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 9F823C98318 for ; Sat, 26 Sep 2026 10:41:30 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8F4716B008A; Sat, 26 Sep 2026 06:41:29 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8A5646B008C; Sat, 26 Sep 2026 06:41:29 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7E22D6B0092; Sat, 26 Sep 2026 06:41:29 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 5527F6B008A for ; Sat, 26 Sep 2026 06:41:29 -0400 (EDT) Received: from smtpin15.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay06.hostedemail.com (Postfix) with ESMTP id D91ADA6F77 for ; Sat, 26 Sep 2026 10:41:28 +0000 (UTC) X-FDA: 85255571856.15.92DBFB8 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf11.hostedemail.com (Postfix) with ESMTP id 328674000A for ; Sat, 26 Sep 2026 10:41:27 +0000 (UTC) Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=SDlwayMn; spf=pass (imf11.hostedemail.com: domain of ljs@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=ljs@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1790419287; 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=yYKJkgsyGcqD8NIcZETgQbHYP836m/2LLLDtDuu3S7KEWS0WljJLkU89QC22OAahnqgOfn XVtKO7zwIw1w+ETIrE7YB0b7tKMWGd55pSPbwU5LjsiGm144N3nBo69Whku+KV0FhVypS8 jbHpdNXPXxVtNiiiFyPnk6MPhLwiIpQ= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=SDlwayMn; spf=pass (imf11.hostedemail.com: domain of ljs@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=ljs@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1790419287; b=BijogA0gDT1ySp6lwJnPCCRIOcjAYPxTayiTKGvzVwPv+Cr1P+VQIPbP9bAWt2lck0Er8b t6JPIROIhYGt6qJfBm0fy/xSS7sRmXmKCemW+JTv8j4weUZjEklma4wQ88i3u+RiuIMrFA hWEifPSViHYGNjLCz8ydU4HVJxLXShg= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id C4B0A6022E; Sat, 26 Sep 2026 10:41:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 21B241F00893; Sat, 26 Sep 2026 10:41:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790419286; bh=SN9pBsYau6XqA12Xdl8N5Dmjue89SDbE0U+vn84I9OA=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=SDlwayMniSSzMZ/yLnVoRDTY/aOgPvhOA2LDiF/HlKzgD59VRgg8qfLbmWV7AjCq6 KcV2jNVcf1F7ESdYqqNdVr2WdSLVNuqYjM8FKZInbRK6pksEv45OLMbpbPiXYiakAv GzJS+FJWIy3W4WFfo5Ti/kaKJ2vJzLZfe42+vQTxNR8h3N6RwzclBbPRVCG/jNPeY6 sUw2rWFuNimrCLiB4hqW0C2nrzcAH9Wh9uh0Mm4I72cvVZR4P9bdx4pR+3TofHvUSS BAxuw0Jqca/FbYdDyfMaLQlNrMTYCBgzl/QDCcLbquBLipWly0Y6peVXaC44g1vd2b tvEK9r4ONorwA== From: "Lorenzo Stoakes (ARM)" Date: Sat, 26 Sep 2026 11:41:06 +0100 Subject: [PATCH v3 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: <20260926-map-private-dev-zero-v3-1-d4781e84ccfc@kernel.org> References: <20260926-map-private-dev-zero-v3-0-d4781e84ccfc@kernel.org> In-Reply-To: <20260926-map-private-dev-zero-v3-0-d4781e84ccfc@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=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLK2L/Q+/VRBOIGh33GV2KqlxwrmbZjPvVD3V/jBJdNPb NX1ezGptaOUhUGMi0FWTJHl+Rfx/UEiYfM6L/i7wcxhZQIZwsDFKQATyVvAyHB/cdWRts5T9u3f F3OtFtnikhAgN4NTJtCSR8XV/EieSxAjQ9fhBx3mZfcf5SWt3Wt56MQ79hk1mUazDwhltj74mey 5nBkA X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 328674000A X-Stat-Signature: hepoqkdi1zpndbusxqsduk8fdjpm5j11 X-HE-Tag: 1790419287-255215 X-HE-Meta: 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 zEyDVCa4 Ria/rYsoSzcakpBDcOetlU/QvMP6SmEhWNYseJz6KnqYHUMViQUeBHpVUm1Q8l7U516BRa3SwrJC3PHoOKpngVqWKcBdY5jax3OKl43uHPj6UE+05Tt7cM7xqIZrnRS/k6YJragurJLcPoCc7mXEK07hcr0BYvNNhDjBvAhzfYvXc4FEMqVz611CpbSfhQD4A7v8IyqhcGKpQ+ciTDs0DHu/RclPg7Nq2Ea0zaul/6wCbdNrQniy3FJkOUEYB9SJdWKwMBnmQ6r4Sms3EPGI7qUfPGsYwN10Efor6XQ6NQfImpVXiSP+lqimkD7uxdud3kWImPZJmjgN8RCCY7rwHe5Qs+hzkUo4KfO9cxe+Pn2dsY7E= 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