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| author | Martin K. Petersen <martin.petersen@oracle.com> | 2009-05-22 17:17:52 -0400 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2009-05-22 23:22:55 +0200 |
| commit | cd43e26f071524647e660706b784ebcbefbd2e44 (patch) | |
| tree | 11625a25ba8a7c5cd4fe41b54d53506a7982433b /block/elevator.c | |
| parent | 025146e13b63483add912706c101fb0fb6f015cc (diff) | |
| download | lwn-cd43e26f071524647e660706b784ebcbefbd2e44.tar.gz lwn-cd43e26f071524647e660706b784ebcbefbd2e44.zip | |
block: Expose stacked device queues in sysfs
Currently stacking devices do not have a queue directory in sysfs.
However, many of the I/O characteristics like sector size, maximum
request size, etc. are queue properties.
This patch enables the queue directory for MD/DM devices. The elevator
code has been modified to deal with queues that do not have an I/O
scheduler.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/elevator.c')
| -rw-r--r-- | block/elevator.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/block/elevator.c b/block/elevator.c index ebee948293eb..bd78f693fcf2 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -575,6 +575,9 @@ void elv_drain_elevator(struct request_queue *q) */ void elv_quiesce_start(struct request_queue *q) { + if (!q->elevator) + return; + queue_flag_set(QUEUE_FLAG_ELVSWITCH, q); /* @@ -1050,6 +1053,9 @@ ssize_t elv_iosched_store(struct request_queue *q, const char *name, char elevator_name[ELV_NAME_MAX]; struct elevator_type *e; + if (!q->elevator) + return count; + strlcpy(elevator_name, name, sizeof(elevator_name)); strstrip(elevator_name); @@ -1073,10 +1079,15 @@ ssize_t elv_iosched_store(struct request_queue *q, const char *name, ssize_t elv_iosched_show(struct request_queue *q, char *name) { struct elevator_queue *e = q->elevator; - struct elevator_type *elv = e->elevator_type; + struct elevator_type *elv; struct elevator_type *__e; int len = 0; + if (!q->elevator) + return sprintf(name, "none\n"); + + elv = e->elevator_type; + spin_lock(&elv_list_lock); list_for_each_entry(__e, &elv_list, list) { if (!strcmp(elv->elevator_name, __e->elevator_name)) |