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    Subject[PATCH 07/26] 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 | 72 +++++++++++++++++++++++++++++++++++-----------------------------
    1 file changed, 39 insertions(+), 33 deletions(-)

    diff --git a/fs/aio.c b/fs/aio.c
    index 91879d4..786c904 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.
    */
    @@ -287,7 +310,6 @@ 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;
    @@ -298,14 +320,8 @@ static void kill_ctx(struct kioctx *ctx)
    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);
    - }
    +
    + kiocb_cancel(ctx, iocb, &res);
    }

    if (!ctx->reqs_active)
    @@ -1411,7 +1427,7 @@ 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;
    @@ -1426,32 +1442,22 @@ 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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