On Thu, Apr 11, 2024 at 10:57:24AM +1000, Alistair Popple wrote: > The reference counts for ZONE_DEVICE private pages should be > initialised by the driver when the page is actually allocated by the > driver allocator, not when they are first created. This is currently > the case for MEMORY_DEVICE_PRIVATE and MEMORY_DEVICE_COHERENT pages > but not MEMORY_DEVICE_PCI_P2PDMA pages so fix that up. > > Signed-off-by: Alistair Popple <apopple@xxxxxxxxxx> > --- > drivers/pci/p2pdma.c | 2 ++ > mm/memremap.c | 8 ++++---- > mm/mm_init.c | 4 +++- > 3 files changed, 9 insertions(+), 5 deletions(-) > > diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c > index fa7370f..ab7ef18 100644 > --- a/drivers/pci/p2pdma.c > +++ b/drivers/pci/p2pdma.c > @@ -128,6 +128,8 @@ static int p2pmem_alloc_mmap(struct file *filp, struct kobject *kobj, > goto out; > } > > + get_page(virt_to_page(kaddr)); > + Should this be set_page_count(page, 1) If the refcount is already known to be 0 ? > @@ -508,15 +508,15 @@ void free_zone_device_page(struct page *page) > page->mapping = NULL; > page->pgmap->ops->page_free(page); > > - if (page->pgmap->type != MEMORY_DEVICE_PRIVATE && > - page->pgmap->type != MEMORY_DEVICE_COHERENT) > + if (page->pgmap->type == MEMORY_DEVICE_PRIVATE || > + page->pgmap->type == MEMORY_DEVICE_COHERENT) > + put_dev_pagemap(page->pgmap); Not related, but we should really be getting rid of this devmap refcount traffic too, IMHO.. If an implementation wants this then it should hook the page free/alloc callbacks and do this, not put it in the core code. Jason
