[PATCH] splice: pass offset around for ->splice_read() and ->splice_write()
We need not use ->f_pos as the offset for the file input/output. If the
user passed an offset pointer in through sys_splice(), just use that and
leave ->f_pos alone.
Signed-off-by: Jens Axboe <axboe@suse.de>
diff --git a/fs/splice.c b/fs/splice.c
index e50a460..5d3eda6 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -231,8 +231,9 @@
}
static int
-__generic_file_splice_read(struct file *in, struct pipe_inode_info *pipe,
- size_t len, unsigned int flags)
+__generic_file_splice_read(struct file *in, loff_t *ppos,
+ struct pipe_inode_info *pipe, size_t len,
+ unsigned int flags)
{
struct address_space *mapping = in->f_mapping;
unsigned int offset, nr_pages;
@@ -241,8 +242,8 @@
pgoff_t index;
int i, error;
- index = in->f_pos >> PAGE_CACHE_SHIFT;
- offset = in->f_pos & ~PAGE_CACHE_MASK;
+ index = *ppos >> PAGE_CACHE_SHIFT;
+ offset = *ppos & ~PAGE_CACHE_MASK;
nr_pages = (len + offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
if (nr_pages > PIPE_BUFFERS)
@@ -348,8 +349,9 @@
*
* Will read pages from given file and fill them into a pipe.
*/
-ssize_t generic_file_splice_read(struct file *in, struct pipe_inode_info *pipe,
- size_t len, unsigned int flags)
+ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
+ struct pipe_inode_info *pipe, size_t len,
+ unsigned int flags)
{
ssize_t spliced;
int ret;
@@ -358,12 +360,12 @@
spliced = 0;
while (len) {
- ret = __generic_file_splice_read(in, pipe, len, flags);
+ ret = __generic_file_splice_read(in, ppos, pipe, len, flags);
if (ret <= 0)
break;
- in->f_pos += ret;
+ *ppos += ret;
len -= ret;
spliced += ret;
@@ -561,7 +563,7 @@
* to the wanted destination. See pipe_to_file/pipe_to_sendpage above.
*/
static ssize_t move_from_pipe(struct pipe_inode_info *pipe, struct file *out,
- size_t len, unsigned int flags,
+ loff_t *ppos, size_t len, unsigned int flags,
splice_actor *actor)
{
int ret, do_wakeup, err;
@@ -573,7 +575,7 @@
sd.total_len = len;
sd.flags = flags;
sd.file = out;
- sd.pos = out->f_pos;
+ sd.pos = *ppos;
if (pipe->inode)
mutex_lock(&pipe->inode->i_mutex);
@@ -656,9 +658,7 @@
kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
}
- out->f_pos = sd.pos;
return ret;
-
}
/**
@@ -674,12 +674,12 @@
*/
ssize_t
generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
- size_t len, unsigned int flags)
+ loff_t *ppos, size_t len, unsigned int flags)
{
struct address_space *mapping = out->f_mapping;
ssize_t ret;
- ret = move_from_pipe(pipe, out, len, flags, pipe_to_file);
+ ret = move_from_pipe(pipe, out, ppos, len, flags, pipe_to_file);
/*
* If file or inode is SYNC and we actually wrote some data, sync it.
@@ -715,9 +715,9 @@
*
*/
ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out,
- size_t len, unsigned int flags)
+ loff_t *ppos, size_t len, unsigned int flags)
{
- return move_from_pipe(pipe, out, len, flags, pipe_to_sendpage);
+ return move_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage);
}
EXPORT_SYMBOL(generic_splice_sendpage);
@@ -726,9 +726,8 @@
* Attempt to initiate a splice from pipe to file.
*/
static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
- size_t len, unsigned int flags)
+ loff_t *ppos, size_t len, unsigned int flags)
{
- loff_t pos;
int ret;
if (unlikely(!out->f_op || !out->f_op->splice_write))
@@ -737,22 +736,21 @@
if (unlikely(!(out->f_mode & FMODE_WRITE)))
return -EBADF;
- pos = out->f_pos;
-
- ret = rw_verify_area(WRITE, out, &pos, len);
+ ret = rw_verify_area(WRITE, out, ppos, len);
if (unlikely(ret < 0))
return ret;
- return out->f_op->splice_write(pipe, out, len, flags);
+ return out->f_op->splice_write(pipe, out, ppos, len, flags);
}
/*
* Attempt to initiate a splice from a file to a pipe.
*/
-static long do_splice_to(struct file *in, struct pipe_inode_info *pipe,
- size_t len, unsigned int flags)
+static long do_splice_to(struct file *in, loff_t *ppos,
+ struct pipe_inode_info *pipe, size_t len,
+ unsigned int flags)
{
- loff_t pos, isize, left;
+ loff_t isize, left;
int ret;
if (unlikely(!in->f_op || !in->f_op->splice_read))
@@ -761,28 +759,27 @@
if (unlikely(!(in->f_mode & FMODE_READ)))
return -EBADF;
- pos = in->f_pos;
-
- ret = rw_verify_area(READ, in, &pos, len);
+ ret = rw_verify_area(READ, in, ppos, len);
if (unlikely(ret < 0))
return ret;
isize = i_size_read(in->f_mapping->host);
- if (unlikely(in->f_pos >= isize))
+ if (unlikely(*ppos >= isize))
return 0;
- left = isize - in->f_pos;
+ left = isize - *ppos;
if (unlikely(left < len))
len = left;
- return in->f_op->splice_read(in, pipe, len, flags);
+ return in->f_op->splice_read(in, ppos, pipe, len, flags);
}
-long do_splice_direct(struct file *in, struct file *out, size_t len,
- unsigned int flags)
+long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
+ size_t len, unsigned int flags)
{
struct pipe_inode_info *pipe;
long ret, bytes;
+ loff_t out_off;
umode_t i_mode;
int i;
@@ -820,6 +817,7 @@
*/
ret = 0;
bytes = 0;
+ out_off = 0;
while (len) {
size_t read_len, max_read_len;
@@ -829,7 +827,7 @@
*/
max_read_len = min(len, (size_t)(PIPE_BUFFERS*PAGE_SIZE));
- ret = do_splice_to(in, pipe, max_read_len, flags);
+ ret = do_splice_to(in, ppos, pipe, max_read_len, flags);
if (unlikely(ret < 0))
goto out_release;
@@ -840,7 +838,7 @@
* must not do the output in nonblocking mode as then we
* could get stuck data in the internal pipe:
*/
- ret = do_splice_from(pipe, out, read_len,
+ ret = do_splice_from(pipe, out, &out_off, read_len,
flags & ~SPLICE_F_NONBLOCK);
if (unlikely(ret < 0))
goto out_release;
@@ -898,6 +896,7 @@
size_t len, unsigned int flags)
{
struct pipe_inode_info *pipe;
+ loff_t offset, *off;
pipe = in->f_dentry->d_inode->i_pipe;
if (pipe) {
@@ -906,12 +905,13 @@
if (off_out) {
if (out->f_op->llseek == no_llseek)
return -EINVAL;
- if (copy_from_user(&out->f_pos, off_out,
- sizeof(loff_t)))
+ if (copy_from_user(&offset, off_out, sizeof(loff_t)))
return -EFAULT;
- }
+ off = &offset;
+ } else
+ off = &out->f_pos;
- return do_splice_from(pipe, out, len, flags);
+ return do_splice_from(pipe, out, off, len, flags);
}
pipe = out->f_dentry->d_inode->i_pipe;
@@ -921,11 +921,13 @@
if (off_in) {
if (in->f_op->llseek == no_llseek)
return -EINVAL;
- if (copy_from_user(&in->f_pos, off_in, sizeof(loff_t)))
+ if (copy_from_user(&offset, off_in, sizeof(loff_t)))
return -EFAULT;
- }
+ off = &offset;
+ } else
+ off = &in->f_pos;
- return do_splice_to(in, pipe, len, flags);
+ return do_splice_to(in, off, pipe, len, flags);
}
return -EINVAL;