kfree(spd->partial);
}
-/*
- * Splice data from an O_DIRECT file into pages and then add them to the output
- * pipe.
+/**
+ * copy_splice_read - Copy data from a file and splice the copy into a pipe
+ * @in: The file to read from
+ * @ppos: Pointer to the file position to read from
+ * @pipe: The pipe to splice into
+ * @len: The amount to splice
+ * @flags: The SPLICE_F_* flags
+ *
+ * This function allocates a bunch of pages sufficient to hold the requested
+ * amount of data (but limited by the remaining pipe capacity), passes it to
+ * the file's ->read_iter() to read into and then splices the used pages into
+ * the pipe.
+ *
+ * Return: On success, the number of bytes read will be returned and *@ppos
+ * will be updated if appropriate; 0 will be returned if there is no more data
+ * to be read; -EAGAIN will be returned if the pipe had no space, and some
+ * other negative error code will be returned on error. A short read may occur
+ * if the pipe has insufficient space, we reach the end of the data or we hit a
+ * hole.
*/
-ssize_t direct_splice_read(struct file *in, loff_t *ppos,
- struct pipe_inode_info *pipe,
- size_t len, unsigned int flags)
+ssize_t copy_splice_read(struct file *in, loff_t *ppos,
+ struct pipe_inode_info *pipe,
+ size_t len, unsigned int flags)
{
struct iov_iter to;
struct bio_vec *bv;
struct kiocb kiocb;
struct page **pages;
ssize_t ret;
- size_t used, npages, chunk, remain, reclaim;
+ size_t used, npages, chunk, remain, keep = 0;
int i;
/* Work out how much data we can actually add into the pipe */
if (!bv)
return -ENOMEM;
- pages = (void *)(bv + npages);
+ pages = (struct page **)(bv + npages);
npages = alloc_pages_bulk_array(GFP_USER, npages, pages);
if (!npages) {
kfree(bv);
kiocb.ki_pos = *ppos;
ret = call_read_iter(in, &kiocb, &to);
- reclaim = npages * PAGE_SIZE;
- remain = 0;
if (ret > 0) {
- reclaim -= ret;
- remain = ret;
+ keep = DIV_ROUND_UP(ret, PAGE_SIZE);
*ppos = kiocb.ki_pos;
- file_accessed(in);
- } else if (ret < 0) {
- /*
- * callers of ->splice_read() expect -EAGAIN on
- * "can't put anything in there", rather than -EFAULT.
- */
- if (ret == -EFAULT)
- ret = -EAGAIN;
}
+ /*
+ * Callers of ->splice_read() expect -EAGAIN on "can't put anything in
+ * there", rather than -EFAULT.
+ */
+ if (ret == -EFAULT)
+ ret = -EAGAIN;
+
/* Free any pages that didn't get touched at all. */
- reclaim /= PAGE_SIZE;
- if (reclaim) {
- npages -= reclaim;
- release_pages(pages + npages, reclaim);
- }
+ if (keep < npages)
+ release_pages(pages + keep, npages - keep);
/* Push the remaining pages into the pipe. */
- for (i = 0; i < npages; i++) {
+ remain = ret;
+ for (i = 0; i < keep; i++) {
struct pipe_buffer *buf = pipe_head_buf(pipe);
chunk = min_t(size_t, remain, PAGE_SIZE);
kfree(bv);
return ret;
}
-EXPORT_SYMBOL(direct_splice_read);
-
-/**
- * generic_file_splice_read - splice data from file to a pipe
- * @in: file to splice from
- * @ppos: position in @in
- * @pipe: pipe to splice to
- * @len: number of bytes to splice
- * @flags: splice modifier flags
- *
- * Description:
- * Will read pages from given file and fill them into a pipe. Can be
- * used as long as it has more or less sane ->read_iter().
- *
- */
-ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
- struct pipe_inode_info *pipe, size_t len,
- unsigned int flags)
-{
- struct iov_iter to;
- struct kiocb kiocb;
- int ret;
-
- iov_iter_pipe(&to, ITER_DEST, pipe, len);
- init_sync_kiocb(&kiocb, in);
- kiocb.ki_pos = *ppos;
- ret = call_read_iter(in, &kiocb, &to);
- if (ret > 0) {
- *ppos = kiocb.ki_pos;
- file_accessed(in);
- } else if (ret < 0) {
- /* free what was emitted */
- pipe_discard_from(pipe, to.start_head);
- /*
- * callers of ->splice_read() expect -EAGAIN on
- * "can't put anything in there", rather than -EFAULT.
- */
- if (ret == -EFAULT)
- ret = -EAGAIN;
- }
-
- return ret;
-}
-EXPORT_SYMBOL(generic_file_splice_read);
+EXPORT_SYMBOL(copy_splice_read);
const struct pipe_buf_operations default_pipe_buf_ops = {
.release = generic_pipe_buf_release,
sd->splice_eof(sd);
}
-/*
- * Attempt to initiate a splice from a file to a pipe.
+/**
+ * vfs_splice_read - Read data from a file and splice it into a pipe
+ * @in: File to splice from
+ * @ppos: Input file offset
+ * @pipe: Pipe to splice to
+ * @len: Number of bytes to splice
+ * @flags: Splice modifier flags (SPLICE_F_*)
+ *
+ * Splice the requested amount of data from the input file to the pipe. This
+ * is synchronous as the caller must hold the pipe lock across the entire
+ * operation.
+ *
+ * If successful, it returns the amount of data spliced, 0 if it hit the EOF or
+ * a hole and a negative error code otherwise.
*/
-static long do_splice_to(struct file *in, loff_t *ppos,
- struct pipe_inode_info *pipe, size_t len,
- unsigned int flags)
+long vfs_splice_read(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;
+ if (!len)
+ return 0;
/* Don't try to read more the pipe has space for. */
p_space = pipe->max_usage - pipe_occupancy(pipe->head, pipe->tail);
if (unlikely(!in->f_op->splice_read))
return warn_unsupported(in, "read");
+ /*
+ * O_DIRECT and DAX don't deal with the pagecache, so we allocate a
+ * buffer, copy into it and splice that into the pipe.
+ */
+ if ((in->f_flags & O_DIRECT) || IS_DAX(in->f_mapping->host))
+ return copy_splice_read(in, ppos, pipe, len, flags);
return in->f_op->splice_read(in, ppos, pipe, len, flags);
}
+EXPORT_SYMBOL_GPL(vfs_splice_read);
/**
* splice_direct_to_actor - splices data directly between two non-pipes
size_t read_len;
loff_t pos = sd->pos, prev_pos = pos;
- ret = do_splice_to(in, &pos, pipe, len, flags);
+ ret = vfs_splice_read(in, &pos, pipe, len, flags);
if (unlikely(ret <= 0))
goto read_failure;
pipe_lock(opipe);
ret = wait_for_space(opipe, flags);
if (!ret)
- ret = do_splice_to(in, offset, opipe, len, flags);
+ ret = vfs_splice_read(in, offset, opipe, len, flags);
pipe_unlock(opipe);
if (ret > 0)
wakeup_pipe_readers(opipe);
projects / platform / kernel / linux-starfive.git / blobdiff