linux-kernel - [PATCH v2 31/35] ocfs2: Use kmemdup rather than duplicating its implementation

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Date:   Thu,  4 Jul 2019 00:31:47 +0800
From:   Fuqian Huang <huangfq.daxian@...il.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Mark Fasheh <mark@...heh.com>, Joel Becker <jlbec@...lplan.org>,
        Joseph Qi <joseph.qi@...ux.alibaba.com>,
        ocfs2-devel@....oracle.com, linux-kernel@...r.kernel.org,
        Fuqian Huang <huangfq.daxian@...il.com>
Subject: [PATCH v2 31/35] ocfs2: Use kmemdup rather than duplicating its implementation

kmemdup is introduced to duplicate a region of memory in a neat way.
Rather than kmalloc/kzalloc + memcpy, which the programmer needs to
write the size twice (sometimes lead to mistakes), kmemdup improves
readability, leads to smaller code and also reduce the chances of mistakes.
Suggestion to use kmemdup rather than using kmalloc/kzalloc + memcpy.

Signed-off-by: Fuqian Huang <huangfq.daxian@...il.com>
---
Changes in v2:
  - Fix a typo in commit message (memset -> memcpy)

 fs/ocfs2/alloc.c      | 8 +++-----
 fs/ocfs2/localalloc.c | 6 ++----
 2 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index d1348fc4ca6d..d4911d70c326 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -6191,17 +6191,15 @@ int ocfs2_begin_truncate_log_recovery(struct ocfs2_super *osb,
 	if (le16_to_cpu(tl->tl_used)) {
 		trace_ocfs2_truncate_log_recovery_num(le16_to_cpu(tl->tl_used));
 
-		*tl_copy = kmalloc(tl_bh->b_size, GFP_KERNEL);
+		/* Assuming the write-out below goes well, this copy
+		 * will be passed back to recovery for processing. */
+		*tl_copy = kmemdup(tl_bh->b_data, tl_bh->b_size, GFP_KERNEL);
 		if (!(*tl_copy)) {
 			status = -ENOMEM;
 			mlog_errno(status);
 			goto bail;
 		}
 
-		/* Assuming the write-out below goes well, this copy
-		 * will be passed back to recovery for processing. */
-		memcpy(*tl_copy, tl_bh->b_data, tl_bh->b_size);
-
 		/* All we need to do to clear the truncate log is set
 		 * tl_used. */
 		tl->tl_used = 0;
diff --git a/fs/ocfs2/localalloc.c b/fs/ocfs2/localalloc.c
index f03674afbd30..158e5af767fd 100644
--- a/fs/ocfs2/localalloc.c
+++ b/fs/ocfs2/localalloc.c
@@ -424,12 +424,11 @@ void ocfs2_shutdown_local_alloc(struct ocfs2_super *osb)
 	bh = osb->local_alloc_bh;
 	alloc = (struct ocfs2_dinode *) bh->b_data;
 
-	alloc_copy = kmalloc(bh->b_size, GFP_NOFS);
+	alloc_copy = kmemdup(alloc, bh->b_size, GFP_NOFS);
 	if (!alloc_copy) {
 		status = -ENOMEM;
 		goto out_commit;
 	}
-	memcpy(alloc_copy, alloc, bh->b_size);
 
 	status = ocfs2_journal_access_di(handle, INODE_CACHE(local_alloc_inode),
 					 bh, OCFS2_JOURNAL_ACCESS_WRITE);
@@ -1272,13 +1271,12 @@ static int ocfs2_local_alloc_slide_window(struct ocfs2_super *osb,
 	 * local alloc shutdown won't try to double free main bitmap
 	 * bits. Make a copy so the sync function knows which bits to
 	 * free. */
-	alloc_copy = kmalloc(osb->local_alloc_bh->b_size, GFP_NOFS);
+	alloc_copy = kmemdup(alloc, osb->local_alloc_bh->b_size, GFP_NOFS);
 	if (!alloc_copy) {
 		status = -ENOMEM;
 		mlog_errno(status);
 		goto bail;
 	}
-	memcpy(alloc_copy, alloc, osb->local_alloc_bh->b_size);
 
 	status = ocfs2_journal_access_di(handle,
 					 INODE_CACHE(local_alloc_inode),
-- 
2.11.0