linux-ext4 - [PATCH 01/10] highmem: Add folio_release

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20230921200746.3303942-1-willy@infradead.org>
Date:   Thu, 21 Sep 2023 21:07:38 +0100
From:   "Matthew Wilcox (Oracle)" <willy@...radead.org>
To:     Jan Kara <jack@...e.com>
Cc:     "Matthew Wilcox (Oracle)" <willy@...radead.org>,
        linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        "Fabio M . De Francesco" <fmdefrancesco@...il.com>
Subject: [PATCH 01/10] highmem: Add folio_release_kmap()

This is the folio equivalent of unmap_and_put_page(), which remains as
a wrapper for it.

Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
---
 include/linux/highmem.h | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index 99c474de800d..4cacc0e43b51 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -551,10 +551,24 @@ static inline void folio_zero_range(struct folio *folio,
 	zero_user_segments(&folio->page, start, start + length, 0, 0);
 }
 
-static inline void unmap_and_put_page(struct page *page, void *addr)
+/**
+ * folio_release_kmap - Unmap a folio and drop a refcount.
+ * @folio: The folio to release.
+ * @addr: The address previously returned by a call to kmap_local_folio().
+ *
+ * It is common, eg in directory handling to kmap a folio.  This function
+ * unmaps the folio and drops the refcount that was being held to keep the
+ * folio alive while we accessed it.
+ */
+static inline void folio_release_kmap(struct folio *folio, void *addr)
 {
 	kunmap_local(addr);
-	put_page(page);
+	folio_put(folio);
+}
+
+static inline void unmap_and_put_page(struct page *page, void *addr)
+{
+	folio_release_kmap(page_folio(page), addr);
 }
 
 #endif /* _LINUX_HIGHMEM_H */
-- 
2.40.1