Use kref for reference counter of io_context.
This patch also removes BUG_ON() for freeing unreferenced io_context.
But kref can detect it if CONFIG_DEBUG_SLAB is enabled.
Signed-off-by: Akinobu Mita <[email protected]>
CC: Jens Axboe <[email protected]>
CC: Greg KH <[email protected]>
block/cfq-iosched.c | 2 +-
block/ll_rw_blk.c | 43 +++++++++++++++++++++----------------------
include/linux/blkdev.h | 2 +-
3 files changed, 23 insertions(+), 24 deletions(-)
Index: 2.6-git/block/ll_rw_blk.c
===================================================================
--- 2.6-git.orig/block/ll_rw_blk.c
+++ 2.6-git/block/ll_rw_blk.c
@@ -3536,29 +3536,29 @@ int __init blk_dev_init(void)
/*
* IO Context helper functions
*/
+static void release_io_context(struct kref *kref)
+{
+ struct io_context *ioc = container_of(kref, struct io_context, kref);
+ struct cfq_io_context *cic;
+
+ rcu_read_lock();
+ if (ioc->aic && ioc->aic->dtor)
+ ioc->aic->dtor(ioc->aic);
+ if (ioc->cic_root.rb_node != NULL) {
+ struct rb_node *n = rb_first(&ioc->cic_root);
+ cic = rb_entry(n, struct cfq_io_context, rb_node);
+ cic->dtor(ioc);
+ }
+ rcu_read_unlock();
+ kmem_cache_free(iocontext_cachep, ioc);
+}
+
void put_io_context(struct io_context *ioc)
{
if (ioc == NULL)
return;
- BUG_ON(atomic_read(&ioc->refcount) == 0);
-
- if (atomic_dec_and_test(&ioc->refcount)) {
- struct cfq_io_context *cic;
-
- rcu_read_lock();
- if (ioc->aic && ioc->aic->dtor)
- ioc->aic->dtor(ioc->aic);
- if (ioc->cic_root.rb_node != NULL) {
- struct rb_node *n = rb_first(&ioc->cic_root);
-
- cic = rb_entry(n, struct cfq_io_context, rb_node);
- cic->dtor(ioc);
- }
- rcu_read_unlock();
-
- kmem_cache_free(iocontext_cachep, ioc);
- }
+ kref_put(&ioc->kref, release_io_context);
}
EXPORT_SYMBOL(put_io_context);
@@ -3606,7 +3606,7 @@ struct io_context *current_io_context(gf
ret = kmem_cache_alloc(iocontext_cachep, gfp_flags);
if (ret) {
- atomic_set(&ret->refcount, 1);
+ kref_init(&ret->kref);
ret->task = current;
ret->set_ioprio = NULL;
ret->last_waited = jiffies; /* doesn't matter... */
@@ -3631,7 +3631,7 @@ struct io_context *get_io_context(gfp_t
struct io_context *ret;
ret = current_io_context(gfp_flags);
if (likely(ret))
- atomic_inc(&ret->refcount);
+ kref_get(&ret->kref);
return ret;
}
EXPORT_SYMBOL(get_io_context);
@@ -3642,8 +3642,7 @@ void copy_io_context(struct io_context *
struct io_context *dst = *pdst;
if (src) {
- BUG_ON(atomic_read(&src->refcount) == 0);
- atomic_inc(&src->refcount);
+ kref_get(&src->kref);
put_io_context(dst);
*pdst = src;
}
Index: 2.6-git/include/linux/blkdev.h
===================================================================
--- 2.6-git.orig/include/linux/blkdev.h
+++ 2.6-git/include/linux/blkdev.h
@@ -88,7 +88,7 @@ struct cfq_io_context {
* (apart from the atomic refcount), so require no locking.
*/
struct io_context {
- atomic_t refcount;
+ struct kref kref;
struct task_struct *task;
int (*set_ioprio)(struct io_context *, unsigned int);
Index: 2.6-git/block/cfq-iosched.c
===================================================================
--- 2.6-git.orig/block/cfq-iosched.c
+++ 2.6-git/block/cfq-iosched.c
@@ -1068,7 +1068,7 @@ __cfq_dispatch_requests(struct cfq_data
dispatched++;
if (!cfqd->active_cic) {
- atomic_inc(&crq->io_context->ioc->refcount);
+ kref_get(&crq->io_context->ioc->kref);
cfqd->active_cic = crq->io_context;
}
--
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
