linux-kernel - [PATCH v2 10/14] fs/dax: Remove FS_DAX

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <bbade6a3154d14d958f5f9cf65fd6424897ec9c2.1750075065.git-series.apopple@nvidia.com>
Date: Mon, 16 Jun 2025 21:58:12 +1000
From: Alistair Popple <apopple@...dia.com>
To: akpm@...ux-foundation.org
Cc: linux-mm@...ck.org,
	Alistair Popple <apopple@...dia.com>,
	gerald.schaefer@...ux.ibm.com,
	dan.j.williams@...el.com,
	jgg@...pe.ca,
	willy@...radead.org,
	david@...hat.com,
	linux-kernel@...r.kernel.org,
	nvdimm@...ts.linux.dev,
	linux-fsdevel@...r.kernel.org,
	linux-ext4@...r.kernel.org,
	linux-xfs@...r.kernel.org,
	jhubbard@...dia.com,
	hch@....de,
	zhang.lyra@...il.com,
	debug@...osinc.com,
	bjorn@...nel.org,
	balbirs@...dia.com,
	lorenzo.stoakes@...cle.com,
	linux-arm-kernel@...ts.infradead.org,
	loongarch@...ts.linux.dev,
	linuxppc-dev@...ts.ozlabs.org,
	linux-riscv@...ts.infradead.org,
	linux-cxl@...r.kernel.org,
	dri-devel@...ts.freedesktop.org,
	John@...ves.net,
	m.szyprowski@...sung.com
Subject: [PATCH v2 10/14] fs/dax: Remove FS_DAX_LIMITED config option

The dcssblk driver was the last user of FS_DAX_LIMITED. That was marked
broken by 653d7825c149 ("dcssblk: mark DAX broken, remove FS_DAX_LIMITED
support") to allow removal of PFN_SPECIAL. However the FS_DAX_LIMITED
config option itself was not removed, so do that now.

Signed-off-by: Alistair Popple <apopple@...dia.com>

---

Changes since v1:

 - New for v2.
---
 fs/Kconfig    |  9 +--------
 fs/dax.c      | 12 ------------
 mm/memremap.c |  4 ----
 3 files changed, 1 insertion(+), 24 deletions(-)

diff --git a/fs/Kconfig b/fs/Kconfig
index 44b6cdd..ccdf371 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -59,7 +59,7 @@ endif # BLOCK
 config FS_DAX
 	bool "File system based Direct Access (DAX) support"
 	depends on MMU
-	depends on ZONE_DEVICE || FS_DAX_LIMITED
+	depends on ZONE_DEVICE
 	select FS_IOMAP
 	select DAX
 	help
@@ -95,13 +95,6 @@ config FS_DAX_PMD
 	depends on ZONE_DEVICE
 	depends on TRANSPARENT_HUGEPAGE
 
-# Selected by DAX drivers that do not expect filesystem DAX to support
-# get_user_pages() of DAX mappings. I.e. "limited" indicates no support
-# for fork() of processes with MAP_SHARED mappings or support for
-# direct-I/O to a DAX mapping.
-config FS_DAX_LIMITED
-	bool
-
 # Posix ACL utility routines
 #
 # Note: Posix ACLs can be implemented without these helpers.  Never use
diff --git a/fs/dax.c b/fs/dax.c
index 7d4ecb9..f4ffb69 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -449,9 +449,6 @@ static void dax_associate_entry(void *entry, struct address_space *mapping,
 	if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry))
 		return;
 
-	if (IS_ENABLED(CONFIG_FS_DAX_LIMITED))
-		return;
-
 	index = linear_page_index(vma, address & ~(size - 1));
 	if (shared && (folio->mapping || dax_folio_is_shared(folio))) {
 		if (folio->mapping)
@@ -474,9 +471,6 @@ static void dax_disassociate_entry(void *entry, struct address_space *mapping,
 {
 	struct folio *folio = dax_to_folio(entry);
 
-	if (IS_ENABLED(CONFIG_FS_DAX_LIMITED))
-		return;
-
 	if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry))
 		return;
 
@@ -768,12 +762,6 @@ struct page *dax_layout_busy_page_range(struct address_space *mapping,
 	pgoff_t end_idx;
 	XA_STATE(xas, &mapping->i_pages, start_idx);
 
-	/*
-	 * In the 'limited' case get_user_pages() for dax is disabled.
-	 */
-	if (IS_ENABLED(CONFIG_FS_DAX_LIMITED))
-		return NULL;
-
 	if (!dax_mapping(mapping))
 		return NULL;
 
diff --git a/mm/memremap.c b/mm/memremap.c
index c417c84..c17e0a6 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -332,10 +332,6 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid)
 		}
 		break;
 	case MEMORY_DEVICE_FS_DAX:
-		if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) {
-			WARN(1, "File system DAX not supported\n");
-			return ERR_PTR(-EINVAL);
-		}
 		params.pgprot = pgprot_decrypted(params.pgprot);
 		break;
 	case MEMORY_DEVICE_GENERIC:
-- 
git-series 0.9.1