The patch titled
Subject: add missing page_count() check to vm_insert_pages().
has been added to the -mm tree. Its filename is
mm-add-vm_insert_pages-2.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-add-vm_insert_pages-2.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-add-vm_insert_pages-2.patch
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------------------------------------------------------
From: Arjun Roy <arjunroy@xxxxxxxxxx>
Subject: add missing page_count() check to vm_insert_pages().
Add missing page_count() check to vm_insert_pages(), specifically inside
insert_page_in_batch_locked(). This was accidentally forgotten in the
original patchset.
See: https://marc.info/?l=linux-mm&m=158156166403807&w=2
The intention of this patch-set is to reduce atomic ops for tcp zerocopy
receives, which normally hits the same spinlock multiple times
consecutively.
Link: http://lkml.kernel.org/r/20200214005929.104481-1-arjunroy.kdev@xxxxxxxxx
Signed-off-by: Arjun Roy <arjunroy@xxxxxxxxxx>
Cc: Arjun Roy <arjunroy@xxxxxxxxxx>
Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Soheil Hassas Yeganeh <soheil@xxxxxxxxxx>
Cc: David Miller <davem@xxxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/mm/memory.c~mm-add-vm_insert_pages-2
+++ a/mm/memory.c
@@ -1463,8 +1463,11 @@ static int insert_page_into_pte_locked(s
static int insert_page_in_batch_locked(struct mm_struct *mm, pmd_t *pmd,
unsigned long addr, struct page *page, pgprot_t prot)
{
- const int err = validate_page_before_insert(page);
+ int err;
+ if (!page_count(page))
+ return -EINVAL;
+ err = validate_page_before_insert(page);
return err ? err : insert_page_into_pte_locked(
mm, pte_offset_map(pmd, addr), addr, page, prot);
}
_
Patches currently in -mm which might be from arjunroy@xxxxxxxxxx are
mm-refactor-insert_page-to-prepare-for-batched-lock-insert.patch
mm-add-vm_insert_pages.patch
mm-add-vm_insert_pages-2.patch
net-zerocopy-use-vm_insert_pages-for-tcp-rcv-zerocopy.patch
