On 2/29/20 2:49 AM, Claudio Imbrenda wrote:
...
@@ -458,7 +457,6 @@ static struct page *follow_page_pte(struct
vm_area_struct *vma, }
if (flags & FOLL_SPLIT && PageTransCompound(page)) {
- int ret;
get_page(page);
pte_unmap_unlock(ptep, ptl);
lock_page(page);
@@ -475,6 +473,14 @@ static struct page *follow_page_pte(struct
vm_area_struct *vma, page = ERR_PTR(-ENOMEM);
goto out;
}
+ if (flags & FOLL_PIN) {
What about FOLL_GET? Unless your calling code has some sort of
BUG_ON(flags & FOLL_GET), I'm not sure it's a good idea to leave that
case unhandled.
if I understood the semantics of FOLL_PIN correctly, then we don't need
to make the page accessible for FOLL_GET. FOLL_PIN indicates intent to
access the content of the page, whereas FOLL_GET is only for the struct
page.
if we are not touching the content of the page, there is no need to
make it accessible
OK, I hope I'm not overlooking anything, but that sounds correct to me.
thanks,
--
John Hubbard
NVIDIA
