Merge branch 'pci/p2pdma'

- Release per-CPU pgmap ref when vm_insert_page() fails so we don't hang
  when removing the PCI device (Hou Tao)

- Remove incorrect p2pmem_alloc_mmap() warning about page refcount (Hou
  Tao)

- Reset page reference count when page mapping fails (Alistair Popple)

* pci/p2pdma:
  PCI/P2PDMA: Reset page reference count when page mapping fails
  PCI/P2PDMA: Fix p2pmem_alloc_mmap() warning condition
  PCI/P2PDMA: Release per-CPU pgmap ref when vm_insert_page() fails

1 files changed, 9 insertions, 1 deletions

diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 4a2fc7ab42c3..79a414fd6623 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -147,11 +147,19 @@ static int p2pmem_alloc_mmap(struct file *filp, struct kobject *kobj,
 		 * we have just allocated the page no one else should be
 		 * using it.
 		 */
-		VM_WARN_ON_ONCE_PAGE(!page_ref_count(page), page);
+		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);
+
+			/*
+			 * Reset the page count. We don't use put_page()
+			 * because we don't want to trigger the
+			 * p2pdma_folio_free() path.
+			 */
+			set_page_count(page, 0);
+			percpu_ref_put(ref);
 			return ret;
 		}
 		percpu_ref_get(ref);