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From: Andrei Vagin <avagin@virtuozzo.com>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Subject: Re: [1/4] vmsplice: lift import_iovec() into do_vmsplice()
Date: Wed, 6 Jun 2018 15:57:52 -0700	[thread overview]
Message-ID: <20180606225751.GA1261@outlook.office365.com> (raw)
In-Reply-To: <20180528222013.18402-1-viro@ZenIV.linux.org.uk>

On Mon, May 28, 2018 at 11:20:10PM +0100, Al Viro wrote:
> From: Al Viro <viro@zeniv.linux.org.uk>
> 
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
> ---
>  fs/splice.c | 69 ++++++++++++++++++++++++++-----------------------------------
>  1 file changed, 29 insertions(+), 40 deletions(-)
> 
> diff --git a/fs/splice.c b/fs/splice.c
> index 005d09cf3fa8..920ff0b20e53 100644
> --- a/fs/splice.c
> +++ b/fs/splice.c
> @@ -1242,38 +1242,26 @@ static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
>   * For lack of a better implementation, implement vmsplice() to userspace
>   * as a simple copy of the pipes pages to the user iov.
>   */
> -static long vmsplice_to_user(struct file *file, const struct iovec __user *uiov,
> -			     unsigned long nr_segs, unsigned int flags)
> +static long vmsplice_to_user(struct file *file, struct iov_iter *iter,
> +			     unsigned int flags)
>  {
> -	struct pipe_inode_info *pipe;
> -	struct splice_desc sd;
> -	long ret;
> -	struct iovec iovstack[UIO_FASTIOV];
> -	struct iovec *iov = iovstack;
> -	struct iov_iter iter;
> +	struct pipe_inode_info *pipe = get_pipe_info(file);
> +	struct splice_desc sd = {
> +		.total_len = iov_iter_count(iter),
> +		.flags = flags,
> +		.u.data = iter
> +	};
> +	long ret = 0;
>  
> -	pipe = get_pipe_info(file);
>  	if (!pipe)
>  		return -EBADF;
>  
> -	ret = import_iovec(READ, uiov, nr_segs,
> -			   ARRAY_SIZE(iovstack), &iov, &iter);
> -	if (ret < 0)
> -		return ret;
> -
> -	sd.total_len = iov_iter_count(&iter);
> -	sd.len = 0;
> -	sd.flags = flags;
> -	sd.u.data = &iter;
> -	sd.pos = 0;
> -
>  	if (sd.total_len) {
>  		pipe_lock(pipe);
>  		ret = __splice_from_pipe(pipe, &sd, pipe_to_user);
>  		pipe_unlock(pipe);
>  	}
>  
> -	kfree(iov);
>  	return ret;
>  }
>  
> @@ -1282,14 +1270,11 @@ static long vmsplice_to_user(struct file *file, const struct iovec __user *uiov,
>   * as splice-from-memory, where the regular splice is splice-from-file (or
>   * to file). In both cases the output is a pipe, naturally.
>   */
> -static long vmsplice_to_pipe(struct file *file, const struct iovec __user *uiov,
> -			     unsigned long nr_segs, unsigned int flags)
> +static long vmsplice_to_pipe(struct file *file, struct iov_iter *iter,
> +			     unsigned int flags)
>  {
>  	struct pipe_inode_info *pipe;
> -	struct iovec iovstack[UIO_FASTIOV];
> -	struct iovec *iov = iovstack;
> -	struct iov_iter from;
> -	long ret;
> +	long ret = 0;
>  	unsigned buf_flag = 0;
>  
>  	if (flags & SPLICE_F_GIFT)
> @@ -1299,19 +1284,13 @@ static long vmsplice_to_pipe(struct file *file, const struct iovec __user *uiov,
>  	if (!pipe)
>  		return -EBADF;
>  
> -	ret = import_iovec(WRITE, uiov, nr_segs,
> -			   ARRAY_SIZE(iovstack), &iov, &from);
> -	if (ret < 0)
> -		return ret;
> -
>  	pipe_lock(pipe);
>  	ret = wait_for_space(pipe, flags);
>  	if (!ret)
> -		ret = iter_to_pipe(&from, pipe, buf_flag);
> +		ret = iter_to_pipe(iter, pipe, buf_flag);
>  	pipe_unlock(pipe);
>  	if (ret > 0)
>  		wakeup_pipe_readers(pipe);
> -	kfree(iov);
>  	return ret;
>  }
>  
> @@ -1331,29 +1310,39 @@ static long vmsplice_to_pipe(struct file *file, const struct iovec __user *uiov,
>   * Currently we punt and implement it as a normal copy, see pipe_to_user().
>   *
>   */
> -static long do_vmsplice(int fd, const struct iovec __user *iov,
> +static long do_vmsplice(int fd, const struct iovec __user *uiov,
>  			unsigned long nr_segs, unsigned int flags)
>  {
> +	struct iovec iovstack[UIO_FASTIOV];
> +	struct iovec *iov = iovstack;
> +	struct iov_iter iter;
>  	struct fd f;
>  	long error;
>  
>  	if (unlikely(flags & ~SPLICE_F_ALL))
>  		return -EINVAL;
> -	if (unlikely(nr_segs > UIO_MAXIOV))
> -		return -EINVAL;
> -	else if (unlikely(!nr_segs))
> +
> +	error = import_iovec(READ, uiov, nr_segs,
> +			   ARRAY_SIZE(iovstack), &iov, &iter);

import_iovec should be called with WRITE, if we are going to call
vmsplice_to_pipe().

> +	if (error < 0)
> +		return error;
> +
> +	if (!iov_iter_count(&iter)) {
> +		kfree(iov);
>  		return 0;
> +	}
>  
>  	error = -EBADF;
>  	f = fdget(fd);
>  	if (f.file) {
>  		if (f.file->f_mode & FMODE_WRITE)
> -			error = vmsplice_to_pipe(f.file, iov, nr_segs, flags);
> +			error = vmsplice_to_pipe(f.file, &iter, flags);
>  		else if (f.file->f_mode & FMODE_READ)
> -			error = vmsplice_to_user(f.file, iov, nr_segs, flags);
> +			error = vmsplice_to_user(f.file, &iter, flags);
>  
>  		fdput(f);
>  	}
> +	kfree(iov);
>  
>  	return error;
>  }

  parent reply	other threads:[~2018-06-06 22:58 UTC|newest]

Thread overview: 72+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-23 19:19 aio poll and a new in-kernel poll API V13 Christoph Hellwig
2018-05-23 19:19 ` [PATCH 01/33] fix io_destroy()/aio_complete() race Christoph Hellwig
2018-05-23 19:19 ` [PATCH 02/33] uapi: turn __poll_t sparse checkin on by default Christoph Hellwig
2018-05-23 19:19 ` [PATCH 03/33] fs: unexport poll_schedule_timeout Christoph Hellwig
2018-05-23 19:19 ` [PATCH 04/33] fs: cleanup do_pollfd Christoph Hellwig
2018-05-23 19:19 ` [PATCH 05/33] fs: update documentation to mention __poll_t and match the code Christoph Hellwig
2018-05-23 19:19 ` [PATCH 06/33] fs: add new vfs_poll and file_can_poll helpers Christoph Hellwig
2018-05-23 19:19 ` [PATCH 07/33] fs: introduce new ->get_poll_head and ->poll_mask methods Christoph Hellwig
2018-05-23 19:19 ` [PATCH 08/33] aio: simplify KIOCB_KEY handling Christoph Hellwig
2018-05-23 19:19 ` [PATCH 09/33] aio: simplify cancellation Christoph Hellwig
2018-05-23 19:19 ` [PATCH 10/33] aio: implement IOCB_CMD_POLL Christoph Hellwig
2018-05-23 19:20 ` [PATCH 11/33] aio: try to complete poll iocbs without context switch Christoph Hellwig
2018-05-23 19:20 ` [PATCH 12/33] net: refactor socket_poll Christoph Hellwig
2018-05-23 19:20 ` [PATCH 13/33] net: add support for ->poll_mask in proto_ops Christoph Hellwig
2018-05-23 19:20 ` [PATCH 14/33] net: remove sock_no_poll Christoph Hellwig
2018-05-23 19:20 ` [PATCH 15/33] net/tcp: convert to ->poll_mask Christoph Hellwig
2018-05-23 19:20 ` [PATCH 16/33] net/unix: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 17/33] net: convert datagram_poll users tp ->poll_mask Christoph Hellwig
2018-05-23 19:20 ` [PATCH 18/33] net/dccp: convert to ->poll_mask Christoph Hellwig
2018-05-23 19:20 ` [PATCH 19/33] net/atm: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 20/33] net/vmw_vsock: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 21/33] net/tipc: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 22/33] net/sctp: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 23/33] net/bluetooth: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 24/33] net/caif: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 25/33] net/nfc: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 26/33] net/phonet: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 27/33] net/iucv: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 28/33] net/rxrpc: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 29/33] crypto: af_alg: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 30/33] pipe: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 31/33] eventfd: switch " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 32/33] timerfd: convert " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 33/33] random: " Christoph Hellwig
2018-05-26  0:11 ` aio poll and a new in-kernel poll API V13 Al Viro
2018-05-26  7:09   ` Al Viro
2018-05-26  7:23     ` Christoph Hellwig
2018-05-27 22:27       ` Al Viro
2018-05-27 22:28         ` [PATCH 1/4] aio: all callers of aio_{read,write,fsync,poll} treat 0 and -EIOCBQUEUED the same way Al Viro
2018-05-27 22:28           ` [PATCH 2/4] aio_read_events_ring(): make a bit more readable Al Viro
2018-05-27 22:28           ` [PATCH 3/4] aio: shift copyin of iocb into io_submit_one() Al Viro
2018-05-28  5:16             ` Christoph Hellwig
2018-05-27 22:28           ` [PATCH 4/4] aio: fold do_io_submit() into callers Al Viro
2018-05-27 23:14             ` Al Viro
2018-05-28  5:24               ` Christoph Hellwig
2018-05-28  5:15           ` [PATCH 1/4] aio: all callers of aio_{read,write,fsync,poll} treat 0 and -EIOCBQUEUED the same way Christoph Hellwig
2018-05-28 14:04             ` Al Viro
2018-05-28 17:54               ` Al Viro
2018-05-28 17:57                 ` [PATCH v2 1/6] aio: take list removal to (some) callers of aio_complete() Al Viro
2018-05-28 17:57                   ` [PATCH v2 2/6] aio: all callers of aio_{read,write,fsync,poll} treat 0 and -EIOCBQUEUED the same way Al Viro
2018-05-29  6:08                     ` Christoph Hellwig
2018-05-28 17:57                   ` [PATCH v2 3/6] aio_read_events_ring(): make a bit more readable Al Viro
2018-05-28 17:57                   ` [PATCH v2 4/6] aio: shift copyin of iocb into io_submit_one() Al Viro
2018-05-28 17:57                   ` [PATCH v2 5/6] aio: fold do_io_submit() into callers Al Viro
2018-05-29  6:10                     ` Christoph Hellwig
2018-05-28 17:57                   ` [PATCH v2 6/6] aio: sanitize the limit checking in io_submit(2) Al Viro
2018-05-29  6:10                     ` Christoph Hellwig
2018-05-29  6:08                   ` [PATCH v2 1/6] aio: take list removal to (some) callers of aio_complete() Christoph Hellwig
2018-05-28 22:20                 ` [PATCH 1/4] vmsplice: lift import_iovec() into do_vmsplice() Al Viro
2018-05-28 22:20                   ` [PATCH 2/4] vmsplice(): lift importing iovec into vmsplice(2) and compat counterpart Al Viro
2018-05-28 22:20                   ` [PATCH 3/4] signalfd: lift sigmask copyin and size checks to callers of do_signalfd4() Al Viro
2018-05-28 22:20                   ` [PATCH 4/4] orangefs: simplify compat ioctl handling Al Viro
2018-05-31 11:11                     ` kbuild test robot
2018-05-31 20:54                     ` Mike Marshall
2018-05-31 21:03                       ` Al Viro
2018-06-01 21:13                         ` Mike Marshall
2018-06-06 22:57                   ` Andrei Vagin [this message]
2018-06-07 17:56                     ` [1/4] vmsplice: lift import_iovec() into do_vmsplice() Andrei Vagin
2018-06-11 20:14                       ` Cyrill Gorcunov
2018-06-11 20:16                         ` Al Viro
2018-06-11 20:18                           ` Cyrill Gorcunov
2018-06-14 22:22                           ` Andrey Vagin

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