From patchwork Mon Nov 16 14:57:51 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 11909513 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 88ACB697 for ; Mon, 16 Nov 2020 15:11:40 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 42E49206B7 for ; Mon, 16 Nov 2020 15:11:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="um2QX1aP" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 42E49206B7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.28211.57203 (Exim 4.92) (envelope-from ) id 1keg9q-0004vO-Cc; Mon, 16 Nov 2020 15:11:06 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 28211.57203; Mon, 16 Nov 2020 15:11:06 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1keg9o-0004tB-PO; Mon, 16 Nov 2020 15:11:04 +0000 Received: by outflank-mailman (input) for mailman id 28211; Mon, 16 Nov 2020 15:11:01 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1keg34-0006ni-Ag for xen-devel@lists.xenproject.org; Mon, 16 Nov 2020 15:04:06 +0000 Received: from casper.infradead.org (unknown [2001:8b0:10b:1236::1]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 1d91a229-e416-462e-a685-7197268de26f; Mon, 16 Nov 2020 14:59:48 +0000 (UTC) Received: from [2001:4bb8:180:6600:255b:7def:a93:4a09] (helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kefyi-0004Ad-Px; Mon, 16 Nov 2020 14:59:37 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1keg34-0006ni-Ag for xen-devel@lists.xenproject.org; Mon, 16 Nov 2020 15:04:06 +0000 X-Inumbo-ID: 1d91a229-e416-462e-a685-7197268de26f Received: from casper.infradead.org (unknown [2001:8b0:10b:1236::1]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 1d91a229-e416-462e-a685-7197268de26f; Mon, 16 Nov 2020 14:59:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=MmPwn4ttbQT6DHYheoE0UJGEFNI8kA6nAc7IEYdL0K0=; b=um2QX1aPNEBrXGLXtU6YvAtfko SUJQ/zrYAfsNYMAKdZ3tINvi3zqorS3Hcvwis/lRWwGYc/D4a1i+axMJb3c9L3kCaZuM/YpRBYYYl XLZ6DdJ1Y/xHMe+0KQ4YHMrkyZmtkiCaiO6dicUKCBonmuuw50C1TKzUDzndp/SXSYZ/wTEjCmw8k AIxOkUDjtUH52YVU8pqQr/5UXUu1+KzSvrDq39iKullr+3CXYrM5D1wNrkUadnpJVHhZ7zw3XpmrF j8SHOcAIOQu8AyneX2JJ5GEkPZOzCGTSxW+MHMHVW+E/mdPaslbb69OAjiZZeO+aj/n9AezJ3u1Wq K2n33VVw==; Received: from [2001:4bb8:180:6600:255b:7def:a93:4a09] (helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kefyi-0004Ad-Px; Mon, 16 Nov 2020 14:59:37 +0000 From: Christoph Hellwig To: Jens Axboe Cc: Justin Sanders , Josef Bacik , Ilya Dryomov , Jack Wang , "Michael S. Tsirkin" , Jason Wang , Paolo Bonzini , Stefan Hajnoczi , Konrad Rzeszutek Wilk , =?utf-8?q?Roger_Pau_Monn?= =?utf-8?q?=C3=A9?= , Minchan Kim , Mike Snitzer , Song Liu , "Martin K. Petersen" , dm-devel@redhat.com, linux-block@vger.kernel.org, drbd-dev@lists.linbit.com, nbd@other.debian.org, ceph-devel@vger.kernel.org, xen-devel@lists.xenproject.org, linux-raid@vger.kernel.org, linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH 60/78] zram: remove the claim mechanism Date: Mon, 16 Nov 2020 15:57:51 +0100 Message-Id: <20201116145809.410558-61-hch@lst.de> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201116145809.410558-1-hch@lst.de> References: <20201116145809.410558-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html The zram claim mechanism was added to ensure no new opens come in during teardown. But the proper way to archive that is to call del_gendisk first, which takes care of all that. Once del_gendisk is called in the right place, the reset side can also be simplified as no I/O can be outstanding on a block device that is not open. Signed-off-by: Christoph Hellwig Reviewed-by: Hannes Reinecke --- drivers/block/zram/zram_drv.c | 76 ++++++++++------------------------- 1 file changed, 21 insertions(+), 55 deletions(-) diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 6d15d51cee2b7e..3641434a9b154d 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -1756,64 +1756,33 @@ static ssize_t disksize_store(struct device *dev, static ssize_t reset_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t len) { - int ret; - unsigned short do_reset; - struct zram *zram; + struct zram *zram = dev_to_zram(dev); struct block_device *bdev; + unsigned short do_reset; + int ret = 0; ret = kstrtou16(buf, 10, &do_reset); if (ret) return ret; - if (!do_reset) return -EINVAL; - zram = dev_to_zram(dev); bdev = bdget_disk(zram->disk, 0); if (!bdev) return -ENOMEM; mutex_lock(&bdev->bd_mutex); - /* Do not reset an active device or claimed device */ - if (bdev->bd_openers || zram->claim) { - mutex_unlock(&bdev->bd_mutex); - bdput(bdev); - return -EBUSY; - } - - /* From now on, anyone can't open /dev/zram[0-9] */ - zram->claim = true; + if (bdev->bd_openers) + ret = -EBUSY; + else + zram_reset_device(zram); mutex_unlock(&bdev->bd_mutex); - - /* Make sure all the pending I/O are finished */ - fsync_bdev(bdev); - zram_reset_device(zram); bdput(bdev); - mutex_lock(&bdev->bd_mutex); - zram->claim = false; - mutex_unlock(&bdev->bd_mutex); - - return len; -} - -static int zram_open(struct block_device *bdev, fmode_t mode) -{ - int ret = 0; - struct zram *zram; - - WARN_ON(!mutex_is_locked(&bdev->bd_mutex)); - - zram = bdev->bd_disk->private_data; - /* zram was claimed to reset so open request fails */ - if (zram->claim) - ret = -EBUSY; - - return ret; + return ret ? ret : len; } static const struct block_device_operations zram_devops = { - .open = zram_open, .submit_bio = zram_submit_bio, .swap_slot_free_notify = zram_slot_free_notify, .rw_page = zram_rw_page, @@ -1821,7 +1790,6 @@ static const struct block_device_operations zram_devops = { }; static const struct block_device_operations zram_wb_devops = { - .open = zram_open, .submit_bio = zram_submit_bio, .swap_slot_free_notify = zram_slot_free_notify, .owner = THIS_MODULE @@ -1972,34 +1940,32 @@ static int zram_add(void) return ret; } -static int zram_remove(struct zram *zram) +static bool zram_busy(struct zram *zram) { struct block_device *bdev; + bool busy = false; bdev = bdget_disk(zram->disk, 0); - if (!bdev) - return -ENOMEM; - - mutex_lock(&bdev->bd_mutex); - if (bdev->bd_openers || zram->claim) { - mutex_unlock(&bdev->bd_mutex); + if (bdev) { + if (bdev->bd_openers) + busy = true; bdput(bdev); - return -EBUSY; } - zram->claim = true; - mutex_unlock(&bdev->bd_mutex); + return busy; +} - zram_debugfs_unregister(zram); +static int zram_remove(struct zram *zram) +{ + if (zram_busy(zram)) + return -EBUSY; - /* Make sure all the pending I/O are finished */ - fsync_bdev(bdev); + del_gendisk(zram->disk); + zram_debugfs_unregister(zram); zram_reset_device(zram); - bdput(bdev); pr_info("Removed device: %s\n", zram->disk->disk_name); - del_gendisk(zram->disk); blk_cleanup_queue(zram->disk->queue); put_disk(zram->disk); kfree(zram);