kmap_atomic() has been deprecated in favor of kmap_local_page().
Therefore, replace kmap_atomic() with kmap_local_page().
kmap_atomic() is implemented like a kmap_local_page() which also
disables page-faults and preemption (the latter only in !PREEMPT_RT
kernels). The kernel virtual addresses returned by these two API are
only valid in the context of the callers (i.e., they cannot be handed to
other threads).
With kmap_local_page() the mappings are per thread and CPU local like
in kmap_atomic(); however, they can handle page-faults and can be called
from any context (including interrupts). The tasks that call
kmap_local_page() can be preempted and, when they are scheduled to run
again, the kernel virtual addresses are restored and are still valid.
The code blocks between the mappings and un-mappings do not rely on the
above-mentioned side effects of kmap_atomic(), so that mere replacements
of the old API with the new one is all that they require (i.e., there is
no need to explicitly call pagefault_disable() and/or preempt_disable()).
Cc: Ira Weiny <ira.weiny@xxxxxxxxx>
Signed-off-by: Fabio M. De Francesco <fabio.maria.de.francesco@xxxxxxxxxxxxxxx>
---
mm/page_poison.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/mm/page_poison.c b/mm/page_poison.c
index b4f456437b7e..3e9037363cf9 100644
--- a/mm/page_poison.c
+++ b/mm/page_poison.c
@@ -21,13 +21,13 @@ early_param("page_poison", early_page_poison_param);
static void poison_page(struct page *page)
{
- void *addr = kmap_atomic(page);
+ void *addr = kmap_local_page(page);
/* KASAN still think the page is in-use, so skip it. */
kasan_disable_current();
memset(kasan_reset_tag(addr), PAGE_POISON, PAGE_SIZE);
kasan_enable_current();
- kunmap_atomic(addr);
+ kunmap_local(addr);
}
void __kernel_poison_pages(struct page *page, int n)
@@ -77,7 +77,7 @@ static void unpoison_page(struct page *page)
{
void *addr;
- addr = kmap_atomic(page);
+ addr = kmap_local_page(page);
kasan_disable_current();
/*
* Page poisoning when enabled poisons each and every page
@@ -86,7 +86,7 @@ static void unpoison_page(struct page *page)
*/
check_poison_mem(page, kasan_reset_tag(addr), PAGE_SIZE);
kasan_enable_current();
- kunmap_atomic(addr);
+ kunmap_local(addr);
}
void __kernel_unpoison_pages(struct page *page, int n)
--
2.42.0
