5.4-stable review patch. If anyone has any objections, please let me know.
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From: "Fabio M. De Francesco" fabio.maria.de.francesco@linux.intel.com
[ Upstream commit f2bcc99a5e901a13b754648d1dbab60f4adf9375 ]
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 don't 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/20231120142640.7077-1-fabio.maria.de.francesco@lin... 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 Stable-dep-of: ec33b59542d9 ("mm/mempool: fix poisoning order>0 pages with HIGHMEM") Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- mm/mempool.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
--- a/mm/mempool.c +++ b/mm/mempool.c @@ -64,10 +64,10 @@ static void check_element(mempool_t *poo /* Mempools backed by page allocator */ if (pool->free == mempool_free_pages) { int order = (int)(long)pool->pool_data; - void *addr = kmap_atomic((struct page *)element); + void *addr = kmap_local_page((struct page *)element);
__check_element(pool, addr, 1UL << (PAGE_SHIFT + order)); - kunmap_atomic(addr); + kunmap_local(addr); } }
@@ -88,10 +88,10 @@ static void poison_element(mempool_t *po /* Mempools backed by page allocator */ if (pool->alloc == mempool_alloc_pages) { int order = (int)(long)pool->pool_data; - void *addr = kmap_atomic((struct page *)element); + void *addr = kmap_local_page((struct page *)element);
__poison_element(addr, 1UL << (PAGE_SHIFT + order)); - kunmap_atomic(addr); + kunmap_local(addr); } } #else /* CONFIG_DEBUG_SLAB || CONFIG_SLUB_DEBUG_ON */