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Message-Id: <20201216182335.27227-26-willy@infradead.org>
Date: Wed, 16 Dec 2020 18:23:35 +0000
From: "Matthew Wilcox (Oracle)" <willy@...radead.org>
To: linux-fsdevel@...r.kernel.org, linux-mm@...ck.org
Cc: "Matthew Wilcox (Oracle)" <willy@...radead.org>,
linux-kernel@...r.kernel.org
Subject: [PATCH 25/25] fs: Convert vfs_dedupe_file_range_compare to folios
Simplify the implementation somewhat by working in pgoff_t instead
of loff_t. We still only operate on a single page of data at a time
due to using kmap(). A more complex implementation would work on
an entire folio at a time and (if the pages are highmem) map and
unmap, but it's not clear that such a complex implementation would
be worthwhile.
Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
---
fs/remap_range.c | 109 ++++++++++++++++++++++-------------------------
1 file changed, 52 insertions(+), 57 deletions(-)
diff --git a/fs/remap_range.c b/fs/remap_range.c
index 77dba3a49e65..0ee52c2da2cf 100644
--- a/fs/remap_range.c
+++ b/fs/remap_range.c
@@ -158,41 +158,41 @@ static int generic_remap_check_len(struct inode *inode_in,
}
/* Read a page's worth of file data into the page cache. */
-static struct page *vfs_dedupe_get_page(struct inode *inode, loff_t offset)
+static struct folio *vfs_dedupe_get_folio(struct inode *inode, pgoff_t index)
{
- struct page *page;
+ struct folio *folio;
- page = read_mapping_page(inode->i_mapping, offset >> PAGE_SHIFT, NULL);
- if (IS_ERR(page))
- return page;
- if (!PageUptodate(page)) {
- put_page(page);
+ folio = read_mapping_folio(inode->i_mapping, index, NULL);
+ if (IS_ERR(folio))
+ return folio;
+ if (!FolioUptodate(folio)) {
+ put_folio(folio);
return ERR_PTR(-EIO);
}
- return page;
+ return folio;
}
/*
- * Lock two pages, ensuring that we lock in offset order if the pages are from
- * the same file.
+ * Lock two folios, ensuring that we lock in offset order if the folios
+ * are from the same file.
*/
-static void vfs_lock_two_pages(struct page *page1, struct page *page2)
+static void vfs_lock_two_folios(struct folio *folio1, struct folio *folio2)
{
/* Always lock in order of increasing index. */
- if (page1->index > page2->index)
- swap(page1, page2);
+ if (folio_index(folio1) > folio_index(folio2))
+ swap(folio1, folio2);
- lock_page(page1);
- if (page1 != page2)
- lock_page(page2);
+ lock_folio(folio1);
+ if (folio1 != folio2)
+ lock_folio(folio2);
}
-/* Unlock two pages, being careful not to unlock the same page twice. */
-static void vfs_unlock_two_pages(struct page *page1, struct page *page2)
+/* Unlock two folios, being careful not to unlock the same folio twice. */
+static void vfs_unlock_two_folios(struct folio *folio1, struct folio *folio2)
{
- unlock_page(page1);
- if (page1 != page2)
- unlock_page(page2);
+ unlock_folio(folio1);
+ if (folio1 != folio2)
+ unlock_folio(folio2);
}
/*
@@ -203,68 +203,63 @@ static int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
struct inode *dest, loff_t destoff,
loff_t len, bool *is_same)
{
- loff_t src_poff;
- loff_t dest_poff;
- void *src_addr;
- void *dest_addr;
- struct page *src_page;
- struct page *dest_page;
- loff_t cmp_len;
- bool same;
- int error;
-
- error = -EINVAL;
- same = true;
+ bool same = true;
+ int error = -EINVAL;
+
while (len) {
- src_poff = srcoff & (PAGE_SIZE - 1);
- dest_poff = destoff & (PAGE_SIZE - 1);
- cmp_len = min(PAGE_SIZE - src_poff,
- PAGE_SIZE - dest_poff);
+ struct folio *src_folio, *dst_folio;
+ void *src_addr, *dest_addr;
+ pgoff_t src_index = srcoff / PAGE_SIZE;
+ pgoff_t dst_index = destoff / PAGE_SIZE;
+ loff_t cmp_len = min(PAGE_SIZE - offset_in_page(srcoff),
+ PAGE_SIZE - offset_in_page(destoff));
+
cmp_len = min(cmp_len, len);
if (cmp_len <= 0)
goto out_error;
- src_page = vfs_dedupe_get_page(src, srcoff);
- if (IS_ERR(src_page)) {
- error = PTR_ERR(src_page);
+ src_folio = vfs_dedupe_get_folio(src, src_index);
+ if (IS_ERR(src_folio)) {
+ error = PTR_ERR(src_folio);
goto out_error;
}
- dest_page = vfs_dedupe_get_page(dest, destoff);
- if (IS_ERR(dest_page)) {
- error = PTR_ERR(dest_page);
- put_page(src_page);
+ dst_folio = vfs_dedupe_get_folio(dest, dst_index);
+ if (IS_ERR(dst_folio)) {
+ error = PTR_ERR(dst_folio);
+ put_folio(src_folio);
goto out_error;
}
- vfs_lock_two_pages(src_page, dest_page);
+ vfs_lock_two_folios(src_folio, dst_folio);
/*
- * Now that we've locked both pages, make sure they're still
+ * Now that we've locked both folios, make sure they're still
* mapped to the file data we're interested in. If not,
* someone is invalidating pages on us and we lose.
*/
- if (!PageUptodate(src_page) || !PageUptodate(dest_page) ||
- src_page->mapping != src->i_mapping ||
- dest_page->mapping != dest->i_mapping) {
+ if (!FolioUptodate(src_folio) || !FolioUptodate(dst_folio) ||
+ folio_mapping(src_folio) != src->i_mapping ||
+ folio_mapping(dst_folio) != dest->i_mapping) {
same = false;
goto unlock;
}
- src_addr = kmap_atomic(src_page);
- dest_addr = kmap_atomic(dest_page);
+ src_addr = kmap_atomic(folio_page(src_folio, src_index));
+ dest_addr = kmap_atomic(folio_page(dst_folio, dst_index));
- flush_dcache_page(src_page);
- flush_dcache_page(dest_page);
+ flush_dcache_folio(src_folio);
+ flush_dcache_folio(dst_folio);
- if (memcmp(src_addr + src_poff, dest_addr + dest_poff, cmp_len))
+ if (memcmp(src_addr + offset_in_page(srcoff),
+ dest_addr + offset_in_page(destoff), cmp_len))
same = false;
kunmap_atomic(dest_addr);
kunmap_atomic(src_addr);
unlock:
- vfs_unlock_two_pages(src_page, dest_page);
- put_page(dest_page);
- put_page(src_page);
+ vfs_unlock_two_folios(src_folio, dst_folio);
+ put_folio(dst_folio);
+ put_folio(src_folio);
if (!same)
break;
--
2.29.2
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