Re: [PATCH v4 02/10] xen/blkfront: separate per ring information out of device info

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Mon, Nov 02, 2015 at 12:21:38PM +0800, Bob Liu wrote:
> Split per ring information to an new structure "blkfront_ring_info".
> 
> A ring is the representation of a hardware queue, every vbd device can associate
> with one or more rings depending on how many hardware queues/rings to be used.

This along with the patch built with kbuild looks good.

However you will need to rebase it on top v4.4-rc1 to deal with
"block/xen-blkfront: Make it running on 64KB page granularity"

in mind.
> 
> This patch is a preparation for supporting real multi hardware queues/rings.
> 
> Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
> Signed-off-by: Bob Liu <bob.liu@oracle.com>
> ---
>  drivers/block/xen-blkfront.c | 321 ++++++++++++++++++++++++-------------------
>  1 file changed, 178 insertions(+), 143 deletions(-)
> 
> diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
> index a69c02d..2a557e4 100644
> --- a/drivers/block/xen-blkfront.c
> +++ b/drivers/block/xen-blkfront.c
> @@ -115,6 +115,23 @@ MODULE_PARM_DESC(max_ring_page_order, "Maximum order of pages to be used for the
>  #define RINGREF_NAME_LEN (20)
>  
>  /*
> + *  Per-ring info.
> + *  Every blkfront device can associate with one or more blkfront_ring_info,
> + *  depending on how many hardware queues/rings to be used.
> + */
> +struct blkfront_ring_info {
> +	struct blkif_front_ring ring;
> +	unsigned int ring_ref[XENBUS_MAX_RING_PAGES];
> +	unsigned int evtchn, irq;
> +	struct work_struct work;
> +	struct gnttab_free_callback callback;
> +	struct blk_shadow shadow[BLK_MAX_RING_SIZE];
> +	struct list_head indirect_pages;
> +	unsigned long shadow_free;
> +	struct blkfront_info *dev_info;
> +};
> +
> +/*
>   * We have one of these per vbd, whether ide, scsi or 'other'.  They
>   * hang in private_data off the gendisk structure. We may end up
>   * putting all kinds of interesting stuff here :-)
> @@ -128,18 +145,10 @@ struct blkfront_info
>  	int vdevice;
>  	blkif_vdev_t handle;
>  	enum blkif_state connected;
> -	int ring_ref[XENBUS_MAX_RING_PAGES];
>  	unsigned int nr_ring_pages;
> -	struct blkif_front_ring ring;
> -	unsigned int evtchn, irq;
>  	struct request_queue *rq;
> -	struct work_struct work;
> -	struct gnttab_free_callback callback;
> -	struct blk_shadow shadow[BLK_MAX_RING_SIZE];
>  	struct list_head grants;
> -	struct list_head indirect_pages;
>  	unsigned int persistent_gnts_c;
> -	unsigned long shadow_free;
>  	unsigned int feature_flush;
>  	unsigned int feature_discard:1;
>  	unsigned int feature_secdiscard:1;
> @@ -149,6 +158,7 @@ struct blkfront_info
>  	unsigned int max_indirect_segments;
>  	int is_ready;
>  	struct blk_mq_tag_set tag_set;
> +	struct blkfront_ring_info rinfo;
>  };
>  
>  static unsigned int nr_minors;
> @@ -179,33 +189,35 @@ static DEFINE_SPINLOCK(minor_lock);
>  #define INDIRECT_GREFS(_segs) \
>  	((_segs + SEGS_PER_INDIRECT_FRAME - 1)/SEGS_PER_INDIRECT_FRAME)
>  
> -static int blkfront_setup_indirect(struct blkfront_info *info);
> +static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo);
>  static int blkfront_gather_backend_features(struct blkfront_info *info);
>  
> -static int get_id_from_freelist(struct blkfront_info *info)
> +static int get_id_from_freelist(struct blkfront_ring_info *rinfo)
>  {
> -	unsigned long free = info->shadow_free;
> -	BUG_ON(free >= BLK_RING_SIZE(info));
> -	info->shadow_free = info->shadow[free].req.u.rw.id;
> -	info->shadow[free].req.u.rw.id = 0x0fffffee; /* debug */
> +	unsigned long free = rinfo->shadow_free;
> +
> +	BUG_ON(free >= BLK_RING_SIZE(rinfo->dev_info));
> +	rinfo->shadow_free = rinfo->shadow[free].req.u.rw.id;
> +	rinfo->shadow[free].req.u.rw.id = 0x0fffffee; /* debug */
>  	return free;
>  }
>  
> -static int add_id_to_freelist(struct blkfront_info *info,
> +static int add_id_to_freelist(struct blkfront_ring_info *rinfo,
>  			       unsigned long id)
>  {
> -	if (info->shadow[id].req.u.rw.id != id)
> +	if (rinfo->shadow[id].req.u.rw.id != id)
>  		return -EINVAL;
> -	if (info->shadow[id].request == NULL)
> +	if (rinfo->shadow[id].request == NULL)
>  		return -EINVAL;
> -	info->shadow[id].req.u.rw.id  = info->shadow_free;
> -	info->shadow[id].request = NULL;
> -	info->shadow_free = id;
> +	rinfo->shadow[id].req.u.rw.id  = rinfo->shadow_free;
> +	rinfo->shadow[id].request = NULL;
> +	rinfo->shadow_free = id;
>  	return 0;
>  }
>  
> -static int fill_grant_buffer(struct blkfront_info *info, int num)
> +static int fill_grant_buffer(struct blkfront_ring_info *rinfo, int num)
>  {
> +	struct blkfront_info *info = rinfo->dev_info;
>  	struct page *granted_page;
>  	struct grant *gnt_list_entry, *n;
>  	int i = 0;
> @@ -341,8 +353,8 @@ static void xlbd_release_minors(unsigned int minor, unsigned int nr)
>  
>  static void blkif_restart_queue_callback(void *arg)
>  {
> -	struct blkfront_info *info = (struct blkfront_info *)arg;
> -	schedule_work(&info->work);
> +	struct blkfront_ring_info *rinfo = (struct blkfront_ring_info *)arg;
> +	schedule_work(&rinfo->work);
>  }
>  
>  static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg)
> @@ -400,7 +412,7 @@ static int blkif_ioctl(struct block_device *bdev, fmode_t mode,
>   *
>   * @req: a request struct
>   */
> -static int blkif_queue_request(struct request *req)
> +static int blkif_queue_request(struct request *req, struct blkfront_ring_info *rinfo)
>  {
>  	struct blkfront_info *info = req->rq_disk->private_data;
>  	struct blkif_request *ring_req;
> @@ -438,9 +450,9 @@ static int blkif_queue_request(struct request *req)
>  		    max_grefs - info->persistent_gnts_c,
>  		    &gref_head) < 0) {
>  			gnttab_request_free_callback(
> -				&info->callback,
> +				&rinfo->callback,
>  				blkif_restart_queue_callback,
> -				info,
> +				rinfo,
>  				max_grefs);
>  			return 1;
>  		}
> @@ -448,9 +460,9 @@ static int blkif_queue_request(struct request *req)
>  		new_persistent_gnts = 0;
>  
>  	/* Fill out a communications ring structure. */
> -	ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
> -	id = get_id_from_freelist(info);
> -	info->shadow[id].request = req;
> +	ring_req = RING_GET_REQUEST(&rinfo->ring, rinfo->ring.req_prod_pvt);
> +	id = get_id_from_freelist(rinfo);
> +	rinfo->shadow[id].request = req;
>  
>  	if (unlikely(req->cmd_flags & (REQ_DISCARD | REQ_SECURE))) {
>  		ring_req->operation = BLKIF_OP_DISCARD;
> @@ -466,7 +478,7 @@ static int blkif_queue_request(struct request *req)
>  		       req->nr_phys_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);
>  		BUG_ON(info->max_indirect_segments &&
>  		       req->nr_phys_segments > info->max_indirect_segments);
> -		nseg = blk_rq_map_sg(req->q, req, info->shadow[id].sg);
> +		nseg = blk_rq_map_sg(req->q, req, rinfo->shadow[id].sg);
>  		ring_req->u.rw.id = id;
>  		if (nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST) {
>  			/*
> @@ -509,7 +521,7 @@ static int blkif_queue_request(struct request *req)
>  			}
>  			ring_req->u.rw.nr_segments = nseg;
>  		}
> -		for_each_sg(info->shadow[id].sg, sg, nseg, i) {
> +		for_each_sg(rinfo->shadow[id].sg, sg, nseg, i) {
>  			fsect = sg->offset >> 9;
>  			lsect = fsect + (sg->length >> 9) - 1;
>  
> @@ -525,14 +537,14 @@ static int blkif_queue_request(struct request *req)
>  					struct page *indirect_page;
>  
>  					/* Fetch a pre-allocated page to use for indirect grefs */
> -					BUG_ON(list_empty(&info->indirect_pages));
> -					indirect_page = list_first_entry(&info->indirect_pages,
> +					BUG_ON(list_empty(&rinfo->indirect_pages));
> +					indirect_page = list_first_entry(&rinfo->indirect_pages,
>  					                                 struct page, lru);
>  					list_del(&indirect_page->lru);
>  					pfn = page_to_pfn(indirect_page);
>  				}
>  				gnt_list_entry = get_grant(&gref_head, pfn, info);
> -				info->shadow[id].indirect_grants[n] = gnt_list_entry;
> +				rinfo->shadow[id].indirect_grants[n] = gnt_list_entry;
>  				segments = kmap_atomic(pfn_to_page(gnt_list_entry->pfn));
>  				ring_req->u.indirect.indirect_grefs[n] = gnt_list_entry->gref;
>  			}
> @@ -540,7 +552,7 @@ static int blkif_queue_request(struct request *req)
>  			gnt_list_entry = get_grant(&gref_head, page_to_pfn(sg_page(sg)), info);
>  			ref = gnt_list_entry->gref;
>  
> -			info->shadow[id].grants_used[i] = gnt_list_entry;
> +			rinfo->shadow[id].grants_used[i] = gnt_list_entry;
>  
>  			if (rq_data_dir(req) && info->feature_persistent) {
>  				char *bvec_data;
> @@ -586,10 +598,10 @@ static int blkif_queue_request(struct request *req)
>  			kunmap_atomic(segments);
>  	}
>  
> -	info->ring.req_prod_pvt++;
> +	rinfo->ring.req_prod_pvt++;
>  
>  	/* Keep a private copy so we can reissue requests when recovering. */
> -	info->shadow[id].req = *ring_req;
> +	rinfo->shadow[id].req = *ring_req;
>  
>  	if (new_persistent_gnts)
>  		gnttab_free_grant_references(gref_head);
> @@ -598,14 +610,14 @@ static int blkif_queue_request(struct request *req)
>  }
>  
>  
> -static inline void flush_requests(struct blkfront_info *info)
> +static inline void flush_requests(struct blkfront_ring_info *rinfo)
>  {
>  	int notify;
>  
> -	RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&info->ring, notify);
> +	RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&rinfo->ring, notify);
>  
>  	if (notify)
> -		notify_remote_via_irq(info->irq);
> +		notify_remote_via_irq(rinfo->irq);
>  }
>  
>  static inline bool blkif_request_flush_invalid(struct request *req,
> @@ -621,20 +633,20 @@ static inline bool blkif_request_flush_invalid(struct request *req,
>  static int blkif_queue_rq(struct blk_mq_hw_ctx *hctx,
>  			   const struct blk_mq_queue_data *qd)
>  {
> -	struct blkfront_info *info = qd->rq->rq_disk->private_data;
> +	struct blkfront_ring_info *rinfo = (struct blkfront_ring_info *)hctx->driver_data;
>  
>  	blk_mq_start_request(qd->rq);
>  	spin_lock_irq(&info->io_lock);
> -	if (RING_FULL(&info->ring))
> +	if (RING_FULL(&rinfo->ring))
>  		goto out_busy;
>  
> -	if (blkif_request_flush_invalid(qd->rq, info))
> +	if (blkif_request_flush_invalid(qd->rq, rinfo->dev_info))
>  		goto out_err;
>  
> -	if (blkif_queue_request(qd->rq))
> +	if (blkif_queue_request(qd->rq, rinfo))
>  		goto out_busy;
>  
> -	flush_requests(info);
> +	flush_requests(rinfo);
>  	spin_unlock_irq(&info->io_lock);
>  	return BLK_MQ_RQ_QUEUE_OK;
>  
> @@ -648,9 +660,19 @@ out_busy:
>  	return BLK_MQ_RQ_QUEUE_BUSY;
>  }
>  
> +static int blk_mq_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
> +			    unsigned int index)
> +{
> +	struct blkfront_info *info = (struct blkfront_info *)data;
> +
> +	hctx->driver_data = &info->rinfo;
> +	return 0;
> +}
> +
>  static struct blk_mq_ops blkfront_mq_ops = {
>  	.queue_rq = blkif_queue_rq,
>  	.map_queue = blk_mq_map_queue,
> +	.init_hctx = blk_mq_init_hctx,
>  };
>  
>  static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size,
> @@ -903,6 +925,7 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
>  static void xlvbd_release_gendisk(struct blkfront_info *info)
>  {
>  	unsigned int minor, nr_minors;
> +	struct blkfront_ring_info *rinfo = &info->rinfo;
>  
>  	if (info->rq == NULL)
>  		return;
> @@ -911,10 +934,10 @@ static void xlvbd_release_gendisk(struct blkfront_info *info)
>  	blk_mq_stop_hw_queues(info->rq);
>  
>  	/* No more gnttab callback work. */
> -	gnttab_cancel_free_callback(&info->callback);
> +	gnttab_cancel_free_callback(&rinfo->callback);
>  
>  	/* Flush gnttab callback work. Must be done with no locks held. */
> -	flush_work(&info->work);
> +	flush_work(&rinfo->work);
>  
>  	del_gendisk(info->gd);
>  
> @@ -931,20 +954,20 @@ static void xlvbd_release_gendisk(struct blkfront_info *info)
>  }
>  
>  /* Must be called with io_lock holded */
> -static void kick_pending_request_queues(struct blkfront_info *info)
> +static void kick_pending_request_queues(struct blkfront_ring_info *rinfo)
>  {
> -	if (!RING_FULL(&info->ring))
> -		blk_mq_start_stopped_hw_queues(info->rq, true);
> +	if (!RING_FULL(&rinfo->ring))
> +		blk_mq_start_stopped_hw_queues(rinfo->dev_info->rq, true);
>  }
>  
>  static void blkif_restart_queue(struct work_struct *work)
>  {
> -	struct blkfront_info *info = container_of(work, struct blkfront_info, work);
> +	struct blkfront_ring_info *rinfo = container_of(work, struct blkfront_ring_info, work);
>  
> -	spin_lock_irq(&info->io_lock);
> -	if (info->connected == BLKIF_STATE_CONNECTED)
> -		kick_pending_request_queues(info);
> -	spin_unlock_irq(&info->io_lock);
> +	spin_lock_irq(&rinfo->dev_info->io_lock);
> +	if (rinfo->dev_info->connected == BLKIF_STATE_CONNECTED)
> +		kick_pending_request_queues(rinfo);
> +	spin_unlock_irq(&rinfo->dev_info->io_lock);
>  }
>  
>  static void blkif_free(struct blkfront_info *info, int suspend)
> @@ -952,6 +975,7 @@ static void blkif_free(struct blkfront_info *info, int suspend)
>  	struct grant *persistent_gnt;
>  	struct grant *n;
>  	int i, j, segs;
> +	struct blkfront_ring_info *rinfo = &info->rinfo;
>  
>  	/* Prevent new requests being issued until we fix things up. */
>  	spin_lock_irq(&info->io_lock);
> @@ -964,7 +988,7 @@ static void blkif_free(struct blkfront_info *info, int suspend)
>  	/* Remove all persistent grants */
>  	if (!list_empty(&info->grants)) {
>  		list_for_each_entry_safe(persistent_gnt, n,
> -		                         &info->grants, node) {
> +					 &info->grants, node) {
>  			list_del(&persistent_gnt->node);
>  			if (persistent_gnt->gref != GRANT_INVALID_REF) {
>  				gnttab_end_foreign_access(persistent_gnt->gref,
> @@ -982,11 +1006,11 @@ static void blkif_free(struct blkfront_info *info, int suspend)
>  	 * Remove indirect pages, this only happens when using indirect
>  	 * descriptors but not persistent grants
>  	 */
> -	if (!list_empty(&info->indirect_pages)) {
> +	if (!list_empty(&rinfo->indirect_pages)) {
>  		struct page *indirect_page, *n;
>  
>  		BUG_ON(info->feature_persistent);
> -		list_for_each_entry_safe(indirect_page, n, &info->indirect_pages, lru) {
> +		list_for_each_entry_safe(indirect_page, n, &rinfo->indirect_pages, lru) {
>  			list_del(&indirect_page->lru);
>  			__free_page(indirect_page);
>  		}
> @@ -997,21 +1021,21 @@ static void blkif_free(struct blkfront_info *info, int suspend)
>  		 * Clear persistent grants present in requests already
>  		 * on the shared ring
>  		 */
> -		if (!info->shadow[i].request)
> +		if (!rinfo->shadow[i].request)
>  			goto free_shadow;
>  
> -		segs = info->shadow[i].req.operation == BLKIF_OP_INDIRECT ?
> -		       info->shadow[i].req.u.indirect.nr_segments :
> -		       info->shadow[i].req.u.rw.nr_segments;
> +		segs = rinfo->shadow[i].req.operation == BLKIF_OP_INDIRECT ?
> +		       rinfo->shadow[i].req.u.indirect.nr_segments :
> +		       rinfo->shadow[i].req.u.rw.nr_segments;
>  		for (j = 0; j < segs; j++) {
> -			persistent_gnt = info->shadow[i].grants_used[j];
> +			persistent_gnt = rinfo->shadow[i].grants_used[j];
>  			gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
>  			if (info->feature_persistent)
>  				__free_page(pfn_to_page(persistent_gnt->pfn));
>  			kfree(persistent_gnt);
>  		}
>  
> -		if (info->shadow[i].req.operation != BLKIF_OP_INDIRECT)
> +		if (rinfo->shadow[i].req.operation != BLKIF_OP_INDIRECT)
>  			/*
>  			 * If this is not an indirect operation don't try to
>  			 * free indirect segments
> @@ -1019,45 +1043,45 @@ static void blkif_free(struct blkfront_info *info, int suspend)
>  			goto free_shadow;
>  
>  		for (j = 0; j < INDIRECT_GREFS(segs); j++) {
> -			persistent_gnt = info->shadow[i].indirect_grants[j];
> +			persistent_gnt = rinfo->shadow[i].indirect_grants[j];
>  			gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
>  			__free_page(pfn_to_page(persistent_gnt->pfn));
>  			kfree(persistent_gnt);
>  		}
>  
>  free_shadow:
> -		kfree(info->shadow[i].grants_used);
> -		info->shadow[i].grants_used = NULL;
> -		kfree(info->shadow[i].indirect_grants);
> -		info->shadow[i].indirect_grants = NULL;
> -		kfree(info->shadow[i].sg);
> -		info->shadow[i].sg = NULL;
> +		kfree(rinfo->shadow[i].grants_used);
> +		rinfo->shadow[i].grants_used = NULL;
> +		kfree(rinfo->shadow[i].indirect_grants);
> +		rinfo->shadow[i].indirect_grants = NULL;
> +		kfree(rinfo->shadow[i].sg);
> +		rinfo->shadow[i].sg = NULL;
>  	}
>  
>  	/* No more gnttab callback work. */
> -	gnttab_cancel_free_callback(&info->callback);
> +	gnttab_cancel_free_callback(&rinfo->callback);
>  	spin_unlock_irq(&info->io_lock);
>  
>  	/* Flush gnttab callback work. Must be done with no locks held. */
> -	flush_work(&info->work);
> +	flush_work(&rinfo->work);
>  
>  	/* Free resources associated with old device channel. */
>  	for (i = 0; i < info->nr_ring_pages; i++) {
> -		if (info->ring_ref[i] != GRANT_INVALID_REF) {
> -			gnttab_end_foreign_access(info->ring_ref[i], 0, 0);
> -			info->ring_ref[i] = GRANT_INVALID_REF;
> +		if (rinfo->ring_ref[i] != GRANT_INVALID_REF) {
> +			gnttab_end_foreign_access(rinfo->ring_ref[i], 0, 0);
> +			rinfo->ring_ref[i] = GRANT_INVALID_REF;
>  		}
>  	}
> -	free_pages((unsigned long)info->ring.sring, get_order(info->nr_ring_pages * PAGE_SIZE));
> -	info->ring.sring = NULL;
> +	free_pages((unsigned long)rinfo->ring.sring, get_order(info->nr_ring_pages * PAGE_SIZE));
> +	rinfo->ring.sring = NULL;
>  
> -	if (info->irq)
> -		unbind_from_irqhandler(info->irq, info);
> -	info->evtchn = info->irq = 0;
> +	if (rinfo->irq)
> +		unbind_from_irqhandler(rinfo->irq, rinfo);
> +	rinfo->evtchn = rinfo->irq = 0;
>  
>  }
>  
> -static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info,
> +static void blkif_completion(struct blk_shadow *s, struct blkfront_ring_info *rinfo,
>  			     struct blkif_response *bret)
>  {
>  	int i = 0;
> @@ -1065,6 +1089,7 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info,
>  	char *bvec_data;
>  	void *shared_data;
>  	int nseg;
> +	struct blkfront_info *info = rinfo->dev_info;
>  
>  	nseg = s->req.operation == BLKIF_OP_INDIRECT ?
>  		s->req.u.indirect.nr_segments : s->req.u.rw.nr_segments;
> @@ -1126,7 +1151,7 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info,
>  				 */
>  				if (!info->feature_persistent) {
>  					indirect_page = pfn_to_page(s->indirect_grants[i]->pfn);
> -					list_add(&indirect_page->lru, &info->indirect_pages);
> +					list_add(&indirect_page->lru, &rinfo->indirect_pages);
>  				}
>  				s->indirect_grants[i]->gref = GRANT_INVALID_REF;
>  				list_add_tail(&s->indirect_grants[i]->node, &info->grants);
> @@ -1141,7 +1166,8 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
>  	struct blkif_response *bret;
>  	RING_IDX i, rp;
>  	unsigned long flags;
> -	struct blkfront_info *info = (struct blkfront_info *)dev_id;
> +	struct blkfront_ring_info *rinfo = (struct blkfront_ring_info *)dev_id;
> +	struct blkfront_info *info = rinfo->dev_info;
>  	int error;
>  
>  	spin_lock_irqsave(&info->io_lock, flags);
> @@ -1152,13 +1178,13 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
>  	}
>  
>   again:
> -	rp = info->ring.sring->rsp_prod;
> +	rp = rinfo->ring.sring->rsp_prod;
>  	rmb(); /* Ensure we see queued responses up to 'rp'. */
>  
> -	for (i = info->ring.rsp_cons; i != rp; i++) {
> +	for (i = rinfo->ring.rsp_cons; i != rp; i++) {
>  		unsigned long id;
>  
> -		bret = RING_GET_RESPONSE(&info->ring, i);
> +		bret = RING_GET_RESPONSE(&rinfo->ring, i);
>  		id   = bret->id;
>  		/*
>  		 * The backend has messed up and given us an id that we would
> @@ -1172,12 +1198,12 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
>  			 * the id is busted. */
>  			continue;
>  		}
> -		req  = info->shadow[id].request;
> +		req  = rinfo->shadow[id].request;
>  
>  		if (bret->operation != BLKIF_OP_DISCARD)
> -			blkif_completion(&info->shadow[id], info, bret);
> +			blkif_completion(&rinfo->shadow[id], rinfo, bret);
>  
> -		if (add_id_to_freelist(info, id)) {
> +		if (add_id_to_freelist(rinfo, id)) {
>  			WARN(1, "%s: response to %s (id %ld) couldn't be recycled!\n",
>  			     info->gd->disk_name, op_name(bret->operation), id);
>  			continue;
> @@ -1206,7 +1232,7 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
>  				error = -EOPNOTSUPP;
>  			}
>  			if (unlikely(bret->status == BLKIF_RSP_ERROR &&
> -				     info->shadow[id].req.u.rw.nr_segments == 0)) {
> +				     rinfo->shadow[id].req.u.rw.nr_segments == 0)) {
>  				printk(KERN_WARNING "blkfront: %s: empty %s op failed\n",
>  				       info->gd->disk_name, op_name(bret->operation));
>  				error = -EOPNOTSUPP;
> @@ -1231,17 +1257,17 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
>  		}
>  	}
>  
> -	info->ring.rsp_cons = i;
> +	rinfo->ring.rsp_cons = i;
>  
> -	if (i != info->ring.req_prod_pvt) {
> +	if (i != rinfo->ring.req_prod_pvt) {
>  		int more_to_do;
> -		RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do);
> +		RING_FINAL_CHECK_FOR_RESPONSES(&rinfo->ring, more_to_do);
>  		if (more_to_do)
>  			goto again;
>  	} else
> -		info->ring.sring->rsp_event = i + 1;
> +		rinfo->ring.sring->rsp_event = i + 1;
>  
> -	kick_pending_request_queues(info);
> +	kick_pending_request_queues(rinfo);
>  
>  	spin_unlock_irqrestore(&info->io_lock, flags);
>  
> @@ -1250,15 +1276,16 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
>  
>  
>  static int setup_blkring(struct xenbus_device *dev,
> -			 struct blkfront_info *info)
> +			 struct blkfront_ring_info *rinfo)
>  {
>  	struct blkif_sring *sring;
>  	int err, i;
> +	struct blkfront_info *info = rinfo->dev_info;
>  	unsigned long ring_size = info->nr_ring_pages * PAGE_SIZE;
>  	grant_ref_t gref[XENBUS_MAX_RING_PAGES];
>  
>  	for (i = 0; i < info->nr_ring_pages; i++)
> -		info->ring_ref[i] = GRANT_INVALID_REF;
> +		rinfo->ring_ref[i] = GRANT_INVALID_REF;
>  
>  	sring = (struct blkif_sring *)__get_free_pages(GFP_NOIO | __GFP_HIGH,
>  						       get_order(ring_size));
> @@ -1267,29 +1294,29 @@ static int setup_blkring(struct xenbus_device *dev,
>  		return -ENOMEM;
>  	}
>  	SHARED_RING_INIT(sring);
> -	FRONT_RING_INIT(&info->ring, sring, ring_size);
> +	FRONT_RING_INIT(&rinfo->ring, sring, ring_size);
>  
> -	err = xenbus_grant_ring(dev, info->ring.sring, info->nr_ring_pages, gref);
> +	err = xenbus_grant_ring(dev, rinfo->ring.sring, info->nr_ring_pages, gref);
>  	if (err < 0) {
>  		free_pages((unsigned long)sring, get_order(ring_size));
> -		info->ring.sring = NULL;
> +		rinfo->ring.sring = NULL;
>  		goto fail;
>  	}
>  	for (i = 0; i < info->nr_ring_pages; i++)
> -		info->ring_ref[i] = gref[i];
> +		rinfo->ring_ref[i] = gref[i];
>  
> -	err = xenbus_alloc_evtchn(dev, &info->evtchn);
> +	err = xenbus_alloc_evtchn(dev, &rinfo->evtchn);
>  	if (err)
>  		goto fail;
>  
> -	err = bind_evtchn_to_irqhandler(info->evtchn, blkif_interrupt, 0,
> -					"blkif", info);
> +	err = bind_evtchn_to_irqhandler(rinfo->evtchn, blkif_interrupt, 0,
> +					"blkif", rinfo);
>  	if (err <= 0) {
>  		xenbus_dev_fatal(dev, err,
>  				 "bind_evtchn_to_irqhandler failed");
>  		goto fail;
>  	}
> -	info->irq = err;
> +	rinfo->irq = err;
>  
>  	return 0;
>  fail:
> @@ -1307,6 +1334,7 @@ static int talk_to_blkback(struct xenbus_device *dev,
>  	int err, i;
>  	unsigned int max_page_order = 0;
>  	unsigned int ring_page_order = 0;
> +	struct blkfront_ring_info *rinfo = &info->rinfo;
>  
>  	err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
>  			   "max-ring-page-order", "%u", &max_page_order);
> @@ -1318,7 +1346,7 @@ static int talk_to_blkback(struct xenbus_device *dev,
>  	}
>  
>  	/* Create shared ring, alloc event channel. */
> -	err = setup_blkring(dev, info);
> +	err = setup_blkring(dev, rinfo);
>  	if (err)
>  		goto out;
>  
> @@ -1331,7 +1359,7 @@ again:
>  
>  	if (info->nr_ring_pages == 1) {
>  		err = xenbus_printf(xbt, dev->nodename,
> -				    "ring-ref", "%u", info->ring_ref[0]);
> +				    "ring-ref", "%u", rinfo->ring_ref[0]);
>  		if (err) {
>  			message = "writing ring-ref";
>  			goto abort_transaction;
> @@ -1349,7 +1377,7 @@ again:
>  
>  			snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u", i);
>  			err = xenbus_printf(xbt, dev->nodename, ring_ref_name,
> -					    "%u", info->ring_ref[i]);
> +					    "%u", rinfo->ring_ref[i]);
>  			if (err) {
>  				message = "writing ring-ref";
>  				goto abort_transaction;
> @@ -1357,7 +1385,7 @@ again:
>  		}
>  	}
>  	err = xenbus_printf(xbt, dev->nodename,
> -			    "event-channel", "%u", info->evtchn);
> +			    "event-channel", "%u", rinfo->evtchn);
>  	if (err) {
>  		message = "writing event-channel";
>  		goto abort_transaction;
> @@ -1383,8 +1411,8 @@ again:
>  	}
>  
>  	for (i = 0; i < BLK_RING_SIZE(info); i++)
> -		info->shadow[i].req.u.rw.id = i+1;
> -	info->shadow[BLK_RING_SIZE(info)-1].req.u.rw.id = 0x0fffffff;
> +		rinfo->shadow[i].req.u.rw.id = i+1;
> +	rinfo->shadow[BLK_RING_SIZE(info)-1].req.u.rw.id = 0x0fffffff;
>  	xenbus_switch_state(dev, XenbusStateInitialised);
>  
>  	return 0;
> @@ -1410,6 +1438,7 @@ static int blkfront_probe(struct xenbus_device *dev,
>  {
>  	int err, vdevice;
>  	struct blkfront_info *info;
> +	struct blkfront_ring_info *rinfo;
>  
>  	/* FIXME: Use dynamic device id if this is not set. */
>  	err = xenbus_scanf(XBT_NIL, dev->nodename,
> @@ -1459,15 +1488,18 @@ static int blkfront_probe(struct xenbus_device *dev,
>  		return -ENOMEM;
>  	}
>  
> +	rinfo = &info->rinfo;
> +	INIT_LIST_HEAD(&rinfo->indirect_pages);
> +	rinfo->dev_info = info;
> +	INIT_WORK(&rinfo->work, blkif_restart_queue);
> +
>  	mutex_init(&info->mutex);
>  	spin_lock_init(&info->io_lock);
>  	info->xbdev = dev;
>  	info->vdevice = vdevice;
>  	INIT_LIST_HEAD(&info->grants);
> -	INIT_LIST_HEAD(&info->indirect_pages);
>  	info->persistent_gnts_c = 0;
>  	info->connected = BLKIF_STATE_DISCONNECTED;
> -	INIT_WORK(&info->work, blkif_restart_queue);
>  
>  	/* Front end dir is a number, which is used as the id. */
>  	info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0);
> @@ -1501,19 +1533,20 @@ static int blkif_recover(struct blkfront_info *info)
>  	int pending, size;
>  	struct split_bio *split_bio;
>  	struct list_head requests;
> +	struct blkfront_ring_info *rinfo = &info->rinfo;
>  
>  	/* Stage 1: Make a safe copy of the shadow state. */
> -	copy = kmemdup(info->shadow, sizeof(info->shadow),
> +	copy = kmemdup(rinfo->shadow, sizeof(rinfo->shadow),
>  		       GFP_NOIO | __GFP_REPEAT | __GFP_HIGH);
>  	if (!copy)
>  		return -ENOMEM;
>  
>  	/* Stage 2: Set up free list. */
> -	memset(&info->shadow, 0, sizeof(info->shadow));
> +	memset(&rinfo->shadow, 0, sizeof(rinfo->shadow));
>  	for (i = 0; i < BLK_RING_SIZE(info); i++)
> -		info->shadow[i].req.u.rw.id = i+1;
> -	info->shadow_free = info->ring.req_prod_pvt;
> -	info->shadow[BLK_RING_SIZE(info)-1].req.u.rw.id = 0x0fffffff;
> +		rinfo->shadow[i].req.u.rw.id = i+1;
> +	rinfo->shadow_free = rinfo->ring.req_prod_pvt;
> +	rinfo->shadow[BLK_RING_SIZE(info)-1].req.u.rw.id = 0x0fffffff;
>  
>  	rc = blkfront_gather_backend_features(info);
>  	if (rc) {
> @@ -1559,7 +1592,7 @@ static int blkif_recover(struct blkfront_info *info)
>  	info->connected = BLKIF_STATE_CONNECTED;
>  
>  	/* Kick any other new requests queued since we resumed */
> -	kick_pending_request_queues(info);
> +	kick_pending_request_queues(rinfo);
>  
>  	list_for_each_entry_safe(req, n, &requests, queuelist) {
>  		/* Requeue pending requests (flush or discard) */
> @@ -1693,17 +1726,18 @@ static void blkfront_setup_discard(struct blkfront_info *info)
>  		info->feature_secdiscard = !!discard_secure;
>  }
>  
> -static int blkfront_setup_indirect(struct blkfront_info *info)
> +static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo)
>  {
>  	unsigned int segs;
>  	int err, i;
> +	struct blkfront_info *info = rinfo->dev_info;
>  
>  	if (info->max_indirect_segments == 0)
>  		segs = BLKIF_MAX_SEGMENTS_PER_REQUEST;
>  	else
>  		segs = info->max_indirect_segments;
>  
> -	err = fill_grant_buffer(info, (segs + INDIRECT_GREFS(segs)) * BLK_RING_SIZE(info));
> +	err = fill_grant_buffer(rinfo, (segs + INDIRECT_GREFS(segs)) * BLK_RING_SIZE(info));
>  	if (err)
>  		goto out_of_memory;
>  
> @@ -1715,31 +1749,31 @@ static int blkfront_setup_indirect(struct blkfront_info *info)
>  		 */
>  		int num = INDIRECT_GREFS(segs) * BLK_RING_SIZE(info);
>  
> -		BUG_ON(!list_empty(&info->indirect_pages));
> +		BUG_ON(!list_empty(&rinfo->indirect_pages));
>  		for (i = 0; i < num; i++) {
>  			struct page *indirect_page = alloc_page(GFP_NOIO);
>  			if (!indirect_page)
>  				goto out_of_memory;
> -			list_add(&indirect_page->lru, &info->indirect_pages);
> +			list_add(&indirect_page->lru, &rinfo->indirect_pages);
>  		}
>  	}
>  
>  	for (i = 0; i < BLK_RING_SIZE(info); i++) {
> -		info->shadow[i].grants_used = kzalloc(
> -			sizeof(info->shadow[i].grants_used[0]) * segs,
> +		rinfo->shadow[i].grants_used = kzalloc(
> +			sizeof(rinfo->shadow[i].grants_used[0]) * segs,
>  			GFP_NOIO);
> -		info->shadow[i].sg = kzalloc(sizeof(info->shadow[i].sg[0]) * segs, GFP_NOIO);
> +		rinfo->shadow[i].sg = kzalloc(sizeof(rinfo->shadow[i].sg[0]) * segs, GFP_NOIO);
>  		if (info->max_indirect_segments)
> -			info->shadow[i].indirect_grants = kzalloc(
> -				sizeof(info->shadow[i].indirect_grants[0]) *
> +			rinfo->shadow[i].indirect_grants = kzalloc(
> +				sizeof(rinfo->shadow[i].indirect_grants[0]) *
>  				INDIRECT_GREFS(segs),
>  				GFP_NOIO);
> -		if ((info->shadow[i].grants_used == NULL) ||
> -			(info->shadow[i].sg == NULL) ||
> +		if ((rinfo->shadow[i].grants_used == NULL) ||
> +			(rinfo->shadow[i].sg == NULL) ||
>  		     (info->max_indirect_segments &&
> -		     (info->shadow[i].indirect_grants == NULL)))
> +		     (rinfo->shadow[i].indirect_grants == NULL)))
>  			goto out_of_memory;
> -		sg_init_table(info->shadow[i].sg, segs);
> +		sg_init_table(rinfo->shadow[i].sg, segs);
>  	}
>  
>  
> @@ -1747,16 +1781,16 @@ static int blkfront_setup_indirect(struct blkfront_info *info)
>  
>  out_of_memory:
>  	for (i = 0; i < BLK_RING_SIZE(info); i++) {
> -		kfree(info->shadow[i].grants_used);
> -		info->shadow[i].grants_used = NULL;
> -		kfree(info->shadow[i].sg);
> -		info->shadow[i].sg = NULL;
> -		kfree(info->shadow[i].indirect_grants);
> -		info->shadow[i].indirect_grants = NULL;
> +		kfree(rinfo->shadow[i].grants_used);
> +		rinfo->shadow[i].grants_used = NULL;
> +		kfree(rinfo->shadow[i].sg);
> +		rinfo->shadow[i].sg = NULL;
> +		kfree(rinfo->shadow[i].indirect_grants);
> +		rinfo->shadow[i].indirect_grants = NULL;
>  	}
> -	if (!list_empty(&info->indirect_pages)) {
> +	if (!list_empty(&rinfo->indirect_pages)) {
>  		struct page *indirect_page, *n;
> -		list_for_each_entry_safe(indirect_page, n, &info->indirect_pages, lru) {
> +		list_for_each_entry_safe(indirect_page, n, &rinfo->indirect_pages, lru) {
>  			list_del(&indirect_page->lru);
>  			__free_page(indirect_page);
>  		}
> @@ -1823,7 +1857,7 @@ static int blkfront_gather_backend_features(struct blkfront_info *info)
>  		info->max_indirect_segments = min(indirect_segments,
>  						  xen_blkif_max_segments);
>  
> -	return blkfront_setup_indirect(info);
> +	return blkfront_setup_indirect(&info->rinfo);
>  }
>  
>  /*
> @@ -1837,6 +1871,7 @@ static void blkfront_connect(struct blkfront_info *info)
>  	unsigned int physical_sector_size;
>  	unsigned int binfo;
>  	int err;
> +	struct blkfront_ring_info *rinfo = &info->rinfo;
>  
>  	switch (info->connected) {
>  	case BLKIF_STATE_CONNECTED:
> @@ -1913,7 +1948,7 @@ static void blkfront_connect(struct blkfront_info *info)
>  	/* Kick pending requests. */
>  	spin_lock_irq(&info->io_lock);
>  	info->connected = BLKIF_STATE_CONNECTED;
> -	kick_pending_request_queues(info);
> +	kick_pending_request_queues(rinfo);
>  	spin_unlock_irq(&info->io_lock);
>  
>  	add_disk(info->gd);
> -- 
> 1.8.3.1
>