, using no-op\n"); + e = elevator_get("noop"); } eq = kmalloc(sizeof(struct elevator_queue), GFP_KERNEL); |