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 21B603F54D1; Tue, 17 Mar 2026 16:57:51 +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=1773766671; cv=none; b=UHFHTwwMDijbEVwtYTIzaEDpEeT2WcXr2eRzrcodM3mv7Kmh664eDtJPm9Uoi5cZU2eDu0tKLV8VV4fWz7xmf8VMBS20WPED/qapJoC7mtJ01lH7bvTnxuuJm0jLlyzlDcn3zfNmOqGSHbSlJMLaIQZnNqOdyON9YTsAbSxfgWc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773766671; c=relaxed/simple; bh=Bip5aS2Q/tCY3dJyBk4Fs5dKG63YEPL2XgTfzOnLk/o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fKWtgp+KSaWPjxc7QIvjhZ9Ze2a1Jt1XbJDUY+h6DCJf4OxxQeBfsJTi+b8DGRu45JCTSxLLRJVbgHFuotD++m01neKy5Gw+foGUHNyuQleyYuh3Z1A+HK17YAhIM3/ahAhK+Marq0VTXmo2cYrDDPDHUMD9qEBoUXwyH+SfDqU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=qFaMp8J3; 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="qFaMp8J3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7784CC2BCB3; Tue, 17 Mar 2026 16:57:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773766671; bh=Bip5aS2Q/tCY3dJyBk4Fs5dKG63YEPL2XgTfzOnLk/o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qFaMp8J3h6JOzr7rbOeTOYOK/GYkvLK8VsApl75PUwJtmsISNYD4yXcM1jTlZtOyS 6QUsA6N4pt6A0vyltmwEuqpd0PVsjYB8DN+FfJE/RI1AEOUn746O2LL48LlOxm2jHi LkEqSb2ywOlAiDfBzi9Px/MxwS6Lk8ofbJkl0CibC48PbNuFIeBjGnbDBjhxhYFJdL dS7+rCrenGPGw1k1gzHlX9qyAutHDQfjbciY3bY9j8Yt/9XqHc456BsUvXjs7NUvSU 3Kke/jH0KX9ggRX+MNKpMGzCEbVEp/Us+6guRKZrJIs5QIkEXp+3oD39j8g5uPrQHn L96mGSXBg5mBA== From: "David Hildenbrand (Arm)" To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linux-cxl@vger.kernel.org, "David Hildenbrand (Arm)" , Andrew Morton , Oscar Salvador , Axel Rasmussen , Yuanchu Xie , Wei Xu , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko Subject: [PATCH 12/14] mm/sparse: move sparse_init_one_section() to internal.h Date: Tue, 17 Mar 2026 17:56:50 +0100 Message-ID: <20260317165652.99114-13-david@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260317165652.99114-1-david@kernel.org> References: <20260317165652.99114-1-david@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit While at it, convert the BUG_ON to a WARN_ON, avoid long lines, and merge sparse_encode_mem_map() into sparse_init_one_section(). Clarify the comment a bit, pointing at page_to_pfn(). Signed-off-by: David Hildenbrand (Arm) --- include/linux/mmzone.h | 2 +- mm/internal.h | 22 ++++++++++++++++++++++ mm/sparse.c | 24 ------------------------ 3 files changed, 23 insertions(+), 25 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index b694c69dee04..dcbbf36ed88c 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -2008,7 +2008,7 @@ struct mem_section { /* * This is, logically, a pointer to an array of struct * pages. However, it is stored with some other magic. - * (see sparse.c::sparse_init_one_section()) + * (see sparse_init_one_section()) * * Additionally during early boot we encode node id of * the location of the section here to guide allocation. diff --git a/mm/internal.h b/mm/internal.h index 5f5c45d80aca..bcf4df97b185 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -965,6 +965,28 @@ void memmap_init_range(unsigned long, int, unsigned long, unsigned long, */ #ifdef CONFIG_SPARSEMEM void sparse_init(void); + +static inline void sparse_init_one_section(struct mem_section *ms, + unsigned long pnum, struct page *mem_map, + struct mem_section_usage *usage, unsigned long flags) +{ + unsigned long coded_mem_map; + + BUILD_BUG_ON(SECTION_MAP_LAST_BIT > PFN_SECTION_SHIFT); + + /* + * We encode the start PFN of the section into the mem_map such that + * page_to_pfn() on !CONFIG_SPARSEMEM_VMEMMAP can simply subtract it + * from the page pointer to obtain the PFN. + */ + coded_mem_map = (unsigned long)(mem_map - section_nr_to_pfn(pnum)); + VM_WARN_ON(coded_mem_map & ~SECTION_MAP_MASK); + + ms->section_mem_map &= ~SECTION_MAP_MASK; + ms->section_mem_map |= coded_mem_map; + ms->section_mem_map |= SECTION_HAS_MEM_MAP | flags; + ms->usage = usage; +} #else static inline void sparse_init(void) {} #endif /* CONFIG_SPARSEMEM */ diff --git a/mm/sparse.c b/mm/sparse.c index b5a2de43ac40..6f5f340301a3 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -256,30 +256,6 @@ static void __init memblocks_present(void) memory_present(nid, start, end); } -/* - * Subtle, we encode the real pfn into the mem_map such that - * the identity pfn - section_mem_map will return the actual - * physical page frame number. - */ -static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long pnum) -{ - unsigned long coded_mem_map = - (unsigned long)(mem_map - (section_nr_to_pfn(pnum))); - BUILD_BUG_ON(SECTION_MAP_LAST_BIT > PFN_SECTION_SHIFT); - BUG_ON(coded_mem_map & ~SECTION_MAP_MASK); - return coded_mem_map; -} - -static void __meminit sparse_init_one_section(struct mem_section *ms, - unsigned long pnum, struct page *mem_map, - struct mem_section_usage *usage, unsigned long flags) -{ - ms->section_mem_map &= ~SECTION_MAP_MASK; - ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum) - | SECTION_HAS_MEM_MAP | flags; - ms->usage = usage; -} - static unsigned long usemap_size(void) { return BITS_TO_LONGS(SECTION_BLOCKFLAGS_BITS) * sizeof(unsigned long); -- 2.43.0