On 2024-09-09 22:14, 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 | 6 ++++++ > mm/memremap.c | 17 +++++++++++++---- > mm/mm_init.c | 22 ++++++++++++++++++---- > 3 files changed, 37 insertions(+), 8 deletions(-) > > diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c > index 4f47a13..210b9f4 100644 > --- a/drivers/pci/p2pdma.c > +++ b/drivers/pci/p2pdma.c > @@ -129,6 +129,12 @@ static int p2pmem_alloc_mmap(struct file *filp, struct kobject *kobj, > } > > /* > + * Initialise the refcount for the freshly allocated page. As we have > + * just allocated the page no one else should be using it. > + */ > + set_page_count(virt_to_page(kaddr), 1); > + > + /* > * vm_insert_page() can sleep, so a reference is taken to mapping > * such that rcu_read_unlock() can be done before inserting the > * pages This seems to only set reference count to the first page, when there can be more than one page referenced by kaddr. I suspect the page count adjustment should be done in the for loop that's a few lines lower than this. I think a similar mistake was made by other recent changes. Thanks, Logan
