[PATCH RT 31/36] fs/aio: simple simple work

Steven Rostedt
2015-03-12T19:26:15Z

[-- Attachment #1: 0031-fs-aio-simple-simple-work.patch --]
[-- Type: text/plain, Size: 3751 bytes --]

3.12.38-rt53-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

|BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:768
|in_atomic(): 1, irqs_disabled(): 0, pid: 26, name: rcuos/2
|2 locks held by rcuos/2/26:
| #0: (rcu_callback){.+.+..}, at: [<ffffffff810b1a12>] rcu_nocb_kthread+0x1e2/0x380
| #1: (rcu_read_lock_sched){.+.+..}, at: [<ffffffff812acd26>] percpu_ref_kill_rcu+0xa6/0x1c0
|Preemption disabled at:[<ffffffff810b1a93>] rcu_nocb_kthread+0x263/0x380
|Call Trace:
| [<ffffffff81582e9e>] dump_stack+0x4e/0x9c
| [<ffffffff81077aeb>] __might_sleep+0xfb/0x170
| [<ffffffff81589304>] rt_spin_lock+0x24/0x70
| [<ffffffff811c5790>] free_ioctx_users+0x30/0x130
| [<ffffffff812ace34>] percpu_ref_kill_rcu+0x1b4/0x1c0
| [<ffffffff810b1a93>] rcu_nocb_kthread+0x263/0x380
| [<ffffffff8106e046>] kthread+0xd6/0xf0
| [<ffffffff81591eec>] ret_from_fork+0x7c/0xb0

replace this preempt_disable() friendly swork.

Cc: stable-rt@vger.kernel.org
Reported-By: Mike Galbraith <umgwanakikbuti@gmail.com>
Suggested-by: Benjamin LaHaise <bcrl@kvack.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
fs/aio.c | 24 +++++++++++++++++-------
1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index 307d7708dc00..6fadd7a282da 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -40,6 +40,7 @@
#include <linux/ramfs.h>
#include <linux/percpu-refcount.h>
#include <linux/mount.h>
+#include <linux/work-simple.h>

#include <asm/kmap_types.h>
#include <asm/uaccess.h>
@@ -110,7 +111,7 @@ struct kioctx {
struct page **ring_pages;
long nr_pages;

- struct work_struct free_work;
+ struct swork_event free_work;

/*
* signals when all in-flight requests are done
@@ -226,6 +227,7 @@ static int __init aio_setup(void)
.mount = aio_mount,
.kill_sb = kill_anon_super,
};
+ BUG_ON(swork_get());
aio_mnt = kern_mount(&aio_fs);
if (IS_ERR(aio_mnt))
panic("Failed to create aio fs mount.");
@@ -505,9 +507,9 @@ static int kiocb_cancel(struct kioctx *ctx, struct kiocb *kiocb)
return cancel(kiocb);
}

-static void free_ioctx(struct work_struct *work)
+static void free_ioctx(struct swork_event *sev)
{
- struct kioctx *ctx = container_of(work, struct kioctx, free_work);
+ struct kioctx *ctx = container_of(sev, struct kioctx, free_work);

pr_debug("freeing %p\n", ctx);

@@ -524,8 +526,8 @@ static void free_ioctx_reqs(struct percpu_ref *ref)
if (ctx->requests_done)
complete(ctx->requests_done);

- INIT_WORK(&ctx->free_work, free_ioctx);
- schedule_work(&ctx->free_work);
+ INIT_SWORK(&ctx->free_work, free_ioctx);
+ swork_queue(&ctx->free_work);
}

/*
@@ -533,9 +535,9 @@ static void free_ioctx_reqs(struct percpu_ref *ref)
* and ctx->users has dropped to 0, so we know no more kiocbs can be submitted -
* now it's safe to cancel any that need to be.
*/
-static void free_ioctx_users(struct percpu_ref *ref)
+static void free_ioctx_users_work(struct swork_event *sev)
{
- struct kioctx *ctx = container_of(ref, struct kioctx, users);
+ struct kioctx *ctx = container_of(sev, struct kioctx, free_work);
struct kiocb *req;

spin_lock_irq(&ctx->ctx_lock);
@@ -554,6 +556,14 @@ static void free_ioctx_users(struct percpu_ref *ref)
percpu_ref_put(&ctx->reqs);
}

+static void free_ioctx_users(struct percpu_ref *ref)
+{
+ struct kioctx *ctx = container_of(ref, struct kioctx, users);
+
+ INIT_SWORK(&ctx->free_work, free_ioctx_users_work);
+ swork_queue(&ctx->free_work);
+}
+
static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
{
unsigned i, new_nr;
--
2.1.4