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
This commit is contained in:
Linus Torvalds 2020-06-03 15:52:19 -07:00
commit ae03c53d00
8 changed files with 77 additions and 170 deletions

View File

@ -871,7 +871,7 @@ static int pipe_to_sg(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
return 0; return 0;
/* Try lock this page */ /* 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 reference and unlock page for moving */
get_page(buf->page); get_page(buf->page);
unlock_page(buf->page); unlock_page(buf->page);

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) if (cs->len != PAGE_SIZE)
goto out_fallback; goto out_fallback;
if (pipe_buf_steal(cs->pipe, buf) != 0) if (!pipe_buf_try_steal(cs->pipe, buf))
goto out_fallback; goto out_fallback;
newpage = buf->page; newpage = buf->page;

View File

@ -140,21 +140,20 @@ static void anon_pipe_buf_release(struct pipe_inode_info *pipe,
put_page(page); 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 pipe_buffer *buf)
{ {
struct page *page = buf->page; struct page *page = buf->page;
if (page_count(page) == 1) { if (page_count(page) != 1)
memcg_kmem_uncharge_page(page, 0); return false;
__SetPageLocked(page); memcg_kmem_uncharge_page(page, 0);
return 0; __SetPageLocked(page);
} return true;
return 1;
} }
/** /**
* 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 * @pipe: the pipe that the buffer belongs to
* @buf: the buffer to attempt to steal * @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 * he wishes; the typical use is insertion into a different file
* page cache. * 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 pipe_buffer *buf)
{ {
struct page *page = buf->page; struct page *page = buf->page;
@ -177,12 +176,11 @@ int generic_pipe_buf_steal(struct pipe_inode_info *pipe,
*/ */
if (page_count(page) == 1) { if (page_count(page) == 1) {
lock_page(page); lock_page(page);
return 0; return true;
} }
return false;
return 1;
} }
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 * 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); 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 * generic_pipe_buf_release - put a reference to a &struct pipe_buffer
* @pipe: the pipe that the buffer belongs to * @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); 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 = { static const struct pipe_buf_operations anon_pipe_buf_ops = {
.confirm = generic_pipe_buf_confirm, .release = anon_pipe_buf_release,
.release = anon_pipe_buf_release, .try_steal = anon_pipe_buf_try_steal,
.steal = anon_pipe_buf_steal, .get = generic_pipe_buf_get,
.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,
.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() */ /* Done while waiting without holding the pipe lock - thus the READ_ONCE() */
static inline bool pipe_readable(const struct pipe_inode_info *pipe) 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]; struct pipe_buffer *buf = &pipe->bufs[(head - 1) & mask];
int offset = buf->offset + buf->len; 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); ret = pipe_buf_confirm(pipe, buf);
if (ret) if (ret)
goto out; goto out;
@ -541,11 +488,10 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
buf->ops = &anon_pipe_buf_ops; buf->ops = &anon_pipe_buf_ops;
buf->offset = 0; buf->offset = 0;
buf->len = 0; buf->len = 0;
buf->flags = 0; if (is_packetized(filp))
if (is_packetized(filp)) {
buf->ops = &packet_pipe_buf_ops;
buf->flags = PIPE_BUF_FLAG_PACKET; buf->flags = PIPE_BUF_FLAG_PACKET;
} else
buf->flags = PIPE_BUF_FLAG_CAN_MERGE;
pipe->tmp_page = NULL; pipe->tmp_page = NULL;
copied = copy_page_from_iter(page, 0, PAGE_SIZE, from); copied = copy_page_from_iter(page, 0, PAGE_SIZE, from);

View File

@ -44,8 +44,8 @@
* addition of remove_mapping(). If success is returned, the caller may * addition of remove_mapping(). If success is returned, the caller may
* attempt to reuse this page for another destination. * 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 pipe_buffer *buf)
{ {
struct page *page = buf->page; struct page *page = buf->page;
struct address_space *mapping; 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)) { if (remove_mapping(mapping, page)) {
buf->flags |= PIPE_BUF_FLAG_LRU; 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: out_unlock:
unlock_page(page); unlock_page(page);
return 1; return false;
} }
static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe, static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe,
@ -139,27 +139,26 @@ static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe,
} }
const struct pipe_buf_operations page_cache_pipe_buf_ops = { const struct pipe_buf_operations page_cache_pipe_buf_ops = {
.confirm = page_cache_pipe_buf_confirm, .confirm = page_cache_pipe_buf_confirm,
.release = page_cache_pipe_buf_release, .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, .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) struct pipe_buffer *buf)
{ {
if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) if (!(buf->flags & PIPE_BUF_FLAG_GIFT))
return 1; return false;
buf->flags |= PIPE_BUF_FLAG_LRU; 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 = { static const struct pipe_buf_operations user_page_pipe_buf_ops = {
.confirm = generic_pipe_buf_confirm, .release = page_cache_pipe_buf_release,
.release = page_cache_pipe_buf_release, .try_steal = user_page_pipe_buf_try_steal,
.steal = user_page_pipe_buf_steal, .get = generic_pipe_buf_get,
.get = generic_pipe_buf_get,
}; };
static void wakeup_pipe_readers(struct pipe_inode_info *pipe) static void wakeup_pipe_readers(struct pipe_inode_info *pipe)
@ -331,24 +330,15 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
EXPORT_SYMBOL(generic_file_splice_read); EXPORT_SYMBOL(generic_file_splice_read);
const struct pipe_buf_operations default_pipe_buf_ops = { const struct pipe_buf_operations default_pipe_buf_ops = {
.confirm = generic_pipe_buf_confirm, .release = generic_pipe_buf_release,
.release = generic_pipe_buf_release, .try_steal = generic_pipe_buf_try_steal,
.steal = generic_pipe_buf_steal, .get = generic_pipe_buf_get,
.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. */ /* Pipe buffer operations for a socket and similar. */
const struct pipe_buf_operations nosteal_pipe_buf_ops = { const struct pipe_buf_operations nosteal_pipe_buf_ops = {
.confirm = generic_pipe_buf_confirm, .release = generic_pipe_buf_release,
.release = generic_pipe_buf_release, .get = generic_pipe_buf_get,
.steal = generic_pipe_buf_nosteal,
.get = generic_pipe_buf_get,
}; };
EXPORT_SYMBOL(nosteal_pipe_buf_ops); 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, static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
loff_t *ppos, size_t len, unsigned int flags) 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) if (out->f_op->splice_write)
splice_write = out->f_op->splice_write; return out->f_op->splice_write(pipe, out, ppos, len, flags);
else return default_file_splice_write(pipe, out, ppos, len, flags);
splice_write = default_file_splice_write;
return 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, struct pipe_inode_info *pipe, size_t len,
unsigned int flags) unsigned int flags)
{ {
ssize_t (*splice_read)(struct file *, loff_t *,
struct pipe_inode_info *, size_t, unsigned int);
int ret; int ret;
if (unlikely(!(in->f_mode & FMODE_READ))) 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; len = MAX_RW_COUNT;
if (in->f_op->splice_read) if (in->f_op->splice_read)
splice_read = in->f_op->splice_read; return in->f_op->splice_read(in, ppos, pipe, len, flags);
else return default_file_splice_read(in, ppos, pipe, len, flags);
splice_read = default_file_splice_read;
return splice_read(in, ppos, pipe, len, flags);
} }
/** /**
@ -1626,12 +1605,11 @@ static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe,
*obuf = *ibuf; *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. * prevent multiple steals of this page.
*/ */
obuf->flags &= ~PIPE_BUF_FLAG_GIFT; obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
obuf->flags &= ~PIPE_BUF_FLAG_CAN_MERGE;
pipe_buf_mark_unmergeable(obuf);
obuf->len = len; obuf->len = len;
ibuf->offset += len; ibuf->offset += len;
@ -1719,12 +1697,11 @@ static int link_pipe(struct pipe_inode_info *ipipe,
*obuf = *ibuf; *obuf = *ibuf;
/* /*
* Don't inherit the gift flag, we need to * Don't inherit the gift and merge flag, we need to prevent
* prevent multiple steals of this page. * multiple steals of this page.
*/ */
obuf->flags &= ~PIPE_BUF_FLAG_GIFT; obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
obuf->flags &= ~PIPE_BUF_FLAG_CAN_MERGE;
pipe_buf_mark_unmergeable(obuf);
if (obuf->len > len) if (obuf->len > len)
obuf->len = len; obuf->len = len;

View File

@ -8,6 +8,7 @@
#define PIPE_BUF_FLAG_ATOMIC 0x02 /* was atomically mapped */ #define PIPE_BUF_FLAG_ATOMIC 0x02 /* was atomically mapped */
#define PIPE_BUF_FLAG_GIFT 0x04 /* page is a gift */ #define PIPE_BUF_FLAG_GIFT 0x04 /* page is a gift */
#define PIPE_BUF_FLAG_PACKET 0x08 /* read() as a packet */ #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 * struct pipe_buffer - a linux kernel pipe buffer
@ -69,11 +70,11 @@ struct pipe_inode_info {
* Note on the nesting of these functions: * Note on the nesting of these functions:
* *
* ->confirm() * ->confirm()
* ->steal() * ->try_steal()
* *
* That is, ->steal() must be called on a confirmed buffer. * That is, ->try_steal() must be called on a confirmed buffer. See below for
* See below for the meaning of each operation. Also see kerneldoc * the meaning of each operation. Also see the kerneldoc in fs/pipe.c for the
* in fs/pipe.c for the pipe and generic variants of these hooks. * pipe and generic variants of these hooks.
*/ */
struct pipe_buf_operations { 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 * 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 * 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 * 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 *); 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. * Attempt to take ownership of the pipe buffer and its contents.
* ->steal() returns 0 for success, in which case the contents * ->try_steal() returns %true for success, in which case the contents
* of the pipe (the buf->page) is locked and now completely owned * of the pipe (the buf->page) is locked and now completely owned by the
* by the caller. The page may then be transferred to a different * caller. The page may then be transferred to a different mapping, the
* mapping, the most often used case is insertion into different * most often used case is insertion into different file address space
* file address space cache. * 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. * 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, static inline int pipe_buf_confirm(struct pipe_inode_info *pipe,
struct pipe_buffer *buf) struct pipe_buffer *buf)
{ {
if (!buf->ops->confirm)
return 0;
return buf->ops->confirm(pipe, buf); 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 * @pipe: the pipe that the buffer belongs to
* @buf: the buffer to attempt to steal * @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) 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 /* 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 */ /* Generic pipe buffer ops functions */
bool generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *); bool generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *);
int generic_pipe_buf_confirm(struct pipe_inode_info *, struct pipe_buffer *); bool generic_pipe_buf_try_steal(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 *);
void generic_pipe_buf_release(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; extern const struct pipe_buf_operations nosteal_pipe_buf_ops;

View File

@ -1177,10 +1177,9 @@ static void relay_pipe_buf_release(struct pipe_inode_info *pipe,
} }
static const struct pipe_buf_operations relay_pipe_buf_ops = { static const struct pipe_buf_operations relay_pipe_buf_ops = {
.confirm = generic_pipe_buf_confirm, .release = relay_pipe_buf_release,
.release = relay_pipe_buf_release, .try_steal = generic_pipe_buf_try_steal,
.steal = generic_pipe_buf_steal, .get = generic_pipe_buf_get,
.get = generic_pipe_buf_get,
}; };
static void relay_page_release(struct splice_pipe_desc *spd, unsigned int i) static void relay_page_release(struct splice_pipe_desc *spd, unsigned int i)

View File

@ -6305,13 +6305,6 @@ static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
__free_page(spd->pages[idx]); __free_page(spd->pages[idx]);
} }
static const struct pipe_buf_operations tracing_pipe_buf_ops = {
.confirm = generic_pipe_buf_confirm,
.release = generic_pipe_buf_release,
.steal = generic_pipe_buf_steal,
.get = generic_pipe_buf_get,
};
static size_t static size_t
tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter) tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
{ {
@ -6373,7 +6366,7 @@ static ssize_t tracing_splice_read_pipe(struct file *filp,
.partial = partial_def, .partial = partial_def,
.nr_pages = 0, /* This gets updated below. */ .nr_pages = 0, /* This gets updated below. */
.nr_pages_max = PIPE_DEF_BUFFERS, .nr_pages_max = PIPE_DEF_BUFFERS,
.ops = &tracing_pipe_buf_ops, .ops = &default_pipe_buf_ops,
.spd_release = tracing_spd_release_pipe, .spd_release = tracing_spd_release_pipe,
}; };
ssize_t ret; ssize_t ret;
@ -7582,9 +7575,7 @@ static bool buffer_pipe_buf_get(struct pipe_inode_info *pipe,
/* Pipe buffer operations for a buffer. */ /* Pipe buffer operations for a buffer. */
static const struct pipe_buf_operations buffer_pipe_buf_ops = { static const struct pipe_buf_operations buffer_pipe_buf_ops = {
.confirm = generic_pipe_buf_confirm,
.release = buffer_pipe_buf_release, .release = buffer_pipe_buf_release,
.steal = generic_pipe_buf_nosteal,
.get = buffer_pipe_buf_get, .get = buffer_pipe_buf_get,
}; };

View File

@ -129,16 +129,8 @@ static void smc_rx_pipe_buf_release(struct pipe_inode_info *pipe,
sock_put(sk); sock_put(sk);
} }
static int smc_rx_pipe_buf_nosteal(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
return 1;
}
static const struct pipe_buf_operations smc_pipe_ops = { static const struct pipe_buf_operations smc_pipe_ops = {
.confirm = generic_pipe_buf_confirm,
.release = smc_rx_pipe_buf_release, .release = smc_rx_pipe_buf_release,
.steal = smc_rx_pipe_buf_nosteal,
.get = generic_pipe_buf_get .get = generic_pipe_buf_get
}; };