diff options
| author |   Jann Horn <jannh@google.com> | 2019-01-23 15:19:18 +0100 |
|---|---|---|
| committer |   Al Viro <viro@zeniv.linux.org.uk> | 2019-02-01 02:01:45 -0500 |
| commit | 01e7187b41191376cee8bea8de9f907b001e87b4 (patch) | |
| tree | 024b8f4afcf6bb85a5daafc475c47187b40435d3 /fs | |
| parent | splice: don't merge into linked buffers (diff) | |
| download | linux-dev-01e7187b41191376cee8bea8de9f907b001e87b4.tar.xz linux-dev-01e7187b41191376cee8bea8de9f907b001e87b4.zip | |
pipe: stop using ->can_merge
Al Viro pointed out that since there is only one pipe buffer type to which
new data can be appended, it isn't necessary to have a ->can_merge field in
struct pipe_buf_operations, we can just check for a magic type.
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/pipe.c | 20 | ||||
| -rw-r--r-- | fs/splice.c | 4 |
2 files changed, 16 insertions, 8 deletions
diff --git a/fs/pipe.c b/fs/pipe.c index c51750ed4011..0ff09b490ddf 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -226,8 +226,8 @@ 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 = { - .can_merge = 1, .confirm = generic_pipe_buf_confirm, .release = anon_pipe_buf_release, .steal = anon_pipe_buf_steal, @@ -235,7 +235,6 @@ static const struct pipe_buf_operations anon_pipe_buf_ops = { }; static const struct pipe_buf_operations anon_pipe_buf_nomerge_ops = { - .can_merge = 0, .confirm = generic_pipe_buf_confirm, .release = anon_pipe_buf_release, .steal = anon_pipe_buf_steal, @@ -243,19 +242,32 @@ static const struct pipe_buf_operations anon_pipe_buf_nomerge_ops = { }; static const struct pipe_buf_operations packet_pipe_buf_ops = { - .can_merge = 0, .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; +} + static ssize_t pipe_read(struct kiocb *iocb, struct iov_iter *to) { @@ -393,7 +405,7 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from) struct pipe_buffer *buf = pipe->bufs + lastbuf; int offset = buf->offset + buf->len; - if (buf->ops->can_merge && offset + chars <= PAGE_SIZE) { + if (pipe_buf_can_merge(buf) && offset + chars <= PAGE_SIZE) { ret = pipe_buf_confirm(pipe, buf); if (ret) goto out; diff --git a/fs/splice.c b/fs/splice.c index 90c29675d573..fc71e9733f7a 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -138,7 +138,6 @@ error: } const struct pipe_buf_operations page_cache_pipe_buf_ops = { - .can_merge = 0, .confirm = page_cache_pipe_buf_confirm, .release = page_cache_pipe_buf_release, .steal = page_cache_pipe_buf_steal, @@ -156,7 +155,6 @@ static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, } static const struct pipe_buf_operations user_page_pipe_buf_ops = { - .can_merge = 0, .confirm = generic_pipe_buf_confirm, .release = page_cache_pipe_buf_release, .steal = user_page_pipe_buf_steal, @@ -326,7 +324,6 @@ 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 = { - .can_merge = 0, .confirm = generic_pipe_buf_confirm, .release = generic_pipe_buf_release, .steal = generic_pipe_buf_steal, @@ -341,7 +338,6 @@ static int generic_pipe_buf_nosteal(struct pipe_inode_info *pipe, /* Pipe buffer operations for a socket and similar. */ const struct pipe_buf_operations nosteal_pipe_buf_ops = { - .can_merge = 0, .confirm = generic_pipe_buf_confirm, .release = generic_pipe_buf_release, .steal = generic_pipe_buf_nosteal, |