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fs: rename pipe_buf ->steal to ->try_steal

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And replace the arcane return value convention with a simple bool
where true means success and false means failure.

[AV: braino fix folded in]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Christoph Hellwig 2020-05-20 17:58:16 +02:00 committed by Al Viro
parent b8d9e7f241
commit c928f642c2
6 changed files with 58 additions and 60 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/char/virtio_console.c
View File

@ -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);

2
fs/fuse/dev.c
View File

@ -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;

34
fs/pipe.c
View File

@ -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,
struct pipe_buffer *buf)
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) {
memcg_kmem_uncharge_page(page, 0);
__SetPageLocked(page);
return 0;
}
return 1;
if (page_count(page) != 1)
return false;
memcg_kmem_uncharge_page(page, 0);
__SetPageLocked(page);
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
*
@ -165,8 +164,8 @@ 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,
struct pipe_buffer *buf)
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
@ -216,9 +214,9 @@ void generic_pipe_buf_release(struct pipe_inode_info *pipe,
EXPORT_SYMBOL(generic_pipe_buf_release);
static const struct pipe_buf_operations anon_pipe_buf_ops = {
.release = anon_pipe_buf_release,
.steal = anon_pipe_buf_steal,
.get = generic_pipe_buf_get,
.release = anon_pipe_buf_release,
.try_steal = anon_pipe_buf_try_steal,
.get = generic_pipe_buf_get,
};
/* Done while waiting without holding the pipe lock - thus the READ_ONCE() */

40
fs/splice.c
View File

@ -44,8 +44,8 @@
* 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,
struct pipe_buffer *buf)
static bool page_cache_pipe_buf_try_steal(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
struct page *page = buf->page;
struct address_space *mapping;
@ -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,
@ -139,26 +139,26 @@ 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,
.get = generic_pipe_buf_get,
.confirm = page_cache_pipe_buf_confirm,
.release = page_cache_pipe_buf_release,
.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,
struct pipe_buffer *buf)
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 = {
.release = page_cache_pipe_buf_release,
.steal = user_page_pipe_buf_steal,
.get = generic_pipe_buf_get,
.release = page_cache_pipe_buf_release,
.try_steal = user_page_pipe_buf_try_steal,
.get = generic_pipe_buf_get,
};
static void wakeup_pipe_readers(struct pipe_inode_info *pipe)
@ -330,15 +330,15 @@ 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 = {
.release = generic_pipe_buf_release,
.steal = generic_pipe_buf_steal,
.get = generic_pipe_buf_get,
.release = generic_pipe_buf_release,
.try_steal = generic_pipe_buf_try_steal,
.get = generic_pipe_buf_get,
};
/* Pipe buffer operations for a socket and similar. */
const struct pipe_buf_operations nosteal_pipe_buf_ops = {
.release = generic_pipe_buf_release,
.get = generic_pipe_buf_get,
.release = generic_pipe_buf_release,
.get = generic_pipe_buf_get,
};
EXPORT_SYMBOL(nosteal_pipe_buf_ops);

34
include/linux/pipe_fs_i.h
View File

@ -70,11 +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 {
/*
@ -94,13 +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.
@ -201,16 +201,16 @@ static inline int pipe_buf_confirm(struct pipe_inode_info *pipe,
}
/**
* 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,
struct pipe_buffer *buf)
static inline bool pipe_buf_try_steal(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
if (!buf->ops->steal)
return 1;
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
@ -234,7 +234,7 @@ 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_steal(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 *);
extern const struct pipe_buf_operations nosteal_pipe_buf_ops;

6
kernel/relay.c
View File

@ -1177,9 +1177,9 @@ static void relay_pipe_buf_release(struct pipe_inode_info *pipe,
}
static const struct pipe_buf_operations relay_pipe_buf_ops = {
.release = relay_pipe_buf_release,
.steal = generic_pipe_buf_steal,
.get = generic_pipe_buf_get,
.release = relay_pipe_buf_release,
.try_steal = generic_pipe_buf_try_steal,
.get = generic_pipe_buf_get,
};
static void relay_page_release(struct splice_pipe_desc *spd, unsigned int i)