linux-kernel - [PATCH 6/6] iomap: drop unnecessary state

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Message-Id: <20240731091305.2896873-7-yi.zhang@huaweicloud.com>
Date: Wed, 31 Jul 2024 17:13:05 +0800
From: Zhang Yi <yi.zhang@...weicloud.com>
To: linux-xfs@...r.kernel.org,
	linux-fsdevel@...r.kernel.org
Cc: linux-kernel@...r.kernel.org,
	djwong@...nel.org,
	hch@...radead.org,
	brauner@...nel.org,
	david@...morbit.com,
	jack@...e.cz,
	yi.zhang@...wei.com,
	yi.zhang@...weicloud.com,
	chengzhihao1@...wei.com,
	yukuai3@...wei.com
Subject: [PATCH 6/6] iomap: drop unnecessary state_lock when changing ifs dirty bits

From: Zhang Yi <yi.zhang@...wei.com>

Hold the state_lock when set and clear ifs dirty bits is unnecessary
since both paths are protected under folio lock, so it's safe to drop
the state_lock, which could reduce some unnecessary locking overhead and
improve the buffer write performance a bit.

Signed-off-by: Zhang Yi <yi.zhang@...wei.com>
---
 fs/iomap/buffered-io.c | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 248f4a586f8f..22ce6062cfd1 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -137,14 +137,8 @@ static void ifs_clear_range_dirty(struct folio *folio,
 	unsigned int first_blk = DIV_ROUND_UP(off, i_blocksize(inode));
 	unsigned int last_blk = (off + len) >> inode->i_blkbits;
 	unsigned int nr_blks = last_blk - first_blk;
-	unsigned long flags;
 
-	if (!nr_blks)
-		return;
-
-	spin_lock_irqsave(&ifs->state_lock, flags);
 	bitmap_clear(ifs->state, first_blk + blks_per_folio, nr_blks);
-	spin_unlock_irqrestore(&ifs->state_lock, flags);
 }
 
 static void iomap_clear_range_dirty(struct folio *folio, size_t off, size_t len)
@@ -163,11 +157,8 @@ static void ifs_set_range_dirty(struct folio *folio,
 	unsigned int first_blk = (off >> inode->i_blkbits);
 	unsigned int last_blk = (off + len - 1) >> inode->i_blkbits;
 	unsigned int nr_blks = last_blk - first_blk + 1;
-	unsigned long flags;
 
-	spin_lock_irqsave(&ifs->state_lock, flags);
 	bitmap_set(ifs->state, first_blk + blks_per_folio, nr_blks);
-	spin_unlock_irqrestore(&ifs->state_lock, flags);
 }
 
 static void iomap_set_range_dirty(struct folio *folio, size_t off, size_t len)
-- 
2.39.2