linux-ext4 - [PATCH 04/19] libext2fs: refactor aligned MMP buffer allocation

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Message-ID: <176246793699.2862242.1893342981035270584.stgit@frogsfrogsfrogs>
Date: Thu, 06 Nov 2025 14:32:08 -0800
From: "Darrick J. Wong" <djwong@...nel.org>
To: tytso@....edu
Cc: linux-ext4@...r.kernel.org
Subject: [PATCH 04/19] libext2fs: refactor aligned MMP buffer allocation

From: Darrick J. Wong <djwong@...nel.org>

Hoist the code that allocates an MMP buffer into a separate helper.

Signed-off-by: "Darrick J. Wong" <djwong@...nel.org>
---
 lib/ext2fs/ext2fs.h          |    1 +
 debian/libext2fs2t64.symbols |    1 +
 lib/ext2fs/dupfs.c           |    5 +----
 lib/ext2fs/mmp.c             |   12 ++++++++----
 4 files changed, 11 insertions(+), 8 deletions(-)


diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index dec48b80d341db..c4fcb10bea0fb9 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -1861,6 +1861,7 @@ errcode_t ext2fs_mmp_update(ext2_filsys fs);
 errcode_t ext2fs_mmp_update2(ext2_filsys fs, int immediately);
 errcode_t ext2fs_mmp_stop(ext2_filsys fs);
 unsigned ext2fs_mmp_new_seq(void);
+errcode_t ext2fs_mmp_get_mem(ext2_filsys fs, void **ptr);
 
 /* read_bb.c */
 extern errcode_t ext2fs_read_bb_inode(ext2_filsys fs,
diff --git a/debian/libext2fs2t64.symbols b/debian/libext2fs2t64.symbols
index 01f4f269a2660e..affe4c27d4e791 100644
--- a/debian/libext2fs2t64.symbols
+++ b/debian/libext2fs2t64.symbols
@@ -448,6 +448,7 @@ libext2fs.so.2 libext2fs2t64 #MINVER#
  ext2fs_mmp_clear@...e 1.42
  ext2fs_mmp_csum_set@...e 1.43
  ext2fs_mmp_csum_verify@...e 1.43
+ ext2fs_mmp_get_mem@...e 1.47.4
  ext2fs_mmp_init@...e 1.42
  ext2fs_mmp_new_seq@...e 1.42
  ext2fs_mmp_read@...e 1.42
diff --git a/lib/ext2fs/dupfs.c b/lib/ext2fs/dupfs.c
index 02721e1a574a1f..0fd4e6c67afb5d 100644
--- a/lib/ext2fs/dupfs.c
+++ b/lib/ext2fs/dupfs.c
@@ -104,10 +104,7 @@ errcode_t ext2fs_dup_handle(ext2_filsys src, ext2_filsys *dest)
 		}
 	}
 	if (src->mmp_cmp) {
-		int align = ext2fs_get_dio_alignment(src->mmp_fd);
-
-		retval = ext2fs_get_memalign(src->blocksize, align,
-					     &fs->mmp_cmp);
+		retval = ext2fs_mmp_get_mem(src, &fs->mmp_cmp);
 		if (retval)
 			goto errout;
 		memcpy(fs->mmp_cmp, src->mmp_cmp, src->blocksize);
diff --git a/lib/ext2fs/mmp.c b/lib/ext2fs/mmp.c
index 6337852c3f6700..41ef4e3e2aa6c5 100644
--- a/lib/ext2fs/mmp.c
+++ b/lib/ext2fs/mmp.c
@@ -41,6 +41,13 @@
 #endif
 #endif
 
+errcode_t ext2fs_mmp_get_mem(ext2_filsys fs, void **ptr)
+{
+	int align = ext2fs_get_dio_alignment(fs->mmp_fd);
+
+	return ext2fs_get_memalign(fs->blocksize, align, ptr);
+}
+
 errcode_t ext2fs_mmp_read(ext2_filsys fs, blk64_t mmp_blk, void *buf)
 {
 #ifdef CONFIG_MMP
@@ -78,10 +85,7 @@ errcode_t ext2fs_mmp_read(ext2_filsys fs, blk64_t mmp_blk, void *buf)
 	}
 
 	if (fs->mmp_cmp == NULL) {
-		int align = ext2fs_get_dio_alignment(fs->mmp_fd);
-
-		retval = ext2fs_get_memalign(fs->blocksize, align,
-					     &fs->mmp_cmp);
+		retval = ext2fs_mmp_get_mem(fs, &fs->mmp_cmp);
 		if (retval)
 			return retval;
 	}