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Subject[PATCH 07/32] aio: kiocb_cancel()
Date
Minor refactoring, to get rid of some duplicated code

v2: Fix return value for NULL kiocb, so it matches old code; change
synchronization to use xchg() instead of a bit in ki_flags, so we can
get rid of ki_flags.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
---
fs/aio.c | 79 +++++++++++++++++++++++++++++++++++-----------------------------
1 file changed, 43 insertions(+), 36 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index 0b85822..e1d4084 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -217,6 +217,29 @@ static inline void put_ioctx(struct kioctx *kioctx)
__put_ioctx(kioctx);
}

+static int kiocb_cancel(struct kioctx *ctx, struct kiocb *kiocb,
+ struct io_event *res)
+{
+ int (*cancel)(struct kiocb *, struct io_event *);
+ int ret = -EINVAL;
+
+ cancel = kiocb->ki_cancel;
+ kiocbSetCancelled(kiocb);
+ if (cancel) {
+ kiocb->ki_users++;
+ spin_unlock_irq(&ctx->ctx_lock);
+
+ memset(res, 0, sizeof(*res));
+ res->obj = (u64) kiocb->ki_obj.user;
+ res->data = kiocb->ki_user_data;
+ ret = cancel(kiocb, res);
+
+ spin_lock_irq(&ctx->ctx_lock);
+ }
+
+ return ret;
+}
+
/* ioctx_alloc
* Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
*/
@@ -287,25 +310,19 @@ out_freectx:
*/
static void kill_ctx(struct kioctx *ctx)
{
- int (*cancel)(struct kiocb *, struct io_event *);
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
struct io_event res;
+ struct kiocb *req;

spin_lock_irq(&ctx->ctx_lock);
ctx->dead = 1;
while (!list_empty(&ctx->active_reqs)) {
- struct list_head *pos = ctx->active_reqs.next;
- struct kiocb *iocb = list_kiocb(pos);
- list_del_init(&iocb->ki_list);
- cancel = iocb->ki_cancel;
- kiocbSetCancelled(iocb);
- if (cancel) {
- iocb->ki_users++;
- spin_unlock_irq(&ctx->ctx_lock);
- cancel(iocb, &res);
- spin_lock_irq(&ctx->ctx_lock);
- }
+ req = list_first_entry(&ctx->active_reqs,
+ struct kiocb, ki_list);
+
+ list_del_init(&req->ki_list);
+ kiocb_cancel(ctx, req, &res);
}

if (!ctx->reqs_active)
@@ -1409,7 +1426,7 @@ static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb,
SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
struct io_event __user *, result)
{
- int (*cancel)(struct kiocb *iocb, struct io_event *res);
+ struct io_event res;
struct kioctx *ctx;
struct kiocb *kiocb;
u32 key;
@@ -1424,32 +1441,22 @@ SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
return -EINVAL;

spin_lock_irq(&ctx->ctx_lock);
- ret = -EAGAIN;
+
kiocb = lookup_kiocb(ctx, iocb, key);
- if (kiocb && kiocb->ki_cancel) {
- cancel = kiocb->ki_cancel;
- kiocb->ki_users ++;
- kiocbSetCancelled(kiocb);
- } else
- cancel = NULL;
+ if (kiocb)
+ ret = kiocb_cancel(ctx, kiocb, &res);
+ else
+ ret = -EINVAL;
+
spin_unlock_irq(&ctx->ctx_lock);

- if (NULL != cancel) {
- struct io_event tmp;
- pr_debug("calling cancel\n");
- memset(&tmp, 0, sizeof(tmp));
- tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user;
- tmp.data = kiocb->ki_user_data;
- ret = cancel(kiocb, &tmp);
- if (!ret) {
- /* Cancellation succeeded -- copy the result
- * into the user's buffer.
- */
- if (copy_to_user(result, &tmp, sizeof(tmp)))
- ret = -EFAULT;
- }
- } else
- ret = -EINVAL;
+ if (!ret) {
+ /* Cancellation succeeded -- copy the result
+ * into the user's buffer.
+ */
+ if (copy_to_user(result, &res, sizeof(res)))
+ ret = -EFAULT;
+ }

put_ioctx(ctx);

--
1.7.12


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