switch generic_file_splice_read() to use of ->read_iter()
... and kill the ->splice_read() instances that can be switched to it
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/mm/shmem.c b/mm/shmem.c
index 971fc83..d86b5e4 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2311,119 +2311,6 @@
return retval ? retval : error;
}
-static ssize_t shmem_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;
- struct inode *inode = mapping->host;
- unsigned int loff, nr_pages, req_pages;
- struct page *pages[PIPE_DEF_BUFFERS];
- struct partial_page partial[PIPE_DEF_BUFFERS];
- struct page *page;
- pgoff_t index, end_index;
- loff_t isize, left;
- int error, page_nr;
- struct splice_pipe_desc spd = {
- .pages = pages,
- .partial = partial,
- .nr_pages_max = PIPE_DEF_BUFFERS,
- .flags = flags,
- .ops = &page_cache_pipe_buf_ops,
- .spd_release = spd_release_page,
- };
-
- isize = i_size_read(inode);
- if (unlikely(*ppos >= isize))
- return 0;
-
- left = isize - *ppos;
- if (unlikely(left < len))
- len = left;
-
- if (splice_grow_spd(pipe, &spd))
- return -ENOMEM;
-
- index = *ppos >> PAGE_SHIFT;
- loff = *ppos & ~PAGE_MASK;
- req_pages = (len + loff + PAGE_SIZE - 1) >> PAGE_SHIFT;
- nr_pages = min(req_pages, spd.nr_pages_max);
-
- spd.nr_pages = find_get_pages_contig(mapping, index,
- nr_pages, spd.pages);
- index += spd.nr_pages;
- error = 0;
-
- while (spd.nr_pages < nr_pages) {
- error = shmem_getpage(inode, index, &page, SGP_CACHE);
- if (error)
- break;
- unlock_page(page);
- spd.pages[spd.nr_pages++] = page;
- index++;
- }
-
- index = *ppos >> PAGE_SHIFT;
- nr_pages = spd.nr_pages;
- spd.nr_pages = 0;
-
- for (page_nr = 0; page_nr < nr_pages; page_nr++) {
- unsigned int this_len;
-
- if (!len)
- break;
-
- this_len = min_t(unsigned long, len, PAGE_SIZE - loff);
- page = spd.pages[page_nr];
-
- if (!PageUptodate(page) || page->mapping != mapping) {
- error = shmem_getpage(inode, index, &page, SGP_CACHE);
- if (error)
- break;
- unlock_page(page);
- put_page(spd.pages[page_nr]);
- spd.pages[page_nr] = page;
- }
-
- isize = i_size_read(inode);
- end_index = (isize - 1) >> PAGE_SHIFT;
- if (unlikely(!isize || index > end_index))
- break;
-
- if (end_index == index) {
- unsigned int plen;
-
- plen = ((isize - 1) & ~PAGE_MASK) + 1;
- if (plen <= loff)
- break;
-
- this_len = min(this_len, plen - loff);
- len = this_len;
- }
-
- spd.partial[page_nr].offset = loff;
- spd.partial[page_nr].len = this_len;
- len -= this_len;
- loff = 0;
- spd.nr_pages++;
- index++;
- }
-
- while (page_nr < nr_pages)
- put_page(spd.pages[page_nr++]);
-
- if (spd.nr_pages)
- error = splice_to_pipe(pipe, &spd);
-
- splice_shrink_spd(&spd);
-
- if (error > 0) {
- *ppos += error;
- file_accessed(in);
- }
- return error;
-}
-
/*
* llseek SEEK_DATA or SEEK_HOLE through the radix_tree.
*/
@@ -3786,7 +3673,7 @@
.read_iter = shmem_file_read_iter,
.write_iter = generic_file_write_iter,
.fsync = noop_fsync,
- .splice_read = shmem_file_splice_read,
+ .splice_read = generic_file_splice_read,
.splice_write = iter_file_splice_write,
.fallocate = shmem_fallocate,
#endif