block: Fix io_context leak after failure of clone with CLONE_IO

With CLONE_IO, parent's io_context->nr_tasks is incremented, but never
decremented whenever copy_process() fails afterwards, which prevents
exit_io_context() from calling IO schedulers exit functions.

Give a task_struct to exit_io_context(), and call exit_io_context() instead of
put_io_context() in copy_process() cleanup path.

Signed-off-by: Louis Rilling <louis.rilling@kerlabs.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Louis Rilling 2009-12-04 14:52:42 +01:00 committed by Jens Axboe
parent 61cc74fbb8
commit b69f229206
4 changed files with 11 additions and 9 deletions

View File

@ -66,14 +66,14 @@ static void cfq_exit(struct io_context *ioc)
}
/* Called by the exitting task */
void exit_io_context(void)
void exit_io_context(struct task_struct *task)
{
struct io_context *ioc;
task_lock(current);
ioc = current->io_context;
current->io_context = NULL;
task_unlock(current);
task_lock(task);
ioc = task->io_context;
task->io_context = NULL;
task_unlock(task);
if (atomic_dec_and_test(&ioc->nr_tasks)) {
if (ioc->aic && ioc->aic->exit)

View File

@ -98,14 +98,15 @@ static inline struct io_context *ioc_task_link(struct io_context *ioc)
return NULL;
}
struct task_struct;
#ifdef CONFIG_BLOCK
int put_io_context(struct io_context *ioc);
void exit_io_context(void);
void exit_io_context(struct task_struct *task);
struct io_context *get_io_context(gfp_t gfp_flags, int node);
struct io_context *alloc_io_context(gfp_t gfp_flags, int node);
void copy_io_context(struct io_context **pdst, struct io_context **psrc);
#else
static inline void exit_io_context(void)
static inline void exit_io_context(struct task_struct *task)
{
}

View File

@ -1004,7 +1004,7 @@ NORET_TYPE void do_exit(long code)
tsk->flags |= PF_EXITPIDONE;
if (tsk->io_context)
exit_io_context();
exit_io_context(tsk);
if (tsk->splice_pipe)
__free_pipe_info(tsk->splice_pipe);

View File

@ -1310,7 +1310,8 @@ static struct task_struct *copy_process(unsigned long clone_flags,
if (pid != &init_struct_pid)
free_pid(pid);
bad_fork_cleanup_io:
put_io_context(p->io_context);
if (p->io_context)
exit_io_context(p);
bad_fork_cleanup_namespaces:
exit_task_namespaces(p);
bad_fork_cleanup_mm: