Commit ae03c53d authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'work.splice' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 

Pull splice updates from Al Viro:
 "Christoph's assorted splice cleanups"

* 'work.splice' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs: rename pipe_buf ->steal to ->try_steal
  fs: make the pipe_buf_operations ->confirm operation optional
  fs: make the pipe_buf_operations ->steal operation optional
  trace: remove tracing_pipe_buf_ops
  pipe: merge anon_pipe_buf*_ops
  fs: simplify do_splice_from
  fs: simplify do_splice_to
parents 039aeb9d c928f642

drivers/char/virtio_console.c

+1 −1
Original line number Diff line number Diff line
@@ -871,7 +871,7 @@ static int pipe_to_sg(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 
		return 0;



	/* Try lock this page */

	if (pipe_buf_steal(pipe, buf) == 0) {

	if (pipe_buf_try_steal(pipe, buf)) {

		/* Get reference and unlock page for moving */

		get_page(buf->page);

		unlock_page(buf->page);

fs/fuse/dev.c

+1 −1
Original line number Diff line number Diff line
@@ -805,7 +805,7 @@ static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep) 
	if (cs->len != PAGE_SIZE)

		goto out_fallback;



	if (pipe_buf_steal(cs->pipe, buf) != 0)

	if (!pipe_buf_try_steal(cs->pipe, buf))

		goto out_fallback;



	newpage = buf->page;

fs/pipe.c

+21 −75
Original line number Diff line number Diff line
@@ -140,21 +140,20 @@ static void anon_pipe_buf_release(struct pipe_inode_info *pipe, 
		put_page(page);

}



static int anon_pipe_buf_steal(struct pipe_inode_info *pipe,

static bool anon_pipe_buf_try_steal(struct pipe_inode_info *pipe,

		struct pipe_buffer *buf)

{

	struct page *page = buf->page;



	if (page_count(page) == 1) {

	if (page_count(page) != 1)

		return false;

	memcg_kmem_uncharge_page(page, 0);

	__SetPageLocked(page);

		return 0;

	}

	return 1;

	return true;

}



/**

 * generic_pipe_buf_steal - attempt to take ownership of a &pipe_buffer

 * generic_pipe_buf_try_steal - attempt to take ownership of a &pipe_buffer

 * @pipe:	the pipe that the buffer belongs to

 * @buf:	the buffer to attempt to steal

 *
@@ -165,7 +164,7 @@ static int anon_pipe_buf_steal(struct pipe_inode_info *pipe, 
 *	he wishes; the typical use is insertion into a different file

 *	page cache.

 */

int generic_pipe_buf_steal(struct pipe_inode_info *pipe,

bool generic_pipe_buf_try_steal(struct pipe_inode_info *pipe,

		struct pipe_buffer *buf)

{

	struct page *page = buf->page;
@@ -177,12 +176,11 @@ int generic_pipe_buf_steal(struct pipe_inode_info *pipe, 
	 */

	if (page_count(page) == 1) {

		lock_page(page);

		return 0;

		return true;

	}



	return 1;

	return false;

}

EXPORT_SYMBOL(generic_pipe_buf_steal);

EXPORT_SYMBOL(generic_pipe_buf_try_steal);



/**

 * generic_pipe_buf_get - get a reference to a &struct pipe_buffer
@@ -200,22 +198,6 @@ bool generic_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf) 
}

EXPORT_SYMBOL(generic_pipe_buf_get);



/**

 * generic_pipe_buf_confirm - verify contents of the pipe buffer

 * @info:	the pipe that the buffer belongs to

 * @buf:	the buffer to confirm

 *

 * Description:

 *	This function does nothing, because the generic pipe code uses

 *	pages that are always good when inserted into the pipe.

 */

int generic_pipe_buf_confirm(struct pipe_inode_info *info,

			     struct pipe_buffer *buf)

{

	return 0;

}

EXPORT_SYMBOL(generic_pipe_buf_confirm);



/**

 * generic_pipe_buf_release - put a reference to a &struct pipe_buffer

 * @pipe:	the pipe that the buffer belongs to
@@ -231,48 +213,12 @@ void generic_pipe_buf_release(struct pipe_inode_info *pipe, 
}

EXPORT_SYMBOL(generic_pipe_buf_release);



/* New data written to a pipe may be appended to a buffer with this type. */

static const struct pipe_buf_operations anon_pipe_buf_ops = {

	.confirm = generic_pipe_buf_confirm,

	.release = anon_pipe_buf_release,

	.steal = anon_pipe_buf_steal,

	.get = generic_pipe_buf_get,

};



static const struct pipe_buf_operations anon_pipe_buf_nomerge_ops = {

	.confirm = generic_pipe_buf_confirm,

	.release = anon_pipe_buf_release,

	.steal = anon_pipe_buf_steal,

	.get = generic_pipe_buf_get,

};



static const struct pipe_buf_operations packet_pipe_buf_ops = {

	.confirm = generic_pipe_buf_confirm,

	.release	= anon_pipe_buf_release,

	.steal = anon_pipe_buf_steal,

	.try_steal	= anon_pipe_buf_try_steal,

	.get		= generic_pipe_buf_get,

};



/**

 * pipe_buf_mark_unmergeable - mark a &struct pipe_buffer as unmergeable

 * @buf:	the buffer to mark

 *

 * Description:

 *	This function ensures that no future writes will be merged into the

 *	given &struct pipe_buffer. This is necessary when multiple pipe buffers

 *	share the same backing page.

 */

void pipe_buf_mark_unmergeable(struct pipe_buffer *buf)

{

	if (buf->ops == &anon_pipe_buf_ops)

		buf->ops = &anon_pipe_buf_nomerge_ops;

}



static bool pipe_buf_can_merge(struct pipe_buffer *buf)

{

	return buf->ops == &anon_pipe_buf_ops;

}



/* Done while waiting without holding the pipe lock - thus the READ_ONCE() */

static inline bool pipe_readable(const struct pipe_inode_info *pipe)

{
@@ -478,7 +424,8 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from) 
		struct pipe_buffer *buf = &pipe->bufs[(head - 1) & mask];

		int offset = buf->offset + buf->len;



		if (pipe_buf_can_merge(buf) && offset + chars <= PAGE_SIZE) {

		if ((buf->flags & PIPE_BUF_FLAG_CAN_MERGE) &&

		    offset + chars <= PAGE_SIZE) {

			ret = pipe_buf_confirm(pipe, buf);

			if (ret)

				goto out;
@@ -541,11 +488,10 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from) 
			buf->ops = &anon_pipe_buf_ops;

			buf->offset = 0;

			buf->len = 0;

			buf->flags = 0;

			if (is_packetized(filp)) {

				buf->ops = &packet_pipe_buf_ops;

			if (is_packetized(filp))

				buf->flags = PIPE_BUF_FLAG_PACKET;

			}

			else

				buf->flags = PIPE_BUF_FLAG_CAN_MERGE;

			pipe->tmp_page = NULL;



			copied = copy_page_from_iter(page, 0, PAGE_SIZE, from);

fs/splice.c

+29 −52
Original line number Diff line number Diff line
@@ -44,7 +44,7 @@ 
 * addition of remove_mapping(). If success is returned, the caller may

 * attempt to reuse this page for another destination.

 */

static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe,

static bool page_cache_pipe_buf_try_steal(struct pipe_inode_info *pipe,

		struct pipe_buffer *buf)

{

	struct page *page = buf->page;
@@ -76,7 +76,7 @@ static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe, 
		 */

		if (remove_mapping(mapping, page)) {

			buf->flags |= PIPE_BUF_FLAG_LRU;

			return 0;

			return true;

		}

	}
@@ -86,7 +86,7 @@ static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe, 
	 */

out_unlock:

	unlock_page(page);

	return 1;

	return false;

}



static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe,
@@ -141,24 +141,23 @@ error: 
const struct pipe_buf_operations page_cache_pipe_buf_ops = {

	.confirm	= page_cache_pipe_buf_confirm,

	.release	= page_cache_pipe_buf_release,

	.steal = page_cache_pipe_buf_steal,

	.try_steal	= page_cache_pipe_buf_try_steal,

	.get		= generic_pipe_buf_get,

};



static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe,

static bool user_page_pipe_buf_try_steal(struct pipe_inode_info *pipe,

		struct pipe_buffer *buf)

{

	if (!(buf->flags & PIPE_BUF_FLAG_GIFT))

		return 1;

		return false;



	buf->flags |= PIPE_BUF_FLAG_LRU;

	return generic_pipe_buf_steal(pipe, buf);

	return generic_pipe_buf_try_steal(pipe, buf);

}



static const struct pipe_buf_operations user_page_pipe_buf_ops = {

	.confirm = generic_pipe_buf_confirm,

	.release	= page_cache_pipe_buf_release,

	.steal = user_page_pipe_buf_steal,

	.try_steal	= user_page_pipe_buf_try_steal,

	.get		= generic_pipe_buf_get,

};
@@ -331,23 +330,14 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 
EXPORT_SYMBOL(generic_file_splice_read);



const struct pipe_buf_operations default_pipe_buf_ops = {

	.confirm = generic_pipe_buf_confirm,

	.release	= generic_pipe_buf_release,

	.steal = generic_pipe_buf_steal,

	.try_steal	= generic_pipe_buf_try_steal,

	.get		= generic_pipe_buf_get,

};



int generic_pipe_buf_nosteal(struct pipe_inode_info *pipe,

			     struct pipe_buffer *buf)

{

	return 1;

}



/* Pipe buffer operations for a socket and similar. */

const struct pipe_buf_operations nosteal_pipe_buf_ops = {

	.confirm = generic_pipe_buf_confirm,

	.release	= generic_pipe_buf_release,

	.steal = generic_pipe_buf_nosteal,

	.get		= generic_pipe_buf_get,

};

EXPORT_SYMBOL(nosteal_pipe_buf_ops);
@@ -852,15 +842,9 @@ EXPORT_SYMBOL(generic_splice_sendpage); 
static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,

			   loff_t *ppos, size_t len, unsigned int flags)

{

	ssize_t (*splice_write)(struct pipe_inode_info *, struct file *,

				loff_t *, size_t, unsigned int);



	if (out->f_op->splice_write)

		splice_write = out->f_op->splice_write;

	else

		splice_write = default_file_splice_write;



	return splice_write(pipe, out, ppos, len, flags);

		return out->f_op->splice_write(pipe, out, ppos, len, flags);

	return default_file_splice_write(pipe, out, ppos, len, flags);

}



/*
@@ -870,8 +854,6 @@ static long do_splice_to(struct file *in, loff_t *ppos, 
			 struct pipe_inode_info *pipe, size_t len,

			 unsigned int flags)

{

	ssize_t (*splice_read)(struct file *, loff_t *,

			       struct pipe_inode_info *, size_t, unsigned int);

	int ret;



	if (unlikely(!(in->f_mode & FMODE_READ)))
@@ -885,11 +867,8 @@ static long do_splice_to(struct file *in, loff_t *ppos, 
		len = MAX_RW_COUNT;



	if (in->f_op->splice_read)

		splice_read = in->f_op->splice_read;

	else

		splice_read = default_file_splice_read;



	return splice_read(in, ppos, pipe, len, flags);

		return in->f_op->splice_read(in, ppos, pipe, len, flags);

	return default_file_splice_read(in, ppos, pipe, len, flags);

}



/**
@@ -1626,12 +1605,11 @@ retry: 
			*obuf = *ibuf;



			/*

			 * Don't inherit the gift flag, we need to

			 * Don't inherit the gift and merge flags, we need to

			 * prevent multiple steals of this page.

			 */

			obuf->flags &= ~PIPE_BUF_FLAG_GIFT;



			pipe_buf_mark_unmergeable(obuf);

			obuf->flags &= ~PIPE_BUF_FLAG_CAN_MERGE;



			obuf->len = len;

			ibuf->offset += len;
@@ -1719,12 +1697,11 @@ static int link_pipe(struct pipe_inode_info *ipipe, 
		*obuf = *ibuf;



		/*

		 * Don't inherit the gift flag, we need to

		 * prevent multiple steals of this page.

		 * Don't inherit the gift and merge flag, we need to prevent

		 * multiple steals of this page.

		 */

		obuf->flags &= ~PIPE_BUF_FLAG_GIFT;



		pipe_buf_mark_unmergeable(obuf);

		obuf->flags &= ~PIPE_BUF_FLAG_CAN_MERGE;



		if (obuf->len > len)

			obuf->len = len;

include/linux/pipe_fs_i.h

+21 −19
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
#define PIPE_BUF_FLAG_ATOMIC	0x02	/* was atomically mapped */

#define PIPE_BUF_FLAG_GIFT	0x04	/* page is a gift */

#define PIPE_BUF_FLAG_PACKET	0x08	/* read() as a packet */

#define PIPE_BUF_FLAG_CAN_MERGE	0x10	/* can merge buffers */



/**

 *	struct pipe_buffer - a linux kernel pipe buffer
@@ -69,11 +70,11 @@ struct pipe_inode_info { 
 * Note on the nesting of these functions:

 *

 * ->confirm()

 *	->steal()

 *	->try_steal()

 *

 * That is, ->steal() must be called on a confirmed buffer.

 * See below for the meaning of each operation. Also see kerneldoc

 * in fs/pipe.c for the pipe and generic variants of these hooks.

 * That is, ->try_steal() must be called on a confirmed buffer.  See below for

 * the meaning of each operation.  Also see the kerneldoc in fs/pipe.c for the

 * pipe and generic variants of these hooks.

 */

struct pipe_buf_operations {

	/*
@@ -81,7 +82,7 @@ struct pipe_buf_operations { 
	 * and that the contents are good. If the pages in the pipe belong

	 * to a file system, we may need to wait for IO completion in this

	 * hook. Returns 0 for good, or a negative error value in case of

	 * error.

	 * error.  If not present all pages are considered good.

	 */

	int (*confirm)(struct pipe_inode_info *, struct pipe_buffer *);
@@ -93,13 +94,13 @@ struct pipe_buf_operations { 


	/*

	 * Attempt to take ownership of the pipe buffer and its contents.

	 * ->steal() returns 0 for success, in which case the contents

	 * of the pipe (the buf->page) is locked and now completely owned

	 * by the caller. The page may then be transferred to a different

	 * mapping, the most often used case is insertion into different

	 * file address space cache.

	 * ->try_steal() returns %true for success, in which case the contents

	 * of the pipe (the buf->page) is locked and now completely owned by the

	 * caller. The page may then be transferred to a different mapping, the

	 * most often used case is insertion into different file address space

	 * cache.

	 */

	int (*steal)(struct pipe_inode_info *, struct pipe_buffer *);

	bool (*try_steal)(struct pipe_inode_info *, struct pipe_buffer *);



	/*

	 * Get a reference to the pipe buffer.
@@ -194,18 +195,22 @@ static inline void pipe_buf_release(struct pipe_inode_info *pipe, 
static inline int pipe_buf_confirm(struct pipe_inode_info *pipe,

				   struct pipe_buffer *buf)

{

	if (!buf->ops->confirm)

		return 0;

	return buf->ops->confirm(pipe, buf);

}



/**

 * pipe_buf_steal - attempt to take ownership of a pipe_buffer

 * pipe_buf_try_steal - attempt to take ownership of a pipe_buffer

 * @pipe:	the pipe that the buffer belongs to

 * @buf:	the buffer to attempt to steal

 */

static inline int pipe_buf_steal(struct pipe_inode_info *pipe,

static inline bool pipe_buf_try_steal(struct pipe_inode_info *pipe,

		struct pipe_buffer *buf)

{

	return buf->ops->steal(pipe, buf);

	if (!buf->ops->try_steal)

		return false;

	return buf->ops->try_steal(pipe, buf);

}



/* Differs from PIPE_BUF in that PIPE_SIZE is the length of the actual
@@ -229,11 +234,8 @@ void free_pipe_info(struct pipe_inode_info *); 


/* Generic pipe buffer ops functions */

bool generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *);

int generic_pipe_buf_confirm(struct pipe_inode_info *, struct pipe_buffer *);

int generic_pipe_buf_steal(struct pipe_inode_info *, struct pipe_buffer *);

int generic_pipe_buf_nosteal(struct pipe_inode_info *, struct pipe_buffer *);

bool generic_pipe_buf_try_steal(struct pipe_inode_info *, struct pipe_buffer *);

void generic_pipe_buf_release(struct pipe_inode_info *, struct pipe_buffer *);

void pipe_buf_mark_unmergeable(struct pipe_buffer *buf);



extern const struct pipe_buf_operations nosteal_pipe_buf_ops;

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