From patchwork Tue Mar 8 05:51:53 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 549618 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 4F91CC433EF for ; Tue, 8 Mar 2022 05:52:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344378AbiCHFxg (ORCPT ); Tue, 8 Mar 2022 00:53:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47668 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343782AbiCHFxe (ORCPT ); Tue, 8 Mar 2022 00:53:34 -0500 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 14BDBD7F; Mon, 7 Mar 2022 21:52:25 -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=gE6pOLmsfSp3ZRv8RixKxwhCbuvenlNJg6rpkeQQsVM=; b=AFnRXTQzI0EfNaZw9q4XGbehjE UIzSMH5XdPW3yd1SMGXizYWEU3ywhiEEvIbUva2LOZAy0pfH5GUIjWj7PKxxWxGh/5Y4JWy7Myf1l eJA8ld+cUyw9z+oMuuvRGUgJzdqNU1hr9gwR8egZmbrkEGFr+iQ8nYqB62i2bRlc/z6LkGNqohLt9 NXd3E4afOZ/l/SOvOrpGhj+EOUyiPSBBJKfGIhuMlF4FZfF1LrprlLB7OmxV3H6H2LvDr5Ob37UAo OeT5MNWyMzNt4aecieTq+MGRx5B1nGPM5VWCD1WUJ8JYB9X2RTSkySDdp5ZcxzxUjxeC7DeKaB9Gx iWiPrAjw==; Received: from [2001:4bb8:184:7746:6f50:7a98:3141:c37b] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1nRSlf-002ioY-Px; Tue, 08 Mar 2022 05:52:20 +0000 From: Christoph Hellwig To: Jens Axboe Cc: "Martin K. Petersen" , Ming Lei , Bart Van Assche , linux-block@vger.kernel.org, linux-scsi@vger.kernel.org Subject: [PATCH 07/14] sd: implement ->free_disk to simplify refcounting Date: Tue, 8 Mar 2022 06:51:53 +0100 Message-Id: <20220308055200.735835-8-hch@lst.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220308055200.735835-1-hch@lst.de> References: <20220308055200.735835-1-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-scsi@vger.kernel.org Implement the ->free_disk method to to put struct scsi_disk when the last gendisk reference count goes away. This removes the need to clear ->private_data and thus freeze the queue on unbind. Signed-off-by: Christoph Hellwig Reviewed-by: Ming Lei Reviewed-by: Martin K. Petersen Reviewed-by: Bart Van Assche --- drivers/scsi/sd.c | 90 +++++++++-------------------------------------- 1 file changed, 16 insertions(+), 74 deletions(-) diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 346b8d62de7d1..73e6f5f0f37c2 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -121,11 +121,6 @@ static void scsi_disk_release(struct device *cdev); static DEFINE_IDA(sd_index_ida); -/* This semaphore is used to mediate the 0->1 reference get in the - * face of object destruction (i.e. we can't allow a get on an - * object after last put) */ -static DEFINE_MUTEX(sd_ref_mutex); - static struct kmem_cache *sd_cdb_cache; static mempool_t *sd_cdb_pool; static mempool_t *sd_page_pool; @@ -663,33 +658,6 @@ static int sd_major(int major_idx) } } -static struct scsi_disk *scsi_disk_get(struct gendisk *disk) -{ - struct scsi_disk *sdkp = NULL; - - mutex_lock(&sd_ref_mutex); - - if (disk->private_data) { - sdkp = scsi_disk(disk); - if (scsi_device_get(sdkp->device) == 0) - get_device(&sdkp->disk_dev); - else - sdkp = NULL; - } - mutex_unlock(&sd_ref_mutex); - return sdkp; -} - -static void scsi_disk_put(struct scsi_disk *sdkp) -{ - struct scsi_device *sdev = sdkp->device; - - mutex_lock(&sd_ref_mutex); - put_device(&sdkp->disk_dev); - scsi_device_put(sdev); - mutex_unlock(&sd_ref_mutex); -} - #ifdef CONFIG_BLK_SED_OPAL static int sd_sec_submit(void *data, u16 spsp, u8 secp, void *buffer, size_t len, bool send) @@ -1418,17 +1386,15 @@ static bool sd_need_revalidate(struct block_device *bdev, **/ static int sd_open(struct block_device *bdev, fmode_t mode) { - struct scsi_disk *sdkp = scsi_disk_get(bdev->bd_disk); - struct scsi_device *sdev; + struct scsi_disk *sdkp = scsi_disk(bdev->bd_disk); + struct scsi_device *sdev = sdkp->device; int retval; - if (!sdkp) + if (scsi_device_get(sdev)) return -ENXIO; SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_open\n")); - sdev = sdkp->device; - /* * If the device is in error recovery, wait until it is done. * If the device is offline, then disallow any access to it. @@ -1473,7 +1439,7 @@ static int sd_open(struct block_device *bdev, fmode_t mode) return 0; error_out: - scsi_disk_put(sdkp); + scsi_device_put(sdev); return retval; } @@ -1502,7 +1468,7 @@ static void sd_release(struct gendisk *disk, fmode_t mode) scsi_set_medium_removal(sdev, SCSI_REMOVAL_ALLOW); } - scsi_disk_put(sdkp); + scsi_device_put(sdev); } static int sd_getgeo(struct block_device *bdev, struct hd_geometry *geo) @@ -1616,7 +1582,7 @@ static int media_not_present(struct scsi_disk *sdkp, **/ static unsigned int sd_check_events(struct gendisk *disk, unsigned int clearing) { - struct scsi_disk *sdkp = scsi_disk_get(disk); + struct scsi_disk *sdkp = disk->private_data; struct scsi_device *sdp; int retval; bool disk_changed; @@ -1679,7 +1645,6 @@ static unsigned int sd_check_events(struct gendisk *disk, unsigned int clearing) */ disk_changed = sdp->changed; sdp->changed = 0; - scsi_disk_put(sdkp); return disk_changed ? DISK_EVENT_MEDIA_CHANGE : 0; } @@ -1887,6 +1852,13 @@ static const struct pr_ops sd_pr_ops = { .pr_clear = sd_pr_clear, }; +static void scsi_disk_free_disk(struct gendisk *disk) +{ + struct scsi_disk *sdkp = scsi_disk(disk); + + put_device(&sdkp->disk_dev); +} + static const struct block_device_operations sd_fops = { .owner = THIS_MODULE, .open = sd_open, @@ -1898,6 +1870,7 @@ static const struct block_device_operations sd_fops = { .unlock_native_capacity = sd_unlock_native_capacity, .report_zones = sd_zbc_report_zones, .get_unique_id = sd_get_unique_id, + .free_disk = scsi_disk_free_disk, .pr_ops = &sd_pr_ops, }; @@ -3623,54 +3596,23 @@ static int sd_probe(struct device *dev) **/ static int sd_remove(struct device *dev) { - struct scsi_disk *sdkp; + struct scsi_disk *sdkp = dev_get_drvdata(dev); - sdkp = dev_get_drvdata(dev); scsi_autopm_get_device(sdkp->device); device_del(&sdkp->disk_dev); del_gendisk(sdkp->disk); sd_shutdown(dev); - mutex_lock(&sd_ref_mutex); - dev_set_drvdata(dev, NULL); - put_device(&sdkp->disk_dev); - mutex_unlock(&sd_ref_mutex); - + put_disk(sdkp->disk); return 0; } -/** - * scsi_disk_release - Called to free the scsi_disk structure - * @dev: pointer to embedded class device - * - * sd_ref_mutex must be held entering this routine. Because it is - * called on last put, you should always use the scsi_disk_get() - * scsi_disk_put() helpers which manipulate the semaphore directly - * and never do a direct put_device. - **/ static void scsi_disk_release(struct device *dev) { struct scsi_disk *sdkp = to_scsi_disk(dev); - struct gendisk *disk = sdkp->disk; - struct request_queue *q = disk->queue; ida_free(&sd_index_ida, sdkp->index); - - /* - * Wait until all requests that are in progress have completed. - * This is necessary to avoid that e.g. scsi_end_request() crashes - * due to clearing the disk->private_data pointer. Wait from inside - * scsi_disk_release() instead of from sd_release() to avoid that - * freezing and unfreezing the request queue affects user space I/O - * in case multiple processes open a /dev/sd... node concurrently. - */ - blk_mq_freeze_queue(q); - blk_mq_unfreeze_queue(q); - - disk->private_data = NULL; - put_disk(disk); - sd_zbc_release_disk(sdkp); put_device(&sdkp->device->sdev_gendev); free_opal_dev(sdkp->opal_dev);