From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 96F9332E6BE for ; Mon, 24 Nov 2025 21:43:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764020616; cv=none; b=uQseujcHZ5wdjvVzHMUAY2I2tF4f4gFFdLFe9fi/v8u+UvFHsUcGNZQFPUWbkfD2l304Yhj9HTC6pbRrIwq8sZPM8VMIPzc6FlKbXK61of5kpf4N9YtqAePZAAJUuLBY/6lkkDc8XBliIG+6Tpcdf1GSh79b6BGSnNnaPj2qS0E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764020616; c=relaxed/simple; bh=TPMLa8SgG3qXNLOxSZG3E4o46uE532DZy+ftd6LFtQc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ClCx4J2v8zC4WnElnUatbzS8NewtFdN8r7GMsEII6wcpkkInfIdms3GO8xWtiL+n03yuk8z4rtqrB6Wprm72v1oPfGM3kqKJHezFSFc5udH+pSFIouBT6xtbVGzpBZmPzddf7xgzCdlvVavvw9hShcL6HDMtzkx9hj2khRmiuNc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fQx2+Okg; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="fQx2+Okg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C6666C4CEF1; Mon, 24 Nov 2025 21:43:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764020616; bh=TPMLa8SgG3qXNLOxSZG3E4o46uE532DZy+ftd6LFtQc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fQx2+OkgYOUFUXrZyVv3lZw+srrRZxl42kMGXAl9hUXyTKLIgAemxGfDyrTQ/fS70 vh+xry7fdsmEF4lfdLOyjkvuamuVjmoWc/JIsWprisqyGgKKZ1P6Qwl4+3px76+6x1 q/WUR4Biov3S1S/ueJu6vYLVAJUDgXLJRR1nlu7JyP6myWlF3lcgeRSTrwhZY+tfak zs9sUfQYjvdXj8Ga7NMlk0WOseqwLHLYlOv06xBVCS+0PA8ZGnVNBUACYYZNQ3uxGG iJYl1N/WgsrwNC6OhbrT+OOpz9mHP7RyAwrkf1FeDgwWwy4KhpIxIep0IxYZSpiXY9 8Jz6b9PQX01gA== From: Sasha Levin To: stable@vger.kernel.org Cc: "Fabio M. De Francesco" , Ira Weiny , Andrew Morton , Sasha Levin Subject: [PATCH 5.4.y 1/2] mm/mempool: replace kmap_atomic() with kmap_local_page() Date: Mon, 24 Nov 2025 16:43:33 -0500 Message-ID: <20251124214334.44494-1-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <2025112438-stoppable-bribe-71e6@gregkh> References: <2025112438-stoppable-bribe-71e6@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: "Fabio M. De Francesco" [ 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@linux.intel.com Signed-off-by: Fabio M. De Francesco Cc: Ira Weiny Signed-off-by: Andrew Morton Stable-dep-of: ec33b59542d9 ("mm/mempool: fix poisoning order>0 pages with HIGHMEM") Signed-off-by: Sasha Levin --- mm/mempool.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/mm/mempool.c b/mm/mempool.c index 85efab3da7204..f9f2afe42b92a 100644 --- a/mm/mempool.c +++ b/mm/mempool.c @@ -64,10 +64,10 @@ static void check_element(mempool_t *pool, void *element) /* 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 *pool, void *element) /* 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 */ -- 2.51.0