From patchwork Wed Feb 2 15:56:56 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 12733201 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1059CC4332F for ; Wed, 2 Feb 2022 15:57:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230107AbiBBP5V (ORCPT ); Wed, 2 Feb 2022 10:57:21 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34082 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231464AbiBBP5V (ORCPT ); Wed, 2 Feb 2022 10:57:21 -0500 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D8A58C061714; Wed, 2 Feb 2022 07:57:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; 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=RQVNHCatJvLCv4jx0212GllBIGNDJDqNgc8YR9mScqY=; b=IpiTD4qIhHD/DA5jcTUPTNGng+ gqMCPomDR/+3/pDmjAybadeTMpisK+ujX8BNPonSMgMKNaO0SFmhdCaipceWUaUGEbB71JWJWEJ7o lMf51fPkAG37QJxcPcoY3lJaYqAdHAjXD9Wi03AVaiOxNfaPPPGsv5nMITdTLEtDDCSN7vmk6YFiJ yTdwtgIiGjia9GT/Zvcm0UN+9t9Wl8abhUj67xSAcTezn3wUQdoI5QvUZq6ObzefhI8u7E25xIusj ud3j5ZxGBe7Ca6XBMDq6cSE7lU9JPMAjGn4JAE0jGeGuinteO8/khYkY6p3qUY36/t6YlOK9aMwu9 oB0dsBow==; Received: from [2001:4bb8:191:327d:b3e5:1ccd:eaac:6609] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1nFI0K-00G6Xp-8H; Wed, 02 Feb 2022 15:57:09 +0000 From: Christoph Hellwig To: Jens Axboe Cc: "Michael S. Tsirkin" , Jason Wang , Paolo Bonzini , Stefan Hajnoczi , Maxim Levitsky , Alex Dubov , Ulf Hansson , linux-block@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-mmc@vger.kernel.org Subject: [PATCH 2/5] virtio_blk: simplify refcounting Date: Wed, 2 Feb 2022 16:56:56 +0100 Message-Id: <20220202155659.107895-3-hch@lst.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220202155659.107895-1-hch@lst.de> References: <20220202155659.107895-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org Implement the ->free_disk method to free the virtio_blk structure only once the last gendisk reference goes away instead of keeping a local refcount. Signed-off-by: Christoph Hellwig Acked-by: Michael S. Tsirkin --- drivers/block/virtio_blk.c | 64 +++++++------------------------------- 1 file changed, 12 insertions(+), 52 deletions(-) diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index c443cd64fc9b4..2d939ac1508c1 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -69,13 +69,6 @@ struct virtio_blk { /* Process context for config space updates */ struct work_struct config_work; - /* - * Tracks references from block_device_operations open/release and - * virtio_driver probe/remove so this object can be freed once no - * longer in use. - */ - refcount_t refs; - /* What host tells us, plus 2 for header & tailer. */ unsigned int sg_elems; @@ -391,43 +384,6 @@ static int virtblk_get_id(struct gendisk *disk, char *id_str) return err; } -static void virtblk_get(struct virtio_blk *vblk) -{ - refcount_inc(&vblk->refs); -} - -static void virtblk_put(struct virtio_blk *vblk) -{ - if (refcount_dec_and_test(&vblk->refs)) { - ida_simple_remove(&vd_index_ida, vblk->index); - mutex_destroy(&vblk->vdev_mutex); - kfree(vblk); - } -} - -static int virtblk_open(struct block_device *bd, fmode_t mode) -{ - struct virtio_blk *vblk = bd->bd_disk->private_data; - int ret = 0; - - mutex_lock(&vblk->vdev_mutex); - - if (vblk->vdev) - virtblk_get(vblk); - else - ret = -ENXIO; - - mutex_unlock(&vblk->vdev_mutex); - return ret; -} - -static void virtblk_release(struct gendisk *disk, fmode_t mode) -{ - struct virtio_blk *vblk = disk->private_data; - - virtblk_put(vblk); -} - /* We provide getgeo only to please some old bootloader/partitioning tools */ static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo) { @@ -460,11 +416,19 @@ static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo) return ret; } +static void virtblk_free_disk(struct gendisk *disk) +{ + struct virtio_blk *vblk = disk->private_data; + + ida_simple_remove(&vd_index_ida, vblk->index); + mutex_destroy(&vblk->vdev_mutex); + kfree(vblk); +} + static const struct block_device_operations virtblk_fops = { - .owner = THIS_MODULE, - .open = virtblk_open, - .release = virtblk_release, - .getgeo = virtblk_getgeo, + .owner = THIS_MODULE, + .getgeo = virtblk_getgeo, + .free_disk = virtblk_free_disk, }; static int index_to_minor(int index) @@ -791,8 +755,6 @@ static int virtblk_probe(struct virtio_device *vdev) goto out_free_index; } - /* This reference is dropped in virtblk_remove(). */ - refcount_set(&vblk->refs, 1); mutex_init(&vblk->vdev_mutex); vblk->vdev = vdev; @@ -985,8 +947,6 @@ static void virtblk_remove(struct virtio_device *vdev) kfree(vblk->vqs); mutex_unlock(&vblk->vdev_mutex); - - virtblk_put(vblk); } #ifdef CONFIG_PM_SLEEP