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

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Pull sendfile updates from Al Viro:
 "Make sendfile() to pipe destination do the right thing, should make
  'fs/pipe: allow sendfile() to pipe again' redundant"

* 'work.sendfile' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  teach sendfile(2) to handle send-to-pipe directly
  take the guts of file-to-pipe splice into a helper function
  do_splice_to(): move the logics for limiting the read length in
This commit is contained in:
Linus Torvalds 2021-02-21 09:25:32 -08:00
commit 054560e961
3 changed files with 46 additions and 26 deletions
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9
fs/internal.h
View File

@ -15,6 +15,7 @@ struct mount;
struct shrink_control;
struct fs_context;
struct user_namespace;
struct pipe_inode_info;
/*
* block_dev.c
@ -193,3 +194,11 @@ int sb_init_dio_done_wq(struct super_block *sb);
*/
int do_statx(int dfd, const char __user *filename, unsigned flags,
unsigned int mask, struct statx __user *buffer);
/*
* fs/splice.c:
*/
long splice_file_to_pipe(struct file *in,
struct pipe_inode_info *opipe,
loff_t *offset,
size_t len, unsigned int flags);

19
fs/read_write.c
View File

@ -1188,6 +1188,7 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
{
struct fd in, out;
struct inode *in_inode, *out_inode;
struct pipe_inode_info *opipe;
loff_t pos;
loff_t out_pos;
ssize_t retval;
@ -1228,9 +1229,6 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
in_inode = file_inode(in.file);
out_inode = file_inode(out.file);
out_pos = out.file->f_pos;
retval = rw_verify_area(WRITE, out.file, &out_pos, count);
if (retval < 0)
goto fput_out;
if (!max)
max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
@ -1253,9 +1251,18 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
if (in.file->f_flags & O_NONBLOCK)
fl = SPLICE_F_NONBLOCK;
#endif
file_start_write(out.file);
retval = do_splice_direct(in.file, &pos, out.file, &out_pos, count, fl);
file_end_write(out.file);
opipe = get_pipe_info(out.file, true);
if (!opipe) {
retval = rw_verify_area(WRITE, out.file, &out_pos, count);
if (retval < 0)
goto fput_out;
file_start_write(out.file);
retval = do_splice_direct(in.file, &pos, out.file, &out_pos,
count, fl);
file_end_write(out.file);
} else {
retval = splice_file_to_pipe(in.file, opipe, &pos, count, fl);
}
if (retval > 0) {
add_rchar(current, retval);

44
fs/splice.c
View File

@ -771,11 +771,16 @@ static long do_splice_to(struct file *in, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len,
unsigned int flags)
{
unsigned int p_space;
int ret;
if (unlikely(!(in->f_mode & FMODE_READ)))
return -EBADF;
/* Don't try to read more the pipe has space for. */
p_space = pipe->max_usage - pipe_occupancy(pipe->head, pipe->tail);
len = min_t(size_t, len, p_space << PAGE_SHIFT);
ret = rw_verify_area(READ, in, ppos, len);
if (unlikely(ret < 0))
return ret;
@ -856,15 +861,10 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
WARN_ON_ONCE(!pipe_empty(pipe->head, pipe->tail));
while (len) {
unsigned int p_space;
size_t read_len;
loff_t pos = sd->pos, prev_pos = pos;
/* Don't try to read more the pipe has space for. */
p_space = pipe->max_usage -
pipe_occupancy(pipe->head, pipe->tail);
read_len = min_t(size_t, len, p_space << PAGE_SHIFT);
ret = do_splice_to(in, &pos, pipe, read_len, flags);
ret = do_splice_to(in, &pos, pipe, len, flags);
if (unlikely(ret <= 0))
goto out_release;
@ -1002,6 +1002,23 @@ static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe,
struct pipe_inode_info *opipe,
size_t len, unsigned int flags);
long splice_file_to_pipe(struct file *in,
struct pipe_inode_info *opipe,
loff_t *offset,
size_t len, unsigned int flags)
{
long ret;
pipe_lock(opipe);
ret = wait_for_space(opipe, flags);
if (!ret)
ret = do_splice_to(in, offset, opipe, len, flags);
pipe_unlock(opipe);
if (ret > 0)
wakeup_pipe_readers(opipe);
return ret;
}
/*
* Determine where to splice to/from.
*/
@ -1081,20 +1098,7 @@ long do_splice(struct file *in, loff_t *off_in, struct file *out,
if (out->f_flags & O_NONBLOCK)
flags |= SPLICE_F_NONBLOCK;
pipe_lock(opipe);
ret = wait_for_space(opipe, flags);
if (!ret) {
unsigned int p_space;
/* Don't try to read more the pipe has space for. */
p_space = opipe->max_usage - pipe_occupancy(opipe->head, opipe->tail);
len = min_t(size_t, len, p_space << PAGE_SHIFT);
ret = do_splice_to(in, &offset, opipe, len, flags);
}
pipe_unlock(opipe);
if (ret > 0)
wakeup_pipe_readers(opipe);
ret = splice_file_to_pipe(in, opipe, &offset, len, flags);
if (!off_in)
in->f_pos = offset;
else