+ zram-take-write-lock-in-wb-limit-store-handlers.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: zram: take write lock in wb limit store handlers
has been added to the -mm mm-unstable branch.  Its filename is
     zram-take-write-lock-in-wb-limit-store-handlers.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-take-write-lock-in-wb-limit-store-handlers.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Sergey Senozhatsky <senozhatsky@chromium.org>
Subject: zram: take write lock in wb limit store handlers
Date: Tue, 18 Nov 2025 16:29:57 +0900

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

Link: https://lkml.kernel.org/r/20251118073000.1928107-4-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Richard Chang <richardycc@google.com>
Cc: Yuwen Chen <ywen.chen@foxmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/block/zram/zram_drv.c |   17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

--- a/drivers/block/zram/zram_drv.c~zram-take-write-lock-in-wb-limit-store-handlers
+++ a/drivers/block/zram/zram_drv.c
@@ -519,7 +519,8 @@ struct zram_wb_req {
 };
 
 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;
@@ -528,18 +529,19 @@ static ssize_t writeback_limit_enable_st
 	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);
@@ -554,7 +556,8 @@ static ssize_t writeback_limit_enable_sh
 }
 
 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;
@@ -563,11 +566,11 @@ static ssize_t writeback_limit_store(str
 	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;
_

Patches currently in -mm which might be from senozhatsky@chromium.org are

zram-add-writeback-batch-size-device-attr.patch
zram-take-write-lock-in-wb-limit-store-handlers.patch
zram-drop-wb_limit_lock.patch
zram-rework-bdev-block-allocation.patch
zram-read-slot-block-idx-under-slot-lock.patch