diff options
| -rw-r--r-- | drivers/pci/p2pdma.c | 13 | ||||
| -rw-r--r-- | mm/memremap.c | 17 | ||||
| -rw-r--r-- | mm/mm_init.c | 22 |
3 files changed, 42 insertions, 10 deletions
diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 0cb7e0aaba0e..04773a865819 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -140,13 +140,22 @@ static int p2pmem_alloc_mmap(struct file *filp, struct kobject *kobj, rcu_read_unlock(); for (vaddr = vma->vm_start; vaddr < vma->vm_end; vaddr += PAGE_SIZE) { - ret = vm_insert_page(vma, vaddr, virt_to_page(kaddr)); + struct page *page = virt_to_page(kaddr); + + /* + * Initialise the refcount for the freshly allocated page. As + * we have just allocated the page no one else should be + * using it. + */ + VM_WARN_ON_ONCE_PAGE(!page_ref_count(page), page); + set_page_count(page, 1); + ret = vm_insert_page(vma, vaddr, page); if (ret) { gen_pool_free(p2pdma->pool, (uintptr_t)kaddr, len); return ret; } percpu_ref_get(ref); - put_page(virt_to_page(kaddr)); + put_page(page); kaddr += PAGE_SIZE; len -= PAGE_SIZE; } diff --git a/mm/memremap.c b/mm/memremap.c index 40d4547ce514..07bbe0eed084 100644 --- a/mm/memremap.c +++ b/mm/memremap.c @@ -488,15 +488,24 @@ void free_zone_device_folio(struct folio *folio) folio->mapping = NULL; folio->page.pgmap->ops->page_free(folio_page(folio, 0)); - if (folio->page.pgmap->type != MEMORY_DEVICE_PRIVATE && - folio->page.pgmap->type != MEMORY_DEVICE_COHERENT) + switch (folio->page.pgmap->type) { + case MEMORY_DEVICE_PRIVATE: + case MEMORY_DEVICE_COHERENT: + put_dev_pagemap(folio->page.pgmap); + break; + + case MEMORY_DEVICE_FS_DAX: + case MEMORY_DEVICE_GENERIC: /* * Reset the refcount to 1 to prepare for handing out the page * again. */ folio_set_count(folio, 1); - else - put_dev_pagemap(folio->page.pgmap); + break; + + case MEMORY_DEVICE_PCI_P2PDMA: + break; + } } void zone_device_page_init(struct page *page) diff --git a/mm/mm_init.c b/mm/mm_init.c index b5047c5ef7d6..dbb92fdf36fe 100644 --- a/mm/mm_init.c +++ b/mm/mm_init.c @@ -1026,12 +1026,26 @@ static void __ref __init_zone_device_page(struct page *page, unsigned long pfn, } /* - * ZONE_DEVICE pages are released directly to the driver page allocator - * which will set the page count to 1 when allocating the page. + * ZONE_DEVICE pages other than MEMORY_TYPE_GENERIC and + * MEMORY_TYPE_FS_DAX pages are released directly to the driver page + * allocator which will set the page count to 1 when allocating the + * page. + * + * MEMORY_TYPE_GENERIC and MEMORY_TYPE_FS_DAX pages automatically have + * their refcount reset to one whenever they are freed (ie. after + * their refcount drops to 0). */ - if (pgmap->type == MEMORY_DEVICE_PRIVATE || - pgmap->type == MEMORY_DEVICE_COHERENT) + switch (pgmap->type) { + case MEMORY_DEVICE_PRIVATE: + case MEMORY_DEVICE_COHERENT: + case MEMORY_DEVICE_PCI_P2PDMA: set_page_count(page, 0); + break; + + case MEMORY_DEVICE_FS_DAX: + case MEMORY_DEVICE_GENERIC: + break; + } } /* |