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Message-ID: <161789075327.6155.7432127924219092385.stgit@warthog.procyon.org.uk>
Date: Thu, 08 Apr 2021 15:05:53 +0100
From: David Howells <dhowells@...hat.com>
To: linux-fsdevel@...r.kernel.org
Cc: Linus Torvalds <torvalds@...ux-foundation.org>,
Matthew Wilcox <willy@...radead.org>, linux-mm@...ck.org,
linux-cachefs@...hat.com, linux-afs@...ts.infradead.org,
linux-nfs@...r.kernel.org, linux-cifs@...r.kernel.org,
ceph-devel@...r.kernel.org, v9fs-developer@...ts.sourceforge.net,
dhowells@...hat.com,
Trond Myklebust <trond.myklebust@...merspace.com>,
Anna Schumaker <anna.schumaker@...app.com>,
Steve French <sfrench@...ba.org>,
Dominique Martinet <asmadeus@...ewreck.org>,
Jeff Layton <jlayton@...hat.com>,
David Wysochanski <dwysocha@...hat.com>,
"Matthew Wilcox (Oracle)" <willy@...radead.org>,
Alexander Viro <viro@...iv.linux.org.uk>,
linux-cachefs@...hat.com, linux-afs@...ts.infradead.org,
linux-nfs@...r.kernel.org, linux-cifs@...r.kernel.org,
ceph-devel@...r.kernel.org, v9fs-developer@...ts.sourceforge.net,
linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: [PATCH v6 09/30] netfs,
mm: Add set/end/wait_on_page_fscache() aliases
Add set/end/wait_on_page_fscache() as aliases of
set/end/wait_page_private_2(). These allow a page to marked with
PG_fscache, the flag to be removed and waiters woken and waiting for the
flag to be cleared. A ref on the page is also taken and dropped.
[Linus suggested putting the fscache-themed functions into the
caching-specific headers rather than pagemap.h[1]]
Changes:
v5:
- Mirror the changes to the core routines[2].
Signed-off-by: David Howells <dhowells@...hat.com>
cc: Linus Torvalds <torvalds@...ux-foundation.org>
cc: Matthew Wilcox <willy@...radead.org>
cc: linux-mm@...ck.org
cc: linux-cachefs@...hat.com
cc: linux-afs@...ts.infradead.org
cc: linux-nfs@...r.kernel.org
cc: linux-cifs@...r.kernel.org
cc: ceph-devel@...r.kernel.org
cc: v9fs-developer@...ts.sourceforge.net
cc: linux-fsdevel@...r.kernel.org
Link: https://lore.kernel.org/r/1330473.1612974547@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/CAHk-=wjgA-74ddehziVk=XAEMTKswPu1Yw4uaro1R3ibs27ztw@mail.gmail.com/ [1]
Link: https://lore.kernel.org/r/161340393568.1303470.4997526899111310530.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/161539536093.286939.5076448803512118764.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/2499407.1616505440@warthog.procyon.org.uk/ [2]
Link: https://lore.kernel.org/r/161653793873.2770958.12157243390965814502.stgit@warthog.procyon.org.uk/ # v5
---
include/linux/netfs.h | 57 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 57 insertions(+)
diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index cc1102040488..8479d63406f7 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -26,4 +26,61 @@
#define TestSetPageFsCache(page) TestSetPagePrivate2((page))
#define TestClearPageFsCache(page) TestClearPagePrivate2((page))
+/**
+ * set_page_fscache - Set PG_fscache on a page and take a ref
+ * @page: The page.
+ *
+ * Set the PG_fscache (PG_private_2) flag on a page and take the reference
+ * needed for the VM to handle its lifetime correctly. This sets the flag and
+ * takes the reference unconditionally, so care must be taken not to set the
+ * flag again if it's already set.
+ */
+static inline void set_page_fscache(struct page *page)
+{
+ set_page_private_2(page);
+}
+
+/**
+ * end_page_fscache - Clear PG_fscache and release any waiters
+ * @page: The page
+ *
+ * Clear the PG_fscache (PG_private_2) bit on a page and wake up any sleepers
+ * waiting for this. The page ref held for PG_private_2 being set is released.
+ *
+ * This is, for example, used when a netfs page is being written to a local
+ * disk cache, thereby allowing writes to the cache for the same page to be
+ * serialised.
+ */
+static inline void end_page_fscache(struct page *page)
+{
+ end_page_private_2(page);
+}
+
+/**
+ * wait_on_page_fscache - Wait for PG_fscache to be cleared on a page
+ * @page: The page to wait on
+ *
+ * Wait for PG_fscache (aka PG_private_2) to be cleared on a page.
+ */
+static inline void wait_on_page_fscache(struct page *page)
+{
+ wait_on_page_private_2(page);
+}
+
+/**
+ * wait_on_page_fscache_killable - Wait for PG_fscache to be cleared on a page
+ * @page: The page to wait on
+ *
+ * Wait for PG_fscache (aka PG_private_2) to be cleared on a page or until a
+ * fatal signal is received by the calling task.
+ *
+ * Return:
+ * - 0 if successful.
+ * - -EINTR if a fatal signal was encountered.
+ */
+static inline int wait_on_page_fscache_killable(struct page *page)
+{
+ return wait_on_page_private_2_killable(page);
+}
+
#endif /* _LINUX_NETFS_H */
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