[PATCH] stop elv_unregister() from rogering other iosched's data, fix locking
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/block/as-iosched.c b/block/as-iosched.c
index 8da3cf6..d2ee2af 100644
--- a/block/as-iosched.c
+++ b/block/as-iosched.c
@@ -195,6 +195,12 @@
kfree(aic);
}
+static void as_trim(struct io_context *ioc)
+{
+ kfree(ioc->aic);
+ ioc->aic = NULL;
+}
+
/* Called when the task exits */
static void exit_as_io_context(struct as_io_context *aic)
{
@@ -1860,6 +1866,7 @@
.elevator_may_queue_fn = as_may_queue,
.elevator_init_fn = as_init_queue,
.elevator_exit_fn = as_exit_queue,
+ .trim = as_trim,
},
.elevator_ktype = &as_ktype,
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 521c56d..7102baf 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1211,6 +1211,13 @@
kmem_cache_free(cfq_ioc_pool, cic);
}
+static void cfq_trim(struct io_context *ioc)
+{
+ ioc->set_ioprio = NULL;
+ if (ioc->cic)
+ cfq_free_io_context(ioc->cic);
+}
+
/*
* Called with interrupts disabled
*/
@@ -2472,6 +2479,7 @@
.elevator_may_queue_fn = cfq_may_queue,
.elevator_init_fn = cfq_init_queue,
.elevator_exit_fn = cfq_exit_queue,
+ .trim = cfq_trim,
},
.elevator_ktype = &cfq_ktype,
.elevator_name = "cfq",
diff --git a/block/elevator.c b/block/elevator.c
index 24b702d..0232df2 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -675,21 +675,15 @@
/*
* Iterate every thread in the process to remove the io contexts.
*/
- read_lock(&tasklist_lock);
- do_each_thread(g, p) {
- struct io_context *ioc = p->io_context;
- if (ioc && ioc->cic) {
- ioc->cic->exit(ioc->cic);
- ioc->cic->dtor(ioc->cic);
- ioc->cic = NULL;
- }
- if (ioc && ioc->aic) {
- ioc->aic->exit(ioc->aic);
- ioc->aic->dtor(ioc->aic);
- ioc->aic = NULL;
- }
- } while_each_thread(g, p);
- read_unlock(&tasklist_lock);
+ if (e->ops.trim) {
+ read_lock(&tasklist_lock);
+ do_each_thread(g, p) {
+ task_lock(p);
+ e->ops.trim(p->io_context);
+ task_unlock(p);
+ } while_each_thread(g, p);
+ read_unlock(&tasklist_lock);
+ }
spin_lock_irq(&elv_list_lock);
list_del_init(&e->list);
diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index 18cf1f3..f65766e 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -48,6 +48,7 @@
elevator_init_fn *elevator_init_fn;
elevator_exit_fn *elevator_exit_fn;
+ void (*trim)(struct io_context *);
};
#define ELV_NAME_MAX (16)