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Fri, 14 Feb 2020 23:25:35 +0000 Received: by dev-dsk-anchalag-2a-9c2d1d96.us-west-2.amazon.com (Postfix, from userid 4335130) id D719E4028E; Fri, 14 Feb 2020 23:25:34 +0000 (UTC) Date: Fri, 14 Feb 2020 23:25:34 +0000 From: Anchal Agarwal To: , , , , , , , , , , , , , , , , , , , , , , , , , , , , Message-ID: <890c404c585d7790514527f0c021056a7be6e748.1581721799.git.anchalag@amazon.com> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Precedence: Bulk Subject: [Xen-devel] [RFC PATCH v3 06/12] xen-blkfront: add callbacks for PM suspend and hibernation X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" From: Munehisa Kamata Signed-off-by: Munehisa Kamata --- drivers/block/xen-blkfront.c | 119 ++++++++++++++++++++++++++++++++--- 1 file changed, 112 insertions(+), 7 deletions(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 478120233750..d715ed3cb69a 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -47,6 +47,8 @@ #include #include #include +#include +#include #include #include @@ -79,6 +81,8 @@ enum blkif_state { BLKIF_STATE_DISCONNECTED, BLKIF_STATE_CONNECTED, BLKIF_STATE_SUSPENDED, + BLKIF_STATE_FREEZING, + BLKIF_STATE_FROZEN }; struct grant { @@ -220,6 +224,7 @@ struct blkfront_info struct list_head requests; struct bio_list bio_list; struct list_head info_list; + struct completion wait_backend_disconnected; }; static unsigned int nr_minors; @@ -261,6 +266,7 @@ static DEFINE_SPINLOCK(minor_lock); static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo); static void blkfront_gather_backend_features(struct blkfront_info *info); static int negotiate_mq(struct blkfront_info *info); +static void __blkif_free(struct blkfront_info *info); static int get_id_from_freelist(struct blkfront_ring_info *rinfo) { @@ -995,6 +1001,7 @@ static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size, info->sector_size = sector_size; info->physical_sector_size = physical_sector_size; blkif_set_queue_limits(info); + init_completion(&info->wait_backend_disconnected); return 0; } @@ -1218,6 +1225,8 @@ static void xlvbd_release_gendisk(struct blkfront_info *info) /* Already hold rinfo->ring_lock. */ static inline void kick_pending_request_queues_locked(struct blkfront_ring_info *rinfo) { + if (unlikely(rinfo->dev_info->connected == BLKIF_STATE_FREEZING)) + return; if (!RING_FULL(&rinfo->ring)) blk_mq_start_stopped_hw_queues(rinfo->dev_info->rq, true); } @@ -1341,8 +1350,6 @@ static void blkif_free_ring(struct blkfront_ring_info *rinfo) static void blkif_free(struct blkfront_info *info, int suspend) { - unsigned int i; - /* Prevent new requests being issued until we fix things up. */ info->connected = suspend ? BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED; @@ -1350,6 +1357,13 @@ static void blkif_free(struct blkfront_info *info, int suspend) if (info->rq) blk_mq_stop_hw_queues(info->rq); + __blkif_free(info); +} + +static void __blkif_free(struct blkfront_info *info) +{ + unsigned int i; + for (i = 0; i < info->nr_rings; i++) blkif_free_ring(&info->rinfo[i]); @@ -1553,8 +1567,10 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id) struct blkfront_ring_info *rinfo = (struct blkfront_ring_info *)dev_id; struct blkfront_info *info = rinfo->dev_info; - if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) - return IRQ_HANDLED; + if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) { + if (info->connected != BLKIF_STATE_FREEZING) + return IRQ_HANDLED; + } spin_lock_irqsave(&rinfo->ring_lock, flags); again: @@ -2020,6 +2036,7 @@ static int blkif_recover(struct blkfront_info *info) struct bio *bio; unsigned int segs; + bool frozen = info->connected == BLKIF_STATE_FROZEN; blkfront_gather_backend_features(info); /* Reset limits changed by blk_mq_update_nr_hw_queues(). */ blkif_set_queue_limits(info); @@ -2046,6 +2063,9 @@ static int blkif_recover(struct blkfront_info *info) kick_pending_request_queues(rinfo); } + if (frozen) + return 0; + list_for_each_entry_safe(req, n, &info->requests, queuelist) { /* Requeue pending requests (flush or discard) */ list_del_init(&req->queuelist); @@ -2359,6 +2379,7 @@ static void blkfront_connect(struct blkfront_info *info) return; case BLKIF_STATE_SUSPENDED: + case BLKIF_STATE_FROZEN: /* * If we are recovering from suspension, we need to wait * for the backend to announce it's features before @@ -2476,12 +2497,37 @@ static void blkback_changed(struct xenbus_device *dev, break; case XenbusStateClosed: - if (dev->state == XenbusStateClosed) + if (dev->state == XenbusStateClosed) { + if (info->connected == BLKIF_STATE_FREEZING) { + __blkif_free(info); + info->connected = BLKIF_STATE_FROZEN; + complete(&info->wait_backend_disconnected); + break; + } + break; + } + + /* + * We may somehow receive backend's Closed again while thawing + * or restoring and it causes thawing or restoring to fail. + * Ignore such unexpected state anyway. + */ + if (info->connected == BLKIF_STATE_FROZEN && + dev->state == XenbusStateInitialised) { + dev_dbg(&dev->dev, + "ignore the backend's Closed state: %s", + dev->nodename); + break; + } /* fall through */ case XenbusStateClosing: - if (info) - blkfront_closing(info); + if (info) { + if (info->connected == BLKIF_STATE_FREEZING) + xenbus_frontend_closed(dev); + else + blkfront_closing(info); + } break; } } @@ -2625,6 +2671,62 @@ static void blkif_release(struct gendisk *disk, fmode_t mode) mutex_unlock(&blkfront_mutex); } +static int blkfront_freeze(struct xenbus_device *dev) +{ + unsigned int i; + struct blkfront_info *info = dev_get_drvdata(&dev->dev); + struct blkfront_ring_info *rinfo; + /* This would be reasonable timeout as used in xenbus_dev_shutdown() */ + unsigned int timeout = 5 * HZ; + int err = 0; + + info->connected = BLKIF_STATE_FREEZING; + + blk_mq_freeze_queue(info->rq); + blk_mq_quiesce_queue(info->rq); + + for (i = 0; i < info->nr_rings; i++) { + rinfo = &info->rinfo[i]; + + gnttab_cancel_free_callback(&rinfo->callback); + flush_work(&rinfo->work); + } + + /* Kick the backend to disconnect */ + xenbus_switch_state(dev, XenbusStateClosing); + + /* + * We don't want to move forward before the frontend is diconnected + * from the backend cleanly. + */ + timeout = wait_for_completion_timeout(&info->wait_backend_disconnected, + timeout); + if (!timeout) { + err = -EBUSY; + xenbus_dev_error(dev, err, "Freezing timed out;" + "the device may become inconsistent state"); + } + + return err; +} + +static int blkfront_restore(struct xenbus_device *dev) +{ + struct blkfront_info *info = dev_get_drvdata(&dev->dev); + int err = 0; + + err = talk_to_blkback(dev, info); + blk_mq_unquiesce_queue(info->rq); + blk_mq_unfreeze_queue(info->rq); + + if (err) + goto out; + blk_mq_update_nr_hw_queues(&info->tag_set, info->nr_rings); + +out: + return err; +} + static const struct block_device_operations xlvbd_block_fops = { .owner = THIS_MODULE, @@ -2647,6 +2749,9 @@ static struct xenbus_driver blkfront_driver = { .resume = blkfront_resume, .otherend_changed = blkback_changed, .is_ready = blkfront_is_ready, + .freeze = blkfront_freeze, + .thaw = blkfront_restore, + .restore = blkfront_restore }; static void purge_persistent_grants(struct blkfront_info *info)