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 3FB75269AEE for ; Mon, 24 Nov 2025 21:33:32 +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=1764020013; cv=none; b=fij1/fFPPJQG0Q1HOgQPU6xttO6U5JiHXOKBiBn46PinxdZtC9iyGewfOtRENUCofix3PEitnaK0uWdvqvnaZ0NM7ZxNKsRZhUPXXTax/Id2rLFhpqjDwpyq3Y/5WdFX2iJpm6IqOTdxf4BniRdqmPKqYxsGCqpZKA9MrKnV+L4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764020013; c=relaxed/simple; bh=HSGXj2K2EfLSSYf1CsYQSH8CdtpzAwNZmkXNH2/C5bw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=JaaRBGqXsYyNko75Qm5wp/mLmXYNtuT+vKofeMGrK1wRPQj+w+vv8CAqOe6vz01vLm+Jk3aIoDnF52ITbmyS8iJvpZIEu/Q5UqsYKrmSAwJJYGI3bzrClWoXnF9dA5zC9Xb/uGQL3tkj3aa3vTNhl9pBeoWdZaHImJqXXf7BuXw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rY2BYiG7; 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="rY2BYiG7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1DFA0C4CEF1; Mon, 24 Nov 2025 21:33:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764020012; bh=HSGXj2K2EfLSSYf1CsYQSH8CdtpzAwNZmkXNH2/C5bw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rY2BYiG7Pf8geFEsn+0wKWtrmeW+jwxwTiRJxAH7ylCkRUlq2H6/ZYc83JZRpEmad +dhv3EwOpyRsxc0GgplN09nFQv4aa03vOCY5bJniYzWiaDbLuYzbpfe3shC6cK3DWx WMMZKsJD678VVIphINmvqUQrwJ0FE2ftuduiJSAvL/PpBC+0OIZ4Qw5OyyHqtddd5n CC+UtpmnqwSZsmZUbpSLmr3uCvaEFGE9QxzzqHqqWlUjZmU9mpv/LQZTf8APsK8Ia8 yHAis1BkNYa6JGrxQzC9Xs+yhYeNgD+qlbc0A6LL1yA5aqySn5pmQ1Akslx96OD3yr xENxyc67iLd4w== From: Sasha Levin To: stable@vger.kernel.org Cc: "Fabio M. De Francesco" , Ira Weiny , Andrew Morton , Sasha Levin Subject: [PATCH 5.15.y 1/2] mm/mempool: replace kmap_atomic() with kmap_local_page() Date: Mon, 24 Nov 2025 16:33:29 -0500 Message-ID: <20251124213330.39729-1-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <2025112436-unabashed-tacky-b8b3@gregkh> References: <2025112436-unabashed-tacky-b8b3@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 0b8afbec3e358..802ca5db52696 100644 --- a/mm/mempool.c +++ b/mm/mempool.c @@ -63,10 +63,10 @@ static void check_element(mempool_t *pool, void *element) } else if (pool->free == mempool_free_pages) { /* Mempools backed by page allocator */ 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); } } @@ -86,10 +86,10 @@ static void poison_element(mempool_t *pool, void *element) } else if (pool->alloc == mempool_alloc_pages) { /* Mempools backed by page allocator */ 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