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Commit 69b91ede authored by Bob Liu's avatar Bob Liu Committed by Konrad Rzeszutek Wilk
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drivers: xen-blkback: delay pending_req allocation to connect_ring 



This is a pre-patch for multi-page ring feature.
In connect_ring, we can know exactly how many pages are used for the shared
ring, delay pending_req allocation here so that we won't waste too much memory.

Signed-off-by: default avatarBob Liu <bob.liu@oracle.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent a5768aa8

drivers/block/xen-blkback/common.h

+1 −1
Original line number Diff line number Diff line
@@ -248,7 +248,7 @@ struct backend_info; 
#define PERSISTENT_GNT_WAS_ACTIVE	1



/* Number of requests that we can fit in a ring */

#define XEN_BLKIF_REQS			32

#define XEN_BLKIF_REQS_PER_PAGE		32



struct persistent_gnt {

	struct page *page;

drivers/block/xen-blkback/xenbus.c

+38 −44
Original line number Diff line number Diff line
@@ -124,8 +124,6 @@ static void xen_update_blkif_status(struct xen_blkif *blkif) 
static struct xen_blkif *xen_blkif_alloc(domid_t domid)

{

	struct xen_blkif *blkif;

	struct pending_req *req, *n;

	int i, j;



	BUILD_BUG_ON(MAX_INDIRECT_PAGES > BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST);
@@ -151,51 +149,11 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid) 


	INIT_LIST_HEAD(&blkif->pending_free);

	INIT_WORK(&blkif->free_work, xen_blkif_deferred_free);



	for (i = 0; i < XEN_BLKIF_REQS; i++) {

		req = kzalloc(sizeof(*req), GFP_KERNEL);

		if (!req)

			goto fail;

		list_add_tail(&req->free_list,

		              &blkif->pending_free);

		for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) {

			req->segments[j] = kzalloc(sizeof(*req->segments[0]),

			                           GFP_KERNEL);

			if (!req->segments[j])

				goto fail;

		}

		for (j = 0; j < MAX_INDIRECT_PAGES; j++) {

			req->indirect_pages[j] = kzalloc(sizeof(*req->indirect_pages[0]),

			                                 GFP_KERNEL);

			if (!req->indirect_pages[j])

				goto fail;

		}

	}

	spin_lock_init(&blkif->pending_free_lock);

	init_waitqueue_head(&blkif->pending_free_wq);

	init_waitqueue_head(&blkif->shutdown_wq);



	return blkif;



fail:

	list_for_each_entry_safe(req, n, &blkif->pending_free, free_list) {

		list_del(&req->free_list);

		for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) {

			if (!req->segments[j])

				break;

			kfree(req->segments[j]);

		}

		for (j = 0; j < MAX_INDIRECT_PAGES; j++) {

			if (!req->indirect_pages[j])

				break;

			kfree(req->indirect_pages[j]);

		}

		kfree(req);

	}



	kmem_cache_free(xen_blkif_cachep, blkif);



	return ERR_PTR(-ENOMEM);

}



static int xen_blkif_map(struct xen_blkif *blkif, grant_ref_t gref,
@@ -312,7 +270,7 @@ static void xen_blkif_free(struct xen_blkif *blkif) 
		i++;

	}



	WARN_ON(i != XEN_BLKIF_REQS);

	WARN_ON(i != XEN_BLKIF_REQS_PER_PAGE);



	kmem_cache_free(xen_blkif_cachep, blkif);

}
@@ -864,7 +822,8 @@ static int connect_ring(struct backend_info *be) 
	unsigned int evtchn;

	unsigned int pers_grants;

	char protocol[64] = "";

	int err;

	struct pending_req *req, *n;

	int err, i, j;



	pr_debug("%s %s\n", __func__, dev->otherend);
@@ -905,6 +864,24 @@ static int connect_ring(struct backend_info *be) 
		ring_ref, evtchn, be->blkif->blk_protocol, protocol,

		pers_grants ? "persistent grants" : "");



	for (i = 0; i < XEN_BLKIF_REQS_PER_PAGE; i++) {

		req = kzalloc(sizeof(*req), GFP_KERNEL);

		if (!req)

			goto fail;

		list_add_tail(&req->free_list, &be->blkif->pending_free);

		for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) {

			req->segments[j] = kzalloc(sizeof(*req->segments[0]), GFP_KERNEL);

			if (!req->segments[j])

				goto fail;

		}

		for (j = 0; j < MAX_INDIRECT_PAGES; j++) {

			req->indirect_pages[j] = kzalloc(sizeof(*req->indirect_pages[0]),

							 GFP_KERNEL);

			if (!req->indirect_pages[j])

				goto fail;

		}

	}



	/* Map the shared frame, irq etc. */

	err = xen_blkif_map(be->blkif, ring_ref, evtchn);

	if (err) {
@@ -914,6 +891,23 @@ static int connect_ring(struct backend_info *be) 
	}



	return 0;



fail:

	list_for_each_entry_safe(req, n, &be->blkif->pending_free, free_list) {

		list_del(&req->free_list);

		for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) {

			if (!req->segments[j])

				break;

			kfree(req->segments[j]);

		}

		for (j = 0; j < MAX_INDIRECT_PAGES; j++) {

			if (!req->indirect_pages[j])

				break;

			kfree(req->indirect_pages[j]);

		}

		kfree(req);

	}

	return -ENOMEM;

}



static const struct xenbus_device_id xen_blkbk_ids[] = {