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 28171262FF6; Mon, 1 Dec 2025 11:33:48 +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=1764588828; cv=none; b=TrC6fbkKhqg8vZGFdnQJbGvTTWI+GDK/ITC6osIBqOAkkeoeSfc7t8WSfAWmll/+zrIB2fN+s9v4RapRPPu4pDYt9P9yTdGrgeMxbEcyjFP7c4md8R3BthBFd8ldZFYQiC/TNCpjNMHh7scRxqSVEXWY2BL7w7PwHb11rro6bJ4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764588828; c=relaxed/simple; bh=DnjhWEskE1xCdHVePKZIxd7PzKM/lNhZsy68PlWIclY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hv9Ox7Id4wYGlUzbxk0CUzqpAdmQUettppwkwr3lz4d1JJcSrQV/0G0CbLAYjIaajyUwrWYd0uCa4nXjG+2x05hFetencM21mKHSdxXxtpnqWd5JZ8o5rgz45j45+ukCip2L2GZKxkUbfoQs3h10QkqapirNBzo1ebGkZIKtKps= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=EN8pXi9b; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="EN8pXi9b" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A1271C113D0; Mon, 1 Dec 2025 11:33:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1764588828; bh=DnjhWEskE1xCdHVePKZIxd7PzKM/lNhZsy68PlWIclY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EN8pXi9bn0muaW13KK8vTnx80Yfv2GFouRRk9dS3UkoQkYWU2JI6p2WWROBvfJJ/O IDSQeTtvPJZxYYfRU5m771jsJ6SR0mhWCbq7Oo2U1Iw0Ic9SAuZ/U/YKWtVb6AJB24 c+FfTt5e+tX3RQdRl3qa6EAwFb1U7oZ/+q2QpDho= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Fabio M. De Francesco" , Ira Weiny , Andrew Morton , Sasha Levin Subject: [PATCH 5.4 184/187] mm/mempool: replace kmap_atomic() with kmap_local_page() Date: Mon, 1 Dec 2025 12:24:52 +0100 Message-ID: <20251201112247.858660384@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20251201112241.242614045@linuxfoundation.org> References: <20251201112241.242614045@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ 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 Signed-off-by: Greg Kroah-Hartman --- 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 */