block/xen-blkfront: Store a page rather a pfn in the grant structure

All the usage of the field pfn are done using the same idiom:

pfn_to_page(grant->pfn)

This will  return always the same page. Store directly the page in the
grant to clean up the code.

Signed-off-by: Julien Grall <julien.grall@citrix.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index bf9ccfe03f45830aed13ff98431d19db1e232b3b..7552ca8f8ffe567829351ee11a91498fcdc0f570 100644 (file)
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -68,7 +68,7 @@ enum blkif_state {
 
 struct grant {
        grant_ref_t gref;
-       unsigned long pfn;
+       struct page *page;
        struct list_head node;
 };
 
@@ -221,7 +221,7 @@ static int fill_grant_buffer(struct blkfront_info *info, int num)
                                kfree(gnt_list_entry);
                                goto out_of_memory;
                        }
-                       gnt_list_entry->pfn = page_to_pfn(granted_page);
+                       gnt_list_entry->page = granted_page;
                }
 
                gnt_list_entry->gref = GRANT_INVALID_REF;
@@ -236,7 +236,7 @@ out_of_memory:
                                 &info->grants, node) {
                list_del(&gnt_list_entry->node);
                if (info->feature_persistent)
-                       __free_page(pfn_to_page(gnt_list_entry->pfn));
+                       __free_page(gnt_list_entry->page);
                kfree(gnt_list_entry);
                i--;
        }
@@ -245,8 +245,8 @@ out_of_memory:
 }
 
 static struct grant *get_grant(grant_ref_t *gref_head,
-                               unsigned long pfn,
-                               struct blkfront_info *info)
+                              struct page *page,
+                              struct blkfront_info *info)
 {
        struct grant *gnt_list_entry;
        unsigned long buffer_gfn;
@@ -265,10 +265,10 @@ static struct grant *get_grant(grant_ref_t *gref_head,
        gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head);
        BUG_ON(gnt_list_entry->gref == -ENOSPC);
        if (!info->feature_persistent) {
-               BUG_ON(!pfn);
-               gnt_list_entry->pfn = pfn;
+               BUG_ON(!page);
+               gnt_list_entry->page = page;
        }
-       buffer_gfn = pfn_to_gfn(gnt_list_entry->pfn);
+       buffer_gfn = xen_page_to_gfn(gnt_list_entry->page);
        gnttab_grant_foreign_access_ref(gnt_list_entry->gref,
                                        info->xbdev->otherend_id,
                                        buffer_gfn, 0);
@@ -524,7 +524,7 @@ static int blkif_queue_rw_req(struct request *req)
 
                if ((ring_req->operation == BLKIF_OP_INDIRECT) &&
                    (i % SEGS_PER_INDIRECT_FRAME == 0)) {
-                       unsigned long uninitialized_var(pfn);
+                       struct page *uninitialized_var(page);
 
                        if (segments)
                                kunmap_atomic(segments);
@@ -541,15 +541,15 @@ static int blkif_queue_rw_req(struct request *req)
                                indirect_page = list_first_entry(&info->indirect_pages,
                                                                 struct page, lru);
                                list_del(&indirect_page->lru);
-                               pfn = page_to_pfn(indirect_page);
+                               page = indirect_page;
                        }
-                       gnt_list_entry = get_grant(&gref_head, pfn, info);
+                       gnt_list_entry = get_grant(&gref_head, page, info);
                        info->shadow[id].indirect_grants[n] = gnt_list_entry;
-                       segments = kmap_atomic(pfn_to_page(gnt_list_entry->pfn));
+                       segments = kmap_atomic(gnt_list_entry->page);
                        ring_req->u.indirect.indirect_grefs[n] = gnt_list_entry->gref;
                }
 
-               gnt_list_entry = get_grant(&gref_head, page_to_pfn(sg_page(sg)), info);
+               gnt_list_entry = get_grant(&gref_head, sg_page(sg), info);
                ref = gnt_list_entry->gref;
 
                info->shadow[id].grants_used[i] = gnt_list_entry;
@@ -560,7 +560,7 @@ static int blkif_queue_rw_req(struct request *req)
 
                        BUG_ON(sg->offset + sg->length > PAGE_SIZE);
 
-                       shared_data = kmap_atomic(pfn_to_page(gnt_list_entry->pfn));
+                       shared_data = kmap_atomic(gnt_list_entry->page);
                        bvec_data = kmap_atomic(sg_page(sg));
 
                        /*
@@ -1001,7 +1001,7 @@ static void blkif_free(struct blkfront_info *info, int suspend)
                                info->persistent_gnts_c--;
                        }
                        if (info->feature_persistent)
-                               __free_page(pfn_to_page(persistent_gnt->pfn));
+                               __free_page(persistent_gnt->page);
                        kfree(persistent_gnt);
                }
        }
@@ -1036,7 +1036,7 @@ static void blkif_free(struct blkfront_info *info, int suspend)
                        persistent_gnt = info->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));
+                               __free_page(persistent_gnt->page);
                        kfree(persistent_gnt);
                }
 
@@ -1050,7 +1050,7 @@ static void blkif_free(struct blkfront_info *info, int suspend)
                for (j = 0; j < INDIRECT_GREFS(segs); j++) {
                        persistent_gnt = info->shadow[i].indirect_grants[j];
                        gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
-                       __free_page(pfn_to_page(persistent_gnt->pfn));
+                       __free_page(persistent_gnt->page);
                        kfree(persistent_gnt);
                }
 
@@ -1101,8 +1101,7 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info,
        if (bret->operation == BLKIF_OP_READ && info->feature_persistent) {
                for_each_sg(s->sg, sg, nseg, i) {
                        BUG_ON(sg->offset + sg->length > PAGE_SIZE);
-                       shared_data = kmap_atomic(
-                               pfn_to_page(s->grants_used[i]->pfn));
+                       shared_data = kmap_atomic(s->grants_used[i]->page);
                        bvec_data = kmap_atomic(sg_page(sg));
                        memcpy(bvec_data   + sg->offset,
                               shared_data + sg->offset,
@@ -1154,7 +1153,7 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info,
                                 * available pages for indirect grefs.
                                 */
                                if (!info->feature_persistent) {
-                                       indirect_page = pfn_to_page(s->indirect_grants[i]->pfn);
+                                       indirect_page = s->indirect_grants[i]->page;
                                        list_add(&indirect_page->lru, &info->indirect_pages);
                                }
                                s->indirect_grants[i]->gref = GRANT_INVALID_REF;