From patchwork Mon Aug 13 14:01:10 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?b?SsO8cmdlbiBHcm/Dnw==?= X-Patchwork-Id: 10564267 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5044E13B4 for ; Mon, 13 Aug 2018 14:01:38 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3EBC429288 for ; Mon, 13 Aug 2018 14:01:38 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3261D292AE; Mon, 13 Aug 2018 14:01:38 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 86A8429288 for ; Mon, 13 Aug 2018 14:01:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729937AbeHMQnp (ORCPT ); Mon, 13 Aug 2018 12:43:45 -0400 Received: from mx2.suse.de ([195.135.220.15]:60808 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728514AbeHMQno (ORCPT ); Mon, 13 Aug 2018 12:43:44 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id DFD03AF7E; Mon, 13 Aug 2018 14:01:16 +0000 (UTC) From: Juergen Gross To: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, linux-block@vger.kernel.org Cc: konrad.wilk@oracle.com, roger.pau@citrix.com, axboe@kernel.dk, boris.ostrovsky@oracle.com, Juergen Gross Subject: [PATCH v3 1/5] xen/blkback: don't keep persistent grants too long Date: Mon, 13 Aug 2018 16:01:10 +0200 Message-Id: <20180813140114.20126-2-jgross@suse.com> X-Mailer: git-send-email 2.13.7 In-Reply-To: <20180813140114.20126-1-jgross@suse.com> References: <20180813140114.20126-1-jgross@suse.com> MIME-Version: 1.0 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Persistent grants are allocated until a threshold per ring is being reached. Those grants won't be freed until the ring is being destroyed meaning there will be resources kept busy which might no longer be used. Instead of freeing only persistent grants until the threshold is reached add a timestamp and remove all persistent grants not having been in use for a minute. Signed-off-by: Juergen Gross Reviewed-by: Roger Pau Monné --- V3: make timeout parameter static --- Documentation/ABI/testing/sysfs-driver-xen-blkback | 10 +++ drivers/block/xen-blkback/blkback.c | 88 ++++++++++++---------- drivers/block/xen-blkback/common.h | 8 +- 3 files changed, 60 insertions(+), 46 deletions(-) diff --git a/Documentation/ABI/testing/sysfs-driver-xen-blkback b/Documentation/ABI/testing/sysfs-driver-xen-blkback index 8bb43b66eb55..4e7babb3ba1f 100644 --- a/Documentation/ABI/testing/sysfs-driver-xen-blkback +++ b/Documentation/ABI/testing/sysfs-driver-xen-blkback @@ -15,3 +15,13 @@ Description: blkback. If the frontend tries to use more than max_persistent_grants, the LRU kicks in and starts removing 5% of max_persistent_grants every 100ms. + +What: /sys/module/xen_blkback/parameters/persistent_grant_unused_seconds +Date: August 2018 +KernelVersion: 4.19 +Contact: Roger Pau Monné +Description: + How long a persistent grant is allowed to remain + allocated without being in use. The time is in + seconds, 0 means indefinitely long. + The default is 60 seconds. diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index b55b245e8052..9eae7b243f68 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -84,6 +84,18 @@ MODULE_PARM_DESC(max_persistent_grants, "Maximum number of grants to map persistently"); /* + * How long a persistent grant is allowed to remain allocated without being in + * use. The time is in seconds, 0 means indefinitely long. + */ + +static unsigned int xen_blkif_pgrant_timeout = 60; +module_param_named(persistent_grant_unused_seconds, xen_blkif_pgrant_timeout, + uint, 0644); +MODULE_PARM_DESC(persistent_grant_unused_seconds, + "Time in seconds an unused persistent grant is allowed to " + "remain allocated. Default is 60, 0 means unlimited."); + +/* * Maximum number of rings/queues blkback supports, allow as many queues as there * are CPUs if user has not specified a value. */ @@ -123,6 +135,13 @@ module_param(log_stats, int, 0644); /* Number of free pages to remove on each call to gnttab_free_pages */ #define NUM_BATCH_FREE_PAGES 10 +static inline bool persistent_gnt_timeout(struct persistent_gnt *persistent_gnt) +{ + return xen_blkif_pgrant_timeout && + (jiffies - persistent_gnt->last_used >= + HZ * xen_blkif_pgrant_timeout); +} + static inline int get_free_page(struct xen_blkif_ring *ring, struct page **page) { unsigned long flags; @@ -278,7 +297,7 @@ static void put_persistent_gnt(struct xen_blkif_ring *ring, { if(!test_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags)) pr_alert_ratelimited("freeing a grant already unused\n"); - set_bit(PERSISTENT_GNT_WAS_ACTIVE, persistent_gnt->flags); + persistent_gnt->last_used = jiffies; clear_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags); atomic_dec(&ring->persistent_gnt_in_use); } @@ -371,26 +390,26 @@ static void purge_persistent_gnt(struct xen_blkif_ring *ring) struct persistent_gnt *persistent_gnt; struct rb_node *n; unsigned int num_clean, total; - bool scan_used = false, clean_used = false; + bool scan_used = false; struct rb_root *root; - if (ring->persistent_gnt_c < xen_blkif_max_pgrants || - (ring->persistent_gnt_c == xen_blkif_max_pgrants && - !ring->blkif->vbd.overflow_max_grants)) { - goto out; - } - if (work_busy(&ring->persistent_purge_work)) { pr_alert_ratelimited("Scheduled work from previous purge is still busy, cannot purge list\n"); goto out; } - num_clean = (xen_blkif_max_pgrants / 100) * LRU_PERCENT_CLEAN; - num_clean = ring->persistent_gnt_c - xen_blkif_max_pgrants + num_clean; - num_clean = min(ring->persistent_gnt_c, num_clean); - if ((num_clean == 0) || - (num_clean > (ring->persistent_gnt_c - atomic_read(&ring->persistent_gnt_in_use)))) - goto out; + if (ring->persistent_gnt_c < xen_blkif_max_pgrants || + (ring->persistent_gnt_c == xen_blkif_max_pgrants && + !ring->blkif->vbd.overflow_max_grants)) { + num_clean = 0; + } else { + num_clean = (xen_blkif_max_pgrants / 100) * LRU_PERCENT_CLEAN; + num_clean = ring->persistent_gnt_c - xen_blkif_max_pgrants + + num_clean; + num_clean = min(ring->persistent_gnt_c, num_clean); + pr_debug("Going to purge at least %u persistent grants\n", + num_clean); + } /* * At this point, we can assure that there will be no calls @@ -401,9 +420,7 @@ static void purge_persistent_gnt(struct xen_blkif_ring *ring) * number of grants. */ - total = num_clean; - - pr_debug("Going to purge %u persistent grants\n", num_clean); + total = 0; BUG_ON(!list_empty(&ring->persistent_purge_list)); root = &ring->persistent_gnts; @@ -412,46 +429,37 @@ static void purge_persistent_gnt(struct xen_blkif_ring *ring) BUG_ON(persistent_gnt->handle == BLKBACK_INVALID_HANDLE); - if (clean_used) { - clear_bit(PERSISTENT_GNT_WAS_ACTIVE, persistent_gnt->flags); - continue; - } - if (test_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags)) continue; - if (!scan_used && - (test_bit(PERSISTENT_GNT_WAS_ACTIVE, persistent_gnt->flags))) + if (!scan_used && !persistent_gnt_timeout(persistent_gnt)) + continue; + if (scan_used && total >= num_clean) continue; rb_erase(&persistent_gnt->node, root); list_add(&persistent_gnt->remove_node, &ring->persistent_purge_list); - if (--num_clean == 0) - goto finished; + total++; } /* - * If we get here it means we also need to start cleaning + * Check whether we also need to start cleaning * grants that were used since last purge in order to cope * with the requested num */ - if (!scan_used && !clean_used) { - pr_debug("Still missing %u purged frames\n", num_clean); + if (!scan_used && total < num_clean) { + pr_debug("Still missing %u purged frames\n", num_clean - total); scan_used = true; goto purge_list; } -finished: - if (!clean_used) { - pr_debug("Finished scanning for grants to clean, removing used flag\n"); - clean_used = true; - goto purge_list; - } - ring->persistent_gnt_c -= (total - num_clean); - ring->blkif->vbd.overflow_max_grants = 0; + if (total) { + ring->persistent_gnt_c -= total; + ring->blkif->vbd.overflow_max_grants = 0; - /* We can defer this work */ - schedule_work(&ring->persistent_purge_work); - pr_debug("Purged %u/%u\n", (total - num_clean), total); + /* We can defer this work */ + schedule_work(&ring->persistent_purge_work); + pr_debug("Purged %u/%u\n", num_clean, total); + } out: return; diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h index ecb35fe8ca8d..7bff72db3b7e 100644 --- a/drivers/block/xen-blkback/common.h +++ b/drivers/block/xen-blkback/common.h @@ -234,14 +234,9 @@ struct xen_vbd { struct backend_info; /* Number of available flags */ -#define PERSISTENT_GNT_FLAGS_SIZE 2 +#define PERSISTENT_GNT_FLAGS_SIZE 1 /* This persistent grant is currently in use */ #define PERSISTENT_GNT_ACTIVE 0 -/* - * This persistent grant has been used, this flag is set when we remove the - * PERSISTENT_GNT_ACTIVE, to know that this grant has been used recently. - */ -#define PERSISTENT_GNT_WAS_ACTIVE 1 /* Number of requests that we can fit in a ring */ #define XEN_BLKIF_REQS_PER_PAGE 32 @@ -250,6 +245,7 @@ struct persistent_gnt { struct page *page; grant_ref_t gnt; grant_handle_t handle; + unsigned long last_used; DECLARE_BITMAP(flags, PERSISTENT_GNT_FLAGS_SIZE); struct rb_node node; struct list_head remove_node; From patchwork Mon Aug 13 14:01:11 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?b?SsO8cmdlbiBHcm/Dnw==?= X-Patchwork-Id: 10564271 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8A25D13B4 for ; Mon, 13 Aug 2018 14:01:48 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7ACA229290 for ; Mon, 13 Aug 2018 14:01:48 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6C7FB292A4; Mon, 13 Aug 2018 14:01:48 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E5A1229275 for ; Mon, 13 Aug 2018 14:01:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729864AbeHMQnn (ORCPT ); Mon, 13 Aug 2018 12:43:43 -0400 Received: from mx2.suse.de ([195.135.220.15]:60820 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728557AbeHMQnn (ORCPT ); Mon, 13 Aug 2018 12:43:43 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 1CF62AFA1; Mon, 13 Aug 2018 14:01:17 +0000 (UTC) From: Juergen Gross To: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, linux-block@vger.kernel.org Cc: konrad.wilk@oracle.com, roger.pau@citrix.com, axboe@kernel.dk, boris.ostrovsky@oracle.com, Juergen Gross Subject: [PATCH v3 2/5] xen/blkfront: cleanup stale persistent grants Date: Mon, 13 Aug 2018 16:01:11 +0200 Message-Id: <20180813140114.20126-3-jgross@suse.com> X-Mailer: git-send-email 2.13.7 In-Reply-To: <20180813140114.20126-1-jgross@suse.com> References: <20180813140114.20126-1-jgross@suse.com> MIME-Version: 1.0 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add a periodic cleanup function to remove old persistent grants which are no longer in use on the backend side. This avoids starvation in case there are lots of persistent grants for a device which no longer is involved in I/O business. Signed-off-by: Juergen Gross Reviewed-by: Roger Pau Monné --- drivers/block/xen-blkfront.c | 94 ++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 90 insertions(+), 4 deletions(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index b5cedccb5d7d..7c4b1b9d3971 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -46,6 +46,7 @@ #include #include #include +#include #include #include @@ -121,6 +122,8 @@ static inline struct blkif_req *blkif_req(struct request *rq) static DEFINE_MUTEX(blkfront_mutex); static const struct block_device_operations xlvbd_block_fops; +static struct delayed_work blkfront_work; +static LIST_HEAD(info_list); /* * Maximum number of segments in indirect requests, the actual value used by @@ -216,6 +219,7 @@ struct blkfront_info /* Save uncomplete reqs and bios for migration. */ struct list_head requests; struct bio_list bio_list; + struct list_head info_list; }; static unsigned int nr_minors; @@ -1764,6 +1768,12 @@ static int write_per_ring_nodes(struct xenbus_transaction xbt, return err; } +static void free_info(struct blkfront_info *info) +{ + list_del(&info->info_list); + kfree(info); +} + /* Common code used when first setting up, and when resuming. */ static int talk_to_blkback(struct xenbus_device *dev, struct blkfront_info *info) @@ -1885,7 +1895,10 @@ static int talk_to_blkback(struct xenbus_device *dev, destroy_blkring: blkif_free(info, 0); - kfree(info); + mutex_lock(&blkfront_mutex); + free_info(info); + mutex_unlock(&blkfront_mutex); + dev_set_drvdata(&dev->dev, NULL); return err; @@ -1996,6 +2009,10 @@ static int blkfront_probe(struct xenbus_device *dev, info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0); dev_set_drvdata(&dev->dev, info); + mutex_lock(&blkfront_mutex); + list_add(&info->info_list, &info_list); + mutex_unlock(&blkfront_mutex); + return 0; } @@ -2306,6 +2323,12 @@ static void blkfront_gather_backend_features(struct blkfront_info *info) if (indirect_segments <= BLKIF_MAX_SEGMENTS_PER_REQUEST) indirect_segments = 0; info->max_indirect_segments = indirect_segments; + + if (info->feature_persistent) { + mutex_lock(&blkfront_mutex); + schedule_delayed_work(&blkfront_work, HZ * 10); + mutex_unlock(&blkfront_mutex); + } } /* @@ -2487,7 +2510,9 @@ static int blkfront_remove(struct xenbus_device *xbdev) mutex_unlock(&info->mutex); if (!bdev) { - kfree(info); + mutex_lock(&blkfront_mutex); + free_info(info); + mutex_unlock(&blkfront_mutex); return 0; } @@ -2507,7 +2532,9 @@ static int blkfront_remove(struct xenbus_device *xbdev) if (info && !bdev->bd_openers) { xlvbd_release_gendisk(info); disk->private_data = NULL; - kfree(info); + mutex_lock(&blkfront_mutex); + free_info(info); + mutex_unlock(&blkfront_mutex); } mutex_unlock(&bdev->bd_mutex); @@ -2590,7 +2617,7 @@ static void blkif_release(struct gendisk *disk, fmode_t mode) dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n"); xlvbd_release_gendisk(info); disk->private_data = NULL; - kfree(info); + free_info(info); } out: @@ -2623,6 +2650,61 @@ static struct xenbus_driver blkfront_driver = { .is_ready = blkfront_is_ready, }; +static void purge_persistent_grants(struct blkfront_info *info) +{ + unsigned int i; + unsigned long flags; + + for (i = 0; i < info->nr_rings; i++) { + struct blkfront_ring_info *rinfo = &info->rinfo[i]; + struct grant *gnt_list_entry, *tmp; + + spin_lock_irqsave(&rinfo->ring_lock, flags); + + if (rinfo->persistent_gnts_c == 0) { + spin_unlock_irqrestore(&rinfo->ring_lock, flags); + continue; + } + + list_for_each_entry_safe(gnt_list_entry, tmp, &rinfo->grants, + node) { + if (gnt_list_entry->gref == GRANT_INVALID_REF || + gnttab_query_foreign_access(gnt_list_entry->gref)) + continue; + + list_del(&gnt_list_entry->node); + gnttab_end_foreign_access(gnt_list_entry->gref, 0, 0UL); + rinfo->persistent_gnts_c--; + __free_page(gnt_list_entry->page); + kfree(gnt_list_entry); + } + + spin_unlock_irqrestore(&rinfo->ring_lock, flags); + } +} + +static void blkfront_delay_work(struct work_struct *work) +{ + struct blkfront_info *info; + bool need_schedule_work = false; + + mutex_lock(&blkfront_mutex); + + list_for_each_entry(info, &info_list, info_list) { + if (info->feature_persistent) { + need_schedule_work = true; + mutex_lock(&info->mutex); + purge_persistent_grants(info); + mutex_unlock(&info->mutex); + } + } + + if (need_schedule_work) + schedule_delayed_work(&blkfront_work, HZ * 10); + + mutex_unlock(&blkfront_mutex); +} + static int __init xlblk_init(void) { int ret; @@ -2655,6 +2737,8 @@ static int __init xlblk_init(void) return -ENODEV; } + INIT_DELAYED_WORK(&blkfront_work, blkfront_delay_work); + ret = xenbus_register_frontend(&blkfront_driver); if (ret) { unregister_blkdev(XENVBD_MAJOR, DEV_NAME); @@ -2668,6 +2752,8 @@ module_init(xlblk_init); static void __exit xlblk_exit(void) { + cancel_delayed_work_sync(&blkfront_work); + xenbus_unregister_driver(&blkfront_driver); unregister_blkdev(XENVBD_MAJOR, DEV_NAME); kfree(minors); From patchwork Mon Aug 13 14:01:12 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?b?SsO8cmdlbiBHcm/Dnw==?= X-Patchwork-Id: 10564275 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9462213B4 for ; Mon, 13 Aug 2018 14:01:53 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 85D8429275 for ; Mon, 13 Aug 2018 14:01:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 79FE029297; Mon, 13 Aug 2018 14:01:53 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7421B29275 for ; Mon, 13 Aug 2018 14:01:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729830AbeHMQnn (ORCPT ); Mon, 13 Aug 2018 12:43:43 -0400 Received: from mx2.suse.de ([195.135.220.15]:60850 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729286AbeHMQnn (ORCPT ); Mon, 13 Aug 2018 12:43:43 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 536D8AFDF; Mon, 13 Aug 2018 14:01:17 +0000 (UTC) From: Juergen Gross To: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, linux-block@vger.kernel.org Cc: konrad.wilk@oracle.com, roger.pau@citrix.com, axboe@kernel.dk, boris.ostrovsky@oracle.com, Juergen Gross Subject: [PATCH v3 3/5] xen/blkfront: reorder tests in xlblk_init() Date: Mon, 13 Aug 2018 16:01:12 +0200 Message-Id: <20180813140114.20126-4-jgross@suse.com> X-Mailer: git-send-email 2.13.7 In-Reply-To: <20180813140114.20126-1-jgross@suse.com> References: <20180813140114.20126-1-jgross@suse.com> MIME-Version: 1.0 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP In case we don't want pv block devices we should not test parameters for sanity and eventually print out error messages. So test precluding conditions before checking parameters. Signed-off-by: Juergen Gross Reviewed-by: Roger Pau Monné --- drivers/block/xen-blkfront.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 7c4b1b9d3971..36e4ca41e765 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -2713,6 +2713,15 @@ static int __init xlblk_init(void) if (!xen_domain()) return -ENODEV; + if (!xen_has_pv_disk_devices()) + return -ENODEV; + + if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) { + pr_warn("xen_blk: can't get major %d with name %s\n", + XENVBD_MAJOR, DEV_NAME); + return -ENODEV; + } + if (xen_blkif_max_segments < BLKIF_MAX_SEGMENTS_PER_REQUEST) xen_blkif_max_segments = BLKIF_MAX_SEGMENTS_PER_REQUEST; @@ -2728,15 +2737,6 @@ static int __init xlblk_init(void) xen_blkif_max_queues = nr_cpus; } - if (!xen_has_pv_disk_devices()) - return -ENODEV; - - if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) { - printk(KERN_WARNING "xen_blk: can't get major %d with name %s\n", - XENVBD_MAJOR, DEV_NAME); - return -ENODEV; - } - INIT_DELAYED_WORK(&blkfront_work, blkfront_delay_work); ret = xenbus_register_frontend(&blkfront_driver); From patchwork Mon Aug 13 14:01:13 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?b?SsO8cmdlbiBHcm/Dnw==?= X-Patchwork-Id: 10564269 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 25EA913B4 for ; Mon, 13 Aug 2018 14:01:45 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 12E1429275 for ; Mon, 13 Aug 2018 14:01:45 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 025E229297; Mon, 13 Aug 2018 14:01:44 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 92C8229275 for ; Mon, 13 Aug 2018 14:01:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729891AbeHMQno (ORCPT ); Mon, 13 Aug 2018 12:43:44 -0400 Received: from mx2.suse.de ([195.135.220.15]:60864 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729638AbeHMQnn (ORCPT ); Mon, 13 Aug 2018 12:43:43 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 8E085B002; Mon, 13 Aug 2018 14:01:17 +0000 (UTC) From: Juergen Gross To: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, linux-block@vger.kernel.org Cc: konrad.wilk@oracle.com, roger.pau@citrix.com, axboe@kernel.dk, boris.ostrovsky@oracle.com, Juergen Gross Subject: [PATCH v3 4/5] xen/blkback: move persistent grants flags to bool Date: Mon, 13 Aug 2018 16:01:13 +0200 Message-Id: <20180813140114.20126-5-jgross@suse.com> X-Mailer: git-send-email 2.13.7 In-Reply-To: <20180813140114.20126-1-jgross@suse.com> References: <20180813140114.20126-1-jgross@suse.com> MIME-Version: 1.0 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The struct persistent_gnt flags member is meant to be a bitfield of different flags. There is only PERSISTENT_GNT_ACTIVE flag left, so convert it to a bool named "active". Signed-off-by: Juergen Gross Reviewed-by: Roger Pau Monné --- drivers/block/xen-blkback/blkback.c | 13 ++++++------- drivers/block/xen-blkback/common.h | 7 +------ 2 files changed, 7 insertions(+), 13 deletions(-) diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index 9eae7b243f68..fd1e19f1a49f 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -255,8 +255,7 @@ static int add_persistent_gnt(struct xen_blkif_ring *ring, } } - bitmap_zero(persistent_gnt->flags, PERSISTENT_GNT_FLAGS_SIZE); - set_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags); + persistent_gnt->active = true; /* Add new node and rebalance tree. */ rb_link_node(&(persistent_gnt->node), parent, new); rb_insert_color(&(persistent_gnt->node), &ring->persistent_gnts); @@ -280,11 +279,11 @@ static struct persistent_gnt *get_persistent_gnt(struct xen_blkif_ring *ring, else if (gref > data->gnt) node = node->rb_right; else { - if(test_bit(PERSISTENT_GNT_ACTIVE, data->flags)) { + if (data->active) { pr_alert_ratelimited("requesting a grant already in use\n"); return NULL; } - set_bit(PERSISTENT_GNT_ACTIVE, data->flags); + data->active = true; atomic_inc(&ring->persistent_gnt_in_use); return data; } @@ -295,10 +294,10 @@ static struct persistent_gnt *get_persistent_gnt(struct xen_blkif_ring *ring, static void put_persistent_gnt(struct xen_blkif_ring *ring, struct persistent_gnt *persistent_gnt) { - if(!test_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags)) + if (!persistent_gnt->active) pr_alert_ratelimited("freeing a grant already unused\n"); persistent_gnt->last_used = jiffies; - clear_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags); + persistent_gnt->active = false; atomic_dec(&ring->persistent_gnt_in_use); } @@ -429,7 +428,7 @@ static void purge_persistent_gnt(struct xen_blkif_ring *ring) BUG_ON(persistent_gnt->handle == BLKBACK_INVALID_HANDLE); - if (test_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags)) + if (persistent_gnt->active) continue; if (!scan_used && !persistent_gnt_timeout(persistent_gnt)) continue; diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h index 7bff72db3b7e..2339b8d39c5e 100644 --- a/drivers/block/xen-blkback/common.h +++ b/drivers/block/xen-blkback/common.h @@ -233,11 +233,6 @@ struct xen_vbd { struct backend_info; -/* Number of available flags */ -#define PERSISTENT_GNT_FLAGS_SIZE 1 -/* This persistent grant is currently in use */ -#define PERSISTENT_GNT_ACTIVE 0 - /* Number of requests that we can fit in a ring */ #define XEN_BLKIF_REQS_PER_PAGE 32 @@ -246,7 +241,7 @@ struct persistent_gnt { grant_ref_t gnt; grant_handle_t handle; unsigned long last_used; - DECLARE_BITMAP(flags, PERSISTENT_GNT_FLAGS_SIZE); + bool active; struct rb_node node; struct list_head remove_node; }; From patchwork Mon Aug 13 14:01:14 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?b?SsO8cmdlbiBHcm/Dnw==?= X-Patchwork-Id: 10564273 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 962431510 for ; Mon, 13 Aug 2018 14:01:48 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8756029275 for ; 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Mon, 13 Aug 2018 14:01:17 +0000 (UTC) From: Juergen Gross To: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, linux-block@vger.kernel.org Cc: konrad.wilk@oracle.com, roger.pau@citrix.com, axboe@kernel.dk, boris.ostrovsky@oracle.com, Juergen Gross Subject: [PATCH v3 5/5] xen/blkback: remove unused pers_gnts_lock from struct xen_blkif_ring Date: Mon, 13 Aug 2018 16:01:14 +0200 Message-Id: <20180813140114.20126-6-jgross@suse.com> X-Mailer: git-send-email 2.13.7 In-Reply-To: <20180813140114.20126-1-jgross@suse.com> References: <20180813140114.20126-1-jgross@suse.com> MIME-Version: 1.0 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP pers_gnts_lock isn't being used anywhere. Remove it. Signed-off-by: Juergen Gross Reviewed-by: Roger Pau Monné --- drivers/block/xen-blkback/common.h | 1 - 1 file changed, 1 deletion(-) diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h index 2339b8d39c5e..1d3002d773f7 100644 --- a/drivers/block/xen-blkback/common.h +++ b/drivers/block/xen-blkback/common.h @@ -269,7 +269,6 @@ struct xen_blkif_ring { wait_queue_head_t pending_free_wq; /* Tree to store persistent grants. */ - spinlock_t pers_gnts_lock; struct rb_root persistent_gnts; unsigned int persistent_gnt_c; atomic_t persistent_gnt_in_use;