From patchwork Tue Apr 4 14:08:33 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sergei Shtepa X-Patchwork-Id: 13201867 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 1BA97C77B71 for ; Wed, 5 Apr 2023 14:45:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238629AbjDEOpV (ORCPT ); Wed, 5 Apr 2023 10:45:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57838 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238360AbjDEOpS (ORCPT ); Wed, 5 Apr 2023 10:45:18 -0400 Received: from mx2.veeam.com (mx2.veeam.com [64.129.123.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4DFDE61BE; Wed, 5 Apr 2023 07:45:07 -0700 (PDT) Received: from mail.veeam.com (prgmbx01.amust.local [172.24.128.102]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx2.veeam.com (Postfix) with ESMTPS id 2DC5F400FB; Tue, 4 Apr 2023 10:09:17 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=veeam.com; s=mx2-2022; t=1680617357; bh=e6rw8YBWw3j/gV7Bi56cqpNmQ0KMkF30q4/RWwO8V+Q=; h=From:To:CC:Subject:Date:In-Reply-To:References:From; b=j/k+SYPsRtVW0nUdjvjUOeZHctpFUBQFpXMqTbXAcwWPcp6xqFP71zUV3WhJW6p0H ilORauqrHx0EM8q8x+9cKCVIjUsWXy08I57hlpVWNrjar2+7+xHFCTflrMR/wJ2y1Y J2G3kdlWceGJwEFyyNs46SyMP+bPtAE7W9TBbLF/X/FtqpeY26oAGcBKpFTU6ndcvO 1zIY/qX72EgZWSHiSVg/Iy+v9fkEv9UOLna1RkWJflU8mq8za3W330rtHJObYl87/c aCvyWNknZrshzVa4iFLi+Ze1/3BJxLcyre1HjjzyMSCqnFPlZwEVJIcymU4rSYCfsF QDhSwvZO9wivQ== Received: from ssh-deb10-ssd-vb.amust.local (172.24.10.107) by prgmbx01.amust.local (172.24.128.102) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.26; Tue, 4 Apr 2023 16:09:12 +0200 From: Sergei Shtepa To: , , , CC: , , , , , , , , , , , , Subject: [PATCH v3 09/11] blksnap: event queue from the difference storage Date: Tue, 4 Apr 2023 16:08:33 +0200 Message-ID: <20230404140835.25166-10-sergei.shtepa@veeam.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20230404140835.25166-1-sergei.shtepa@veeam.com> References: <20230404140835.25166-1-sergei.shtepa@veeam.com> MIME-Version: 1.0 X-Originating-IP: [172.24.10.107] X-ClientProxiedBy: prgmbx02.amust.local (172.24.128.103) To prgmbx01.amust.local (172.24.128.102) X-EsetResult: clean, is OK X-EsetId: 37303A2924031554657367 X-Veeam-MMEX: True Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Provides transmission of events from the difference storage to the user process. Only two events are currently defined. The first is that there are few free regions in the difference storage. The second is that the request for a free region for storing differences failed with an error, since there are no more free regions left in the difference storage (the snapshot overflow state). Co-developed-by: Christoph Hellwig Signed-off-by: Christoph Hellwig Signed-off-by: Sergei Shtepa --- drivers/block/blksnap/event_queue.c | 87 +++++++++++++++++++++++++++++ drivers/block/blksnap/event_queue.h | 64 +++++++++++++++++++++ 2 files changed, 151 insertions(+) create mode 100644 drivers/block/blksnap/event_queue.c create mode 100644 drivers/block/blksnap/event_queue.h diff --git a/drivers/block/blksnap/event_queue.c b/drivers/block/blksnap/event_queue.c new file mode 100644 index 000000000000..71b7dca97c8d --- /dev/null +++ b/drivers/block/blksnap/event_queue.c @@ -0,0 +1,87 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (C) 2023 Veeam Software Group GmbH */ +#define pr_fmt(fmt) KBUILD_MODNAME "-event_queue: " fmt + +#include +#include +#include "event_queue.h" + +void event_queue_init(struct event_queue *event_queue) +{ + INIT_LIST_HEAD(&event_queue->list); + spin_lock_init(&event_queue->lock); + init_waitqueue_head(&event_queue->wq_head); +} + +void event_queue_done(struct event_queue *event_queue) +{ + struct event *event; + + spin_lock(&event_queue->lock); + while (!list_empty(&event_queue->list)) { + event = list_first_entry(&event_queue->list, struct event, + link); + list_del(&event->link); + event_free(event); + } + spin_unlock(&event_queue->lock); +} + +int event_gen(struct event_queue *event_queue, gfp_t flags, int code, + const void *data, int data_size) +{ + struct event *event; + + event = kzalloc(sizeof(struct event) + data_size, flags); + if (!event) + return -ENOMEM; + + event->time = ktime_get(); + event->code = code; + event->data_size = data_size; + memcpy(event->data, data, data_size); + + pr_debug("Generate event: time=%lld code=%d data_size=%d\n", + event->time, event->code, event->data_size); + + spin_lock(&event_queue->lock); + list_add_tail(&event->link, &event_queue->list); + spin_unlock(&event_queue->lock); + + wake_up(&event_queue->wq_head); + return 0; +} + +struct event *event_wait(struct event_queue *event_queue, + unsigned long timeout_ms) +{ + int ret; + + ret = wait_event_interruptible_timeout(event_queue->wq_head, + !list_empty(&event_queue->list), timeout_ms); + if (ret >= 0) { + struct event *event = ERR_PTR(-ENOENT); + + spin_lock(&event_queue->lock); + if (!list_empty(&event_queue->list)) { + event = list_first_entry(&event_queue->list, + struct event, link); + list_del(&event->link); + } + spin_unlock(&event_queue->lock); + + if (IS_ERR(event)) + pr_debug("Queue list is empty, timeout_ms=%lu\n", timeout_ms); + else + pr_debug("Event received: time=%lld code=%d\n", + event->time, event->code); + return event; + } + if (ret == -ERESTARTSYS) { + pr_debug("event waiting interrupted\n"); + return ERR_PTR(-EINTR); + } + + pr_err("Failed to wait event. errno=%d\n", abs(ret)); + return ERR_PTR(ret); +} diff --git a/drivers/block/blksnap/event_queue.h b/drivers/block/blksnap/event_queue.h new file mode 100644 index 000000000000..252a265df722 --- /dev/null +++ b/drivers/block/blksnap/event_queue.h @@ -0,0 +1,64 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (C) 2023 Veeam Software Group GmbH */ +#ifndef __BLKSNAP_EVENT_QUEUE_H +#define __BLKSNAP_EVENT_QUEUE_H + +#include +#include +#include +#include +#include + +/** + * struct event - An event to be passed to the user space. + * @link: + * The list header allows to combine events from the queue. + * @time: + * A timestamp indicates when an event occurred. + * @code: + * Event code. + * @data_size: + * The number of bytes in the event data array. + * @data: + * An array of event data. + * + * Events can be different, so they contain different data. The size of the + * data array is not defined exactly, but it has limitations. The size of + * the event structure may exceed the PAGE_SIZE. + */ +struct event { + struct list_head link; + ktime_t time; + int code; + int data_size; + char data[1]; /* up to PAGE_SIZE - sizeof(struct blksnap_snapshot_event) */ +}; + +/** + * struct event_queue - A queue of &struct event. + * @list: + * Linked list for storing events. + * @lock: + * Spinlock allows to guarantee safety of the linked list. + * @wq_head: + * A wait queue allows to put a user thread in a waiting state until + * an event appears in the linked list. + */ +struct event_queue { + struct list_head list; + spinlock_t lock; + struct wait_queue_head wq_head; +}; + +void event_queue_init(struct event_queue *event_queue); +void event_queue_done(struct event_queue *event_queue); + +int event_gen(struct event_queue *event_queue, gfp_t flags, int code, + const void *data, int data_size); +struct event *event_wait(struct event_queue *event_queue, + unsigned long timeout_ms); +static inline void event_free(struct event *event) +{ + kfree(event); +}; +#endif /* __BLKSNAP_EVENT_QUEUE_H */