linux-kernel - [PATCHv2 3/4] zram: take write lock in wb limit store handlers

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Message-ID: <20251113085402.1811522-4-senozhatsky@chromium.org>
Date: Thu, 13 Nov 2025 17:54:01 +0900
From: Sergey Senozhatsky <senozhatsky@...omium.org>
To: Andrew Morton <akpm@...ux-foundation.org>,
	Minchan Kim <minchan@...nel.org>,
	Yuwen Chen <ywen.chen@...mail.com>,
	Richard Chang <richardycc@...gle.com>
Cc: Brian Geffon <bgeffon@...gle.com>,
	Fengyu Lian <licayy@...look.com>,
	linux-kernel@...r.kernel.org,
	linux-mm@...ck.org,
	linux-block@...r.kernel.org,
	Sergey Senozhatsky <senozhatsky@...omium.org>
Subject: [PATCHv2 3/4] zram: take write lock in wb limit store handlers

Write device attrs handlers should take write zram init_lock.
While at it, fixup coding styles.

Signed-off-by: Sergey Senozhatsky <senozhatsky@...omium.org>
---
 drivers/block/zram/zram_drv.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 238b997f6891..6312b0437618 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -501,7 +501,8 @@ static ssize_t idle_store(struct device *dev,
 
 #ifdef CONFIG_ZRAM_WRITEBACK
 static ssize_t writeback_limit_enable_store(struct device *dev,
-		struct device_attribute *attr, const char *buf, size_t len)
+					    struct device_attribute *attr,
+					    const char *buf, size_t len)
 {
 	struct zram *zram = dev_to_zram(dev);
 	u64 val;
@@ -510,18 +511,19 @@ static ssize_t writeback_limit_enable_store(struct device *dev,
 	if (kstrtoull(buf, 10, &val))
 		return ret;
 
-	down_read(&zram->init_lock);
+	down_write(&zram->init_lock);
 	spin_lock(&zram->wb_limit_lock);
 	zram->wb_limit_enable = val;
 	spin_unlock(&zram->wb_limit_lock);
-	up_read(&zram->init_lock);
+	up_write(&zram->init_lock);
 	ret = len;
 
 	return ret;
 }
 
 static ssize_t writeback_limit_enable_show(struct device *dev,
-		struct device_attribute *attr, char *buf)
+					   struct device_attribute *attr,
+					   char *buf)
 {
 	bool val;
 	struct zram *zram = dev_to_zram(dev);
@@ -536,7 +538,8 @@ static ssize_t writeback_limit_enable_show(struct device *dev,
 }
 
 static ssize_t writeback_limit_store(struct device *dev,
-		struct device_attribute *attr, const char *buf, size_t len)
+				     struct device_attribute *attr,
+				     const char *buf, size_t len)
 {
 	struct zram *zram = dev_to_zram(dev);
 	u64 val;
@@ -545,11 +548,11 @@ static ssize_t writeback_limit_store(struct device *dev,
 	if (kstrtoull(buf, 10, &val))
 		return ret;
 
-	down_read(&zram->init_lock);
+	down_write(&zram->init_lock);
 	spin_lock(&zram->wb_limit_lock);
 	zram->bd_wb_limit = val;
 	spin_unlock(&zram->wb_limit_lock);
-	up_read(&zram->init_lock);
+	up_write(&zram->init_lock);
 	ret = len;
 
 	return ret;
-- 
2.51.2.1041.gc1ab5b90ca-goog