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 25F6946B2 for ; Mon, 11 Dec 2023 00:55:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="PAWg1yxy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E4F43C433C8; Mon, 11 Dec 2023 00:55:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1702256110; bh=AJ/icjIwEZ0Itq2CqfU83kVD8NYxCySL4M2MgjFmJ5I=; h=Date:To:From:Subject:From; b=PAWg1yxyptZXRqf8tLZmgyLFRezmw/n93GhqY5EgAsShwmBXbUG/H1ycEJRcXTA98 qRep2coM9K7zmxlqHe/boe82uC+q6Qs6RGyqzCSAW32ya+A8Xf7o+UXrh3X6DyV+xz vkAz/qVvCch1pzx08I4I6EQDbcd/RXwRib9Tox2s= Date: Sun, 10 Dec 2023 16:55:09 -0800 To: mm-commits@vger.kernel.org,ira.weiny@intel.com,fabio.maria.de.francesco@linux.intel.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] mm-util-use-kmap_local_page-in-memcmp_pages.patch removed from -mm tree Message-Id: <20231211005509.E4F43C433C8@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm/util: use kmap_local_page() in memcmp_pages() has been removed from the -mm tree. Its filename was mm-util-use-kmap_local_page-in-memcmp_pages.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Fabio De Francesco Subject: mm/util: use kmap_local_page() in memcmp_pages() Date: Mon, 20 Nov 2023 15:15:27 +0100 kmap_atomic() has been deprecated in favor of kmap_local_page(). Therefore, replace kmap_atomic() with kmap_local_page() in memcmp_pages(). 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. In memcmp_pages(), the block of code between the mapping and un-mapping does not depend on the above-mentioned side effects of kmap_aatomic(), so that mere replacements of the old API with the new one is all that is required (i.e., there is no need to explicitly call pagefault_disable() and/or preempt_disable()). Link: https://lkml.kernel.org/r/20231120141554.6612-1-fmdefrancesco@gmail.com Signed-off-by: Fabio M. De Francesco Cc: Ira Weiny Signed-off-by: Andrew Morton --- mm/util.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/mm/util.c~mm-util-use-kmap_local_page-in-memcmp_pages +++ a/mm/util.c @@ -1047,11 +1047,11 @@ int __weak memcmp_pages(struct page *pag char *addr1, *addr2; int ret; - addr1 = kmap_atomic(page1); - addr2 = kmap_atomic(page2); + addr1 = kmap_local_page(page1); + addr2 = kmap_local_page(page2); ret = memcmp(addr1, addr2, PAGE_SIZE); - kunmap_atomic(addr2); - kunmap_atomic(addr1); + kunmap_local(addr2); + kunmap_local(addr1); return ret; } _ Patches currently in -mm which might be from fabio.maria.de.francesco@linux.intel.com are