From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E6932C79F82 for ; Tue, 8 Sep 2026 11:24:47 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 09B456B0095; Tue, 8 Sep 2026 07:24:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 04CB26B0098; Tue, 8 Sep 2026 07:24:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E82716B0095; Tue, 8 Sep 2026 07:24:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id C21FF6B0095 for ; Tue, 8 Sep 2026 07:24:46 -0400 (EDT) Received: from smtpin29.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 53F4B1A054E for ; Tue, 8 Sep 2026 11:24:46 +0000 (UTC) X-FDA: 85190362572.29.D52A98F Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf02.hostedemail.com (Postfix) with ESMTP id 7CCA080005 for ; Tue, 8 Sep 2026 11:24:44 +0000 (UTC) Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b="Kt/T3D8X"; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf02.hostedemail.com: domain of ljs@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=ljs@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1788866684; b=rqXFga7t/l+rPVVoVYQQTXFjrTpjIcoINC1sAH4SZaZGUl/Fy6XHChyylevuVDFu7IBfcX U5F1TomX04IVRfuBkJ/4nyuC90pf7a0bWwtk5lLNF2fjMqExG1PQu9wCf4cbaUpdReJAli PxwXXe83DkgH/HHQXuEZRVKqG5Cqxg0= ARC-Authentication-Results: i=1; imf02.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b="Kt/T3D8X"; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf02.hostedemail.com: domain of ljs@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=ljs@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1788866684; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=SN9pBsYau6XqA12Xdl8N5Dmjue89SDbE0U+vn84I9OA=; b=aqCycWF1uI6e8H0G+BrAglGd6aIcDPTVmiZE9CBY5q2HVp4U1NmF2Sz0gYrKa6P7w1pfpp jyZjvS0lnbGXpiYNIutHmBMzwb6GjLaCvhkib37yxKOgwnwvgy2hWJOyJ/Tkv30sK19XV1 NfM2rB1fIWAnXMqFraOT5HA3169Y4uw= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id CD82B43D22; Tue, 8 Sep 2026 11:24:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 485D01F00A3D; Tue, 8 Sep 2026 11:24:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788866683; bh=SN9pBsYau6XqA12Xdl8N5Dmjue89SDbE0U+vn84I9OA=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=Kt/T3D8XZpEzIO2N4iiHbSPlr4ezP2rFGrKhB8FxNGJUjNIAUpTwD9HB2w4fSdRXB 3d+G27lYP0VS4+TljcJccGORudcFm1kPDdz4/OEvCSMQ06hhm/tILmG6tXjv+fSxQy zMCIcl9up+LoaF/s+i3mqtqISioFKy9/BCXkdOX0OrxdQ5lfZVcnYbTsAy7l10FKw/ DsKUhaVgrSL3QWN6+1haOn5hhpXGYybvQCKtSVfLx1qeHkhsUox0Tr1QG2JXGHkIYg UC6y/zN+LsXyYlH9dSgiyaqdJXFBbTQor3lMoBMTACgjNNtY5Gk5lqMhdnzWFhkCEo 7x8z0YQX9TC/Q== From: "Lorenzo Stoakes (ARM)" Date: Tue, 08 Sep 2026 12:23:38 +0100 Subject: [PATCH v2 1/6] mm: move drivers/char/mem.c to mm/char-mem.c MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260908-map-private-dev-zero-v2-1-acc7b5625305@kernel.org> References: <20260908-map-private-dev-zero-v2-0-acc7b5625305@kernel.org> In-Reply-To: <20260908-map-private-dev-zero-v2-0-acc7b5625305@kernel.org> To: Arnd Bergmann , Greg Kroah-Hartman , Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Jann Horn , Pedro Falcato , David Hildenbrand , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Hugh Dickins , Baolin Wang , "Matthew Wilcox (Oracle)" , Jan Kara Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org, "Lorenzo Stoakes (ARM)" X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=3650; i=ljs@kernel.org; h=from:subject:message-id; bh=QmSOJwju5TfiPg8slA7VLmMjfjzHO2fnrvsHpTcasuQ=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLLmfyjcdzyWeZOE6yTvbwKf+P1jDhiwHK17HsCu8FHw7 pSpHKH/OkpZGMS4GGTFFFmefxHfHyQSNq/zgr8bzBxWJpAhDFycAjCR+cGMDA1rKx8/uvU/ObR5 C9+U0lkqDLvK95be62aedsT4ueG2cysYGXrNlfuezn9pcvO5e9qxW+tsvDTsSzwdDZrzPZyFtWf fZwMA X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 7CCA080005 X-Stat-Signature: amkwgrwobtjebcw3jjedqj4zciebct7p X-HE-Tag: 1788866684-992783 X-HE-Meta: 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 Qv7TCIlu M5kFxiZsdAsBI/R592roqUg6uo910NOwWQC1Bm3yyRSHLcRMry2UC8U6FMcrj5DSPg6pE1IHDvVar2bQTCf4AgxHjzZAOBSecHRpgPltAV1vS2exFpipiuvr+ZZeLQ8PXzUxkMONXtGiyhhLtRuuFX2EFaZrh9ptRzM/v9ORZ8fw0c+zmlhTuq6KjbR6OfBN30/KwFylu+hhPQ2MUYGYgYu/RmG1U7yGHteuW2Oiy+RZwEgfW8oiQAvJLsuXGC/at3mnXtVcXrT03D4jWKDaZ7sJzXSTVl49MP9npbO/wps9gyzAHQlZMU+4ca8IO3foj63jhUOJKyXeW3EhUw6UCuaZenXdGGMTiyz2tBd+4j0A8Xug= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: The memory character driver implements several mm-specific features and is always compiled into the kernel, so move it to mm/ where it belongs. Among other things the driver implements /dev/mem which provides raw access to physical memory, and /dev/zero which either allows mapping of a shmem region (if mapped with MAP_SHARED) or, uniquely, anonymous memory (if mapped MAP_PRIVATE). This change lays the foundations to allow MAP_PRIVATE-/dev/zero to be mapped precisely the same as anonymous memory is mapped as currently it is an edge case within mm. Also update a couple of comments that reference 'drivers/char/mem.c' to reference 'mm/char-mem.c'. Acked-by: David Hildenbrand (Arm) Acked-by: Mike Rapoport (Microsoft) Signed-off-by: Lorenzo Stoakes (ARM) --- MAINTAINERS | 4 ++-- drivers/char/Makefile | 2 +- mm/Makefile | 3 ++- drivers/char/mem.c => mm/char-mem.c | 2 +- mm/shmem.c | 2 +- 5 files changed, 7 insertions(+), 6 deletions(-) diff --git a/MAINTAINERS b/MAINTAINERS index 2133aec4a200..ebadf4cef076 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17272,7 +17272,7 @@ F: Documentation/ABI/testing/sysfs-kernel-mm-memory-tiers F: Documentation/ABI/testing/sysfs-kernel-mm-numa F: Documentation/admin-guide/mm/ F: Documentation/mm/ -F: drivers/char/mem.c +F: mm/char-mem.c F: include/linux/cma.h F: include/linux/dmapool.h F: include/linux/ioremap.h @@ -17477,7 +17477,7 @@ L: linux-mm@kvack.org S: Maintained W: http://www.linux-mm.org T: git git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm -F: drivers/char/mem.c +F: mm/char-mem.c F: include/trace/events/mmap.h F: fs/proc/task_mmu.c F: fs/proc/task_nommu.c diff --git a/drivers/char/Makefile b/drivers/char/Makefile index a46d7bf7c4c8..bb3bf66937b3 100644 --- a/drivers/char/Makefile +++ b/drivers/char/Makefile @@ -3,7 +3,7 @@ # Makefile for the kernel character device drivers. # -obj-y += mem.o random.o +obj-y += random.o obj-$(CONFIG_TTY_PRINTK) += ttyprintk.o obj-y += misc.o obj-$(CONFIG_TEST_MISC_MINOR) += misc_minor_kunit.o diff --git a/mm/Makefile b/mm/Makefile index e7245cb88c66..2a3ec53d62ee 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -55,7 +55,8 @@ obj-y := filemap.o mempool.o oom_kill.o fadvise.o \ mm_init.o percpu.o slab_common.o \ compaction.o show_mem.o \ interval_tree.o list_lru.o workingset.o \ - debug.o gup.o mmap_lock.o vma_init.o $(mmu-y) + debug.o gup.o mmap_lock.o vma_init.o char-mem.o \ + $(mmu-y) # Give 'page_alloc' its own module-parameter namespace page-alloc-y := page_alloc.o diff --git a/drivers/char/mem.c b/mm/char-mem.c similarity index 99% rename from drivers/char/mem.c rename to mm/char-mem.c index 63253d1de5d7..d2e575545044 100644 --- a/drivers/char/mem.c +++ b/mm/char-mem.c @@ -1,6 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 /* - * linux/drivers/char/mem.c + * mm/char-mem.c * * Copyright (C) 1991, 1992 Linus Torvalds * diff --git a/mm/shmem.c b/mm/shmem.c index 255d69ebceba..c92ed17dbc4a 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2981,7 +2981,7 @@ unsigned long shmem_get_unmapped_area(struct file *file, sb = file_inode(file)->i_sb; } else { /* - * Called directly from mm/mmap.c, or drivers/char/mem.c + * Called directly from mm/mmap.c, or mm/char-mem.c * for "/dev/zero", to create a shared anonymous object. */ if (IS_ERR(shm_mnt)) -- 2.55.0