From: Alistair Popple <apopple@xxxxxxxxxx> Subject: kernel/resource: allow region_intersects users to hold resource_lock Introduce a version of region_intersects() that can be called with the resource_lock already held. This is used in a future fix to __request_free_mem_region(). [akpm@xxxxxxxxxxxxxxxxxxxx: make __region_intersects static] Link: https://lkml.kernel.org/r/20210419070109.4780-1-apopple@xxxxxxxxxx Signed-off-by: Alistair Popple <apopple@xxxxxxxxxx> Cc: David Hildenbrand <david@xxxxxxxxxx> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: John Hubbard <jhubbard@xxxxxxxxxx> Cc: Jerome Glisse <jglisse@xxxxxxxxxx> Cc: Balbir Singh <bsingharora@xxxxxxxxx> Cc: Muchun Song <smuchun@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/resource.c | 52 ++++++++++++++++++++++++++------------------ 1 file changed, 31 insertions(+), 21 deletions(-) --- a/kernel/resource.c~kernel-resource-allow-region_intersects-users-to-hold-resource_lock +++ a/kernel/resource.c @@ -502,6 +502,34 @@ int __weak page_is_ram(unsigned long pfn } EXPORT_SYMBOL_GPL(page_is_ram); +static int __region_intersects(resource_size_t start, size_t size, + unsigned long flags, unsigned long desc) +{ + struct resource res; + int type = 0; int other = 0; + struct resource *p; + + res.start = start; + res.end = start + size - 1; + + for (p = iomem_resource.child; p ; p = p->sibling) { + bool is_type = (((p->flags & flags) == flags) && + ((desc == IORES_DESC_NONE) || + (desc == p->desc))); + + if (resource_overlaps(p, &res)) + is_type ? type++ : other++; + } + + if (type == 0) + return REGION_DISJOINT; + + if (other == 0) + return REGION_INTERSECTS; + + return REGION_MIXED; +} + /** * region_intersects() - determine intersection of region with known resources * @start: region start address @@ -525,31 +553,13 @@ EXPORT_SYMBOL_GPL(page_is_ram); int region_intersects(resource_size_t start, size_t size, unsigned long flags, unsigned long desc) { - struct resource res; - int type = 0; int other = 0; - struct resource *p; - - res.start = start; - res.end = start + size - 1; + int ret; read_lock(&resource_lock); - for (p = iomem_resource.child; p ; p = p->sibling) { - bool is_type = (((p->flags & flags) == flags) && - ((desc == IORES_DESC_NONE) || - (desc == p->desc))); - - if (resource_overlaps(p, &res)) - is_type ? type++ : other++; - } + ret = __region_intersects(start, size, flags, desc); read_unlock(&resource_lock); - if (type == 0) - return REGION_DISJOINT; - - if (other == 0) - return REGION_INTERSECTS; - - return REGION_MIXED; + return ret; } EXPORT_SYMBOL_GPL(region_intersects); _
