[PATCH 1/4] ceph: add ceph_folio_snap_context()

[Tal Zussman]

Add a folio-based counterpart to page_snap_context() that reads the
snap context from folio->private directly.

Convert the three writeback paths that passed &folio->page to
page_snap_context() to ceph_folio_snap_context(), removing three
open-coded folio-to-page conversions. No functional change.

Signed-off-by: Tal Zussman <tz2294@xxxxxxxxxxxx>
---
 fs/ceph/addr.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index ecf33b66610c..a8ed2a14da44 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -75,6 +75,13 @@ static inline struct ceph_snap_context *page_snap_context(struct page *page)
 	return NULL;
 }
 
+static inline struct ceph_snap_context *ceph_folio_snap_context(struct folio *folio)
+{
+	if (folio_test_private(folio))
+		return (void *)folio->private;
+	return NULL;
+}
+
 /*
  * Dirty a page.  Optimistically adjust accounting, on the assumption
  * that we won't race with invalidate.  If we do, readjust.
@@ -745,7 +752,7 @@ static int write_folio_nounlock(struct folio *folio,
 		return -EIO;
 
 	/* verify this is a writeable snap context */
-	snapc = page_snap_context(&folio->page);
+	snapc = ceph_folio_snap_context(folio);
 	if (!snapc) {
 		doutc(cl, "%llx.%llx folio %p not dirty?\n", ceph_vinop(inode),
 		      folio);
@@ -1171,7 +1178,7 @@ int ceph_check_page_before_write(struct address_space *mapping,
 	}
 
 	/* only if matching snap context */
-	pgsnapc = page_snap_context(&folio->page);
+	pgsnapc = ceph_folio_snap_context(folio);
 	if (pgsnapc != ceph_wbc->snapc) {
 		doutc(cl, "folio snapc %p %lld != oldest %p %lld\n",
 		      pgsnapc, pgsnapc->seq,
@@ -1824,7 +1831,7 @@ ceph_find_incompatible(struct folio *folio)
 
 		folio_wait_writeback(folio);
 
-		snapc = page_snap_context(&folio->page);
+		snapc = ceph_folio_snap_context(folio);
 		if (!snapc || snapc == ci->i_head_snapc)
 			break;
 

-- 
2.39.5