diff options
| -rw-r--r-- | kernel/memremap.c | 17 | ||||
| -rw-r--r-- | mm/gup.c | 7 |
2 files changed, 14 insertions, 10 deletions
diff --git a/kernel/memremap.c b/kernel/memremap.c index 3df6cd4ffb40..891c77487a6a 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -507,22 +507,23 @@ struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start) * @pfn: page frame number to lookup page_map * @pgmap: optional known pgmap that already has a reference * - * @pgmap allows the overhead of a lookup to be bypassed when @pfn lands in the - * same mapping. + * If @pgmap is non-NULL and covers @pfn it will be returned as-is. If @pgmap + * is non-NULL but does not cover @pfn the reference to it will be released. */ struct dev_pagemap *get_dev_pagemap(unsigned long pfn, struct dev_pagemap *pgmap) { - const struct resource *res = pgmap ? pgmap->res : NULL; resource_size_t phys = PFN_PHYS(pfn); /* - * In the cached case we're already holding a live reference so - * we can simply do a blind increment + * In the cached case we're already holding a live reference. */ - if (res && phys >= res->start && phys <= res->end) { - percpu_ref_get(pgmap->ref); - return pgmap; + if (pgmap) { + const struct resource *res = pgmap ? pgmap->res : NULL; + + if (res && phys >= res->start && phys <= res->end) + return pgmap; + put_dev_pagemap(pgmap); } /* fall back to slow path lookup */ @@ -1410,7 +1410,6 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, VM_BUG_ON_PAGE(compound_head(page) != head, page); - put_dev_pagemap(pgmap); SetPageReferenced(page); pages[*nr] = page; (*nr)++; @@ -1420,6 +1419,8 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, ret = 1; pte_unmap: + if (pgmap) + put_dev_pagemap(pgmap); pte_unmap(ptem); return ret; } @@ -1459,10 +1460,12 @@ static int __gup_device_huge(unsigned long pfn, unsigned long addr, SetPageReferenced(page); pages[*nr] = page; get_page(page); - put_dev_pagemap(pgmap); (*nr)++; pfn++; } while (addr += PAGE_SIZE, addr != end); + + if (pgmap) + put_dev_pagemap(pgmap); return 1; } |