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authorFabio M. De Francesco <fabio.maria.de.francesco@linux.intel.com>2023-11-20 15:28:23 +0100
committerAndrew Morton <akpm@linux-foundation.org>2023-12-10 16:51:50 -0800
commitf542b8e582abd93df092c4a2763679e380f14645 (patch)
tree2361686c5f92a18d525b9cff94465e74fe98afc0
parentf2bcc99a5e901a13b754648d1dbab60f4adf9375 (diff)
mm/page_poison: replace kmap_atomic() with kmap_local_page()
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()). Link: https://lkml.kernel.org/r/20231120142836.7219-1-fabio.maria.de.francesco@linux.intel.com Signed-off-by: Fabio M. De Francesco <fabio.maria.de.francesco@linux.intel.com> Cc: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--mm/page_poison.c8
1 files 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)