From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D59414E80CD for ; Fri, 4 Sep 2026 20:32:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788553942; cv=none; b=W8EgH4IZKyrb8EVJEnw5tavSt6efm9ksxXwnDAc2SkNrM+FQBZjjh6b1bIbRodBrPJQjNlu++pzfo5Dn5hhHLw0KEMGYv7f8hG8VJW89xaJP2LKlQINBptLwThXZmKph33nSNyHtFmgZaTuMiTtQjhw1PVJzaJKj4Unr61l6rlk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788553942; c=relaxed/simple; bh=MPtPmYz0UQE2CLr3GsSxVgdEE321YCUk934Fd4v1BC8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=iINsiMN2p/zbnkx6j/svy1nCps1XydfTD1f3wHeO1y4gDm7Z+J/QGA7VB0Vk1HTptjrgeHKv7A0y7d2Afgor+YAw/4o1LaFwUUKNCWYYvb3ZhZMHfD5XsNGuWZrm94EXkJ2McrX7FWLa/x3BEs3bGWBYcGDkkN4oE0y1vEzUDHE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gnIx0Alm; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gnIx0Alm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 33C3E1F00ACA; Fri, 4 Sep 2026 20:32:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788553935; bh=86PB7/2JzUS/3xqeXQuq+V86iBSVuEuol06ePYZwgzg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=gnIx0AlmV/BaD3j/aosnPkcQkFCcYrhgMnh0l/G7G70edMwz4I2bNWCSp0RJXag+r GWEaHkDyxMgfNmZ/tqzXHHYYGfjWht89TnW8LqhYr9EtZ9eXWyZ2cwD+sNYZIX1FI2 fJT7hIEtBMFJu02O0ZJQqeLLr/sBLEiSi1WrrNLiBeyFNDcvSP2V/dnjtdhRcZMOCp lDy5N2u2x51een1ypUrCmTBDEjUX6e1iauWLYnu79wMQrKnKt0S2psOFQJgHWrRe/h zYvqQ8SHVWBiJDZkvN0YAXLldf+mXupRevLmkRmt1Ya1aB9p84P5mVtO9ejKFBxhqL 1jDy8BMiHuDUQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Sergey Senozhatsky , Brian Geffon , Minchan Kim , Richard Chang , Yuwen Chen , Andrew Morton , Sasha Levin Subject: [PATCH 6.18.y 2/5] zram: drop wb_limit_lock Date: Fri, 4 Sep 2026 16:32:08 -0400 Message-ID: <20260904203211.1547892-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260904203211.1547892-1-sashal@kernel.org> References: <2026090323-dreamboat-stable-993d@gregkh> <20260904203211.1547892-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Sergey Senozhatsky [ Upstream commit a4f506c569e1320c2db4a32955e47961fcf02b05 ] We don't need wb_limit_lock. Writeback limit setters take an exclusive write zram init_lock, while wb_limit modifications happen only from a single task and under zram read init_lock. No concurrent wb_limit modifications are possible (we permit only one post-processing task at a time). Add lockdep assertions to wb_limit mutators. While at it, fixup coding styles. Link: https://lkml.kernel.org/r/20251122074029.3948921-5-senozhatsky@chromium.org Signed-off-by: Sergey Senozhatsky Reviewed-by: Brian Geffon Cc: Minchan Kim Cc: Richard Chang Cc: Yuwen Chen Signed-off-by: Andrew Morton Stable-dep-of: dde75313eed0 ("zram: set default primary compressor in zram_destroy_comps()") Signed-off-by: Sasha Levin --- drivers/block/zram/zram_drv.c | 23 ++++------------------- drivers/block/zram/zram_drv.h | 1 - 2 files changed, 4 insertions(+), 20 deletions(-) diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 1f0727c0b1748..a9f69da092ba5 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -512,9 +512,7 @@ static ssize_t writeback_limit_enable_store(struct device *dev, return ret; down_write(&zram->init_lock); - spin_lock(&zram->wb_limit_lock); zram->wb_limit_enable = val; - spin_unlock(&zram->wb_limit_lock); up_write(&zram->init_lock); ret = len; @@ -529,9 +527,7 @@ static ssize_t writeback_limit_enable_show(struct device *dev, struct zram *zram = dev_to_zram(dev); down_read(&zram->init_lock); - spin_lock(&zram->wb_limit_lock); val = zram->wb_limit_enable; - spin_unlock(&zram->wb_limit_lock); up_read(&zram->init_lock); return sysfs_emit(buf, "%d\n", val); @@ -549,9 +545,7 @@ static ssize_t writeback_limit_store(struct device *dev, return ret; down_write(&zram->init_lock); - spin_lock(&zram->wb_limit_lock); zram->bd_wb_limit = val; - spin_unlock(&zram->wb_limit_lock); up_write(&zram->init_lock); ret = len; @@ -559,15 +553,13 @@ static ssize_t writeback_limit_store(struct device *dev, } static ssize_t writeback_limit_show(struct device *dev, - struct device_attribute *attr, char *buf) + struct device_attribute *attr, char *buf) { u64 val; struct zram *zram = dev_to_zram(dev); down_read(&zram->init_lock); - spin_lock(&zram->wb_limit_lock); val = zram->bd_wb_limit; - spin_unlock(&zram->wb_limit_lock); up_read(&zram->init_lock); return sysfs_emit(buf, "%llu\n", val); @@ -747,18 +739,17 @@ static int zram_writeback_slots(struct zram *zram, struct zram_pp_ctl *ctl) int ret = 0, err; u32 index; + lockdep_assert_held_read(&zram->init_lock); + page = alloc_page(GFP_KERNEL); if (!page) return -ENOMEM; while ((pps = select_pp_slot(ctl))) { - spin_lock(&zram->wb_limit_lock); if (zram->wb_limit_enable && !zram->bd_wb_limit) { - spin_unlock(&zram->wb_limit_lock); ret = -EIO; break; } - spin_unlock(&zram->wb_limit_lock); if (!blk_idx) { blk_idx = alloc_block_bdev(zram); @@ -824,10 +815,8 @@ static int zram_writeback_slots(struct zram *zram, struct zram_pp_ctl *ctl) zram_set_handle(zram, index, blk_idx); blk_idx = 0; atomic64_inc(&zram->stats.pages_stored); - spin_lock(&zram->wb_limit_lock); if (zram->wb_limit_enable && zram->bd_wb_limit > 0) zram->bd_wb_limit -= 1UL << (PAGE_SHIFT - 12); - spin_unlock(&zram->wb_limit_lock); next: zram_slot_unlock(zram, index); release_pp_slot(zram, pps); @@ -2467,7 +2456,7 @@ static void zram_destroy_comps(struct zram *zram) static void zram_reset_device(struct zram *zram) { - down_write(&zram->init_lock); + guard(rwsem_write)(&zram->init_lock); zram->limit_pages = 0; @@ -2483,7 +2472,6 @@ static void zram_reset_device(struct zram *zram) reset_bdev(zram); comp_algorithm_set(zram, ZRAM_PRIMARY_COMP, default_compressor); - up_write(&zram->init_lock); } static ssize_t disksize_store(struct device *dev, @@ -2695,9 +2683,6 @@ static int zram_add(void) device_id = ret; init_rwsem(&zram->init_lock); -#ifdef CONFIG_ZRAM_WRITEBACK - spin_lock_init(&zram->wb_limit_lock); -#endif /* gendisk structure */ zram->disk = blk_alloc_disk(&lim, NUMA_NO_NODE); diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h index 6cee93f9c0d06..8f64317e3b6c5 100644 --- a/drivers/block/zram/zram_drv.h +++ b/drivers/block/zram/zram_drv.h @@ -127,7 +127,6 @@ struct zram { bool claim; /* Protected by disk->open_mutex */ #ifdef CONFIG_ZRAM_WRITEBACK struct file *backing_dev; - spinlock_t wb_limit_lock; bool wb_limit_enable; u64 bd_wb_limit; struct block_device *bdev; -- 2.53.0