linux-ext4 - [PATCH v2 5/9] jbd2: remove unneeded kmap to do escape in jbd2_journal_write_metadata

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Date: Tue, 14 May 2024 19:24:34 +0800
From: Kemeng Shi <shikemeng@...weicloud.com>
To: tytso@....edu,
	jack@...e.com,
	yi.zhang@...weicloud.com
Cc: linux-ext4@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2 5/9] jbd2: remove unneeded kmap to do escape in jbd2_journal_write_metadata_buffer

The data to do escape could be accessed directly from b_frozen_data,
just remove unneeded kmap.

Signed-off-by: Kemeng Shi <shikemeng@...weicloud.com>
Reviewed-by: Zhang Yi <yi.zhang@...wei.com>
Reviewed-by: Jan Kara <jack@...e.cz>
---
 fs/jbd2/journal.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 5fb5062cf7ae..c98c06f3113a 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -419,12 +419,11 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
 	/*
 	 * Did we need to do an escaping?  Now we've done all the
 	 * copying, we can finally do so.
+	 * b_frozen_data is from jbd2_alloc() which always provides an
+	 * address from the direct kernels mapping.
 	 */
-	if (do_escape) {
-		mapped_data = kmap_local_folio(new_folio, new_offset);
-		*((unsigned int *)mapped_data) = 0;
-		kunmap_local(mapped_data);
-	}
+	if (do_escape)
+		*((unsigned int *)jh_in->b_frozen_data) = 0;
 
 	folio_set_bh(new_bh, new_folio, new_offset);
 	new_bh->b_size = bh_in->b_size;
-- 
2.30.0