On Thu, May 22, 2008 at 10:27:30PM +0100, Alan Cox wrote:
> One or two bits I couldn't figure out if the BKL could be dropped for
>
> Signed-off-by: Alan Cox <alan@xxxxxxxxxx>
Ack to the net/sunrpc/cache.c change.
The net/sunrpc/rpc_pipe.c changes look fine too, except that there's no
point keeping the BKL anywhere there.
As a matter of fact I think that rpc_pipe_ioctl *is* racy, but that's a
preexisting problem--it needs the i_lock or i_mutex, not the BKL.
(I'm not sure how important the rpci->ops check is, but the "len"
calculation would make more sense if it were atomic, and couldn't the
separate check and dereference of filp->private data lead to a null
deference?)
--b.
>
> diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
> index c996671..0c1af5d 100644
> --- a/net/sunrpc/cache.c
> +++ b/net/sunrpc/cache.c
> @@ -826,11 +826,11 @@ cache_poll(struct file *filp, poll_table *wait)
> return mask;
> }
>
> -static int
> -cache_ioctl(struct inode *ino, struct file *filp,
> - unsigned int cmd, unsigned long arg)
> +static long
> +cache_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> {
> int len = 0;
> + struct inode *ino = filp->f_path.dentry->d_inode;
> struct cache_reader *rp = filp->private_data;
> struct cache_queue *cq;
> struct cache_detail *cd = PDE(ino)->data;
> @@ -918,7 +918,7 @@ static const struct file_operations cache_file_operations = {
> .read = cache_read,
> .write = cache_write,
> .poll = cache_poll,
> - .ioctl = cache_ioctl, /* for FIONREAD */
> + .unlocked_ioctl = cache_ioctl, /* for FIONREAD */
> .open = cache_open,
> .release = cache_release,
> };
> diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
> index 5a9b0e7..80bca08 100644
> --- a/net/sunrpc/rpc_pipe.c
> +++ b/net/sunrpc/rpc_pipe.c
> @@ -296,23 +296,26 @@ rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
> return mask;
> }
>
> -static int
> -rpc_pipe_ioctl(struct inode *ino, struct file *filp,
> - unsigned int cmd, unsigned long arg)
> +static long
> +rpc_pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> {
> struct rpc_inode *rpci = RPC_I(filp->f_path.dentry->d_inode);
> int len;
>
> switch (cmd) {
> case FIONREAD:
> - if (rpci->ops == NULL)
> + lock_kernel();
> + if (rpci->ops == NULL) {
> + unlock_kernel();
> return -EPIPE;
> + }
> len = rpci->pipelen;
> if (filp->private_data) {
> struct rpc_pipe_msg *msg;
> msg = (struct rpc_pipe_msg *)filp->private_data;
> len += msg->len - msg->copied;
> }
> + unlock_kernel();
> return put_user(len, (int __user *)arg);
> default:
> return -EINVAL;
> @@ -325,7 +328,7 @@ static const struct file_operations rpc_pipe_fops = {
> .read = rpc_pipe_read,
> .write = rpc_pipe_write,
> .poll = rpc_pipe_poll,
> - .ioctl = rpc_pipe_ioctl,
> + .unlocked_ioctl = rpc_pipe_ioctl,
> .open = rpc_pipe_open,
> .release = rpc_pipe_release,
> };
> --
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