From patchwork Tue Nov 24 13:27:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 11928823 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 84477C63798 for ; Tue, 24 Nov 2020 13:28:26 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F08C52083E for ; Tue, 24 Nov 2020 13:28:25 +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="voamq2gI" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F08C52083E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2E9AA6B00D1; Tue, 24 Nov 2020 08:28:25 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 246E76B00D2; Tue, 24 Nov 2020 08:28:25 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 070596B00D3; Tue, 24 Nov 2020 08:28:24 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0235.hostedemail.com [216.40.44.235]) by kanga.kvack.org (Postfix) with ESMTP id D6F0F6B00D1 for ; Tue, 24 Nov 2020 08:28:24 -0500 (EST) Received: from smtpin06.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 9E089181AEF1D for ; Tue, 24 Nov 2020 13:28:24 +0000 (UTC) X-FDA: 77519390928.06.scene58_110384d2736e Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin06.hostedemail.com (Postfix) with ESMTP id 7958210040F10 for ; Tue, 24 Nov 2020 13:28:24 +0000 (UTC) X-HE-Tag: scene58_110384d2736e X-Filterd-Recvd-Size: 5904 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf50.hostedemail.com (Postfix) with ESMTP for ; Tue, 24 Nov 2020 13:28:23 +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=kUYn0sikpHZNYDnsxFrAwXSb49C5P7DMdxps0LhhPGQ=; b=voamq2gIRabU8afAKL3jTQT86w 3voeMXKzWRc968NV3Og6QI7vPIsFgyzT+g3y7G5VN1mzlkrcmMY4Qg7EwhHhprBp2pFWLMjK63ObP R7mWTCNSKQkV5l0bX4rfRh4gKPGZnVeHwjNUcB1zJgqL93wnbxgFlTDmJRPjnCaFhMh+HPucQfU+S uovUuXHghcRdZOgSkakX0fZ9XuPs/BxiQ7jD+ibvnUIkvCuGFLC0BxmxD5xKdEPhugucjYN8I4Xpv WSH12/wojKPamwwzSgge7VqR4tsSr5bVtW0y1gEbh0LGN1fc0aleWXDqaFKriKv0dnauuuFj6BOkD RzQOH7Hw==; Received: from [2001:4bb8:180:5443:c70:4a89:bc61:3] (helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1khYMV-0006Ut-HC; Tue, 24 Nov 2020 13:28:03 +0000 From: Christoph Hellwig To: Jens Axboe Cc: Tejun Heo , Josef Bacik , Konrad Rzeszutek Wilk , Coly Li , Mike Snitzer , Greg Kroah-Hartman , Jan Kara , Johannes Thumshirn , dm-devel@redhat.com, Richard Weinberger , Jan Kara , linux-block@vger.kernel.org, xen-devel@lists.xenproject.org, linux-bcache@vger.kernel.org, linux-mtd@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 06/45] zram: remove the claim mechanism Date: Tue, 24 Nov 2020 14:27:12 +0100 Message-Id: <20201124132751.3747337-7-hch@lst.de> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201124132751.3747337-1-hch@lst.de> References: <20201124132751.3747337-1-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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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 --- drivers/block/zram/zram_drv.c | 72 ++++++++--------------------------- 1 file changed, 15 insertions(+), 57 deletions(-) diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 6d15d51cee2b7e..2e6d75ec1afddb 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 @@ -1974,32 +1942,22 @@ static int zram_add(void) static int zram_remove(struct zram *zram) { - struct block_device *bdev; - - bdev = bdget_disk(zram->disk, 0); - if (!bdev) - return -ENOMEM; + struct block_device *bdev = bdget_disk(zram->disk, 0); - mutex_lock(&bdev->bd_mutex); - if (bdev->bd_openers || zram->claim) { - mutex_unlock(&bdev->bd_mutex); + if (bdev) { + if (bdev->bd_openers) { + bdput(bdev); + return -EBUSY; + } bdput(bdev); - return -EBUSY; } - zram->claim = true; - mutex_unlock(&bdev->bd_mutex); - + del_gendisk(zram->disk); zram_debugfs_unregister(zram); - - /* Make sure all the pending I/O are finished */ - fsync_bdev(bdev); 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);