Re: [PATCH 4/6] xen/blkback: use grant-table.c hypercall wrappers

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

On Wed, Dec 14, 2011 at 03:12:12PM -0500, Daniel De Graaf wrote:
> Now that the grant table hypercall wrappers support mappings without
> GNTMAP_contains_pte, they should be used instead of invoking the
> hypercalls manually.

Hey Jens,

Same deal with this patch as with the other one I sent. Part of a
patchset, and this particular code moves the mucking around to the
existing library that does the mucking around.

It can be applied seperatly so I can also just move this patch
to my "stable/for-jens.3.3" patch series if that would make it easier
for you?

Thanks!
> 
> Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
> ---
>  drivers/block/xen-blkback/blkback.c |   29 ++++-------------------------
>  1 files changed, 4 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
> index 15ec4db..1e256dc 100644
> --- a/drivers/block/xen-blkback/blkback.c
> +++ b/drivers/block/xen-blkback/blkback.c
> @@ -324,6 +324,7 @@ struct seg_buf {
>  static void xen_blkbk_unmap(struct pending_req *req)
>  {
>  	struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST];
> +	struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST];
>  	unsigned int i, invcount = 0;
>  	grant_handle_t handle;
>  	int ret;
> @@ -335,25 +336,12 @@ static void xen_blkbk_unmap(struct pending_req *req)
>  		gnttab_set_unmap_op(&unmap[invcount], vaddr(req, i),
>  				    GNTMAP_host_map, handle);
>  		pending_handle(req, i) = BLKBACK_INVALID_HANDLE;
> +		pages[invcount] = virt_to_page(vaddr(req, i));
>  		invcount++;
>  	}
>  
> -	ret = HYPERVISOR_grant_table_op(
> -		GNTTABOP_unmap_grant_ref, unmap, invcount);
> +	ret = gnttab_unmap_refs(unmap, pages, invcount, false);
>  	BUG_ON(ret);
> -	/*
> -	 * Note, we use invcount, so nr->pages, so we can't index
> -	 * using vaddr(req, i).
> -	 */
> -	for (i = 0; i < invcount; i++) {
> -		ret = m2p_remove_override(
> -			virt_to_page(unmap[i].host_addr), false);
> -		if (ret) {
> -			pr_alert(DRV_PFX "Failed to remove M2P override for %lx\n",
> -				 (unsigned long)unmap[i].host_addr);
> -			continue;
> -		}
> -	}
>  }
>  
>  static int xen_blkbk_map(struct blkif_request *req,
> @@ -381,7 +369,7 @@ static int xen_blkbk_map(struct blkif_request *req,
>  				  pending_req->blkif->domid);
>  	}
>  
> -	ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map, nseg);
> +	ret = gnttab_map_refs(map, NULL, &blkbk->pending_page(pending_req, 0), nseg);
>  	BUG_ON(ret);
>  
>  	/*
> @@ -401,15 +389,6 @@ static int xen_blkbk_map(struct blkif_request *req,
>  		if (ret)
>  			continue;
>  
> -		ret = m2p_add_override(PFN_DOWN(map[i].dev_bus_addr),
> -			blkbk->pending_page(pending_req, i), NULL);
> -		if (ret) {
> -			pr_alert(DRV_PFX "Failed to install M2P override for %lx (ret: %d)\n",
> -				 (unsigned long)map[i].dev_bus_addr, ret);
> -			/* We could switch over to GNTTABOP_copy */
> -			continue;
> -		}
> -
>  		seg[i].buf  = map[i].dev_bus_addr |
>  			(req->u.rw.seg[i].first_sect << 9);
>  	}
> -- 
> 1.7.7.4