The patch titled
Subject: dax: add empty static inline for CONFIG_DAX=n
has been added to the -mm mm-unstable branch. Its filename is
dax-add-empty-static-inline-for-config_dax=n.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/dax-add-empty-static-inline-for-config_dax=n.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing
your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Mathieu Desnoyers <[email protected]>
Subject: dax: add empty static inline for CONFIG_DAX=n
Date: Thu, 15 Feb 2024 09:46:25 -0500
Patch series "Introduce cpu_dcache_is_aliasing() to fix DAX regression",
v6.
This commit introduced in v4.0 prevents building FS_DAX on 32-bit ARM,
even on ARMv7 which does not have virtually aliased data caches:
commit d92576f1167c ("dax: does not work correctly with virtual aliasing
caches")
Even though it used to work fine before.
The root of the issue here is the fact that DAX was never designed to
handle virtually aliasing data caches (VIVT and VIPT with aliasing data
cache). It touches the pages through their linear mapping, which is not
consistent with the userspace mappings with virtually aliasing data
caches.
This patch series introduces cpu_dcache_is_aliasing() with the new
Kconfig option ARCH_HAS_CPU_CACHE_ALIASING and implements it for all
architectures. The implementation of cpu_dcache_is_aliasing() is either
evaluated to a constant at compile-time or a runtime check, which is
what is needed on ARM.
With this we can basically narrow down the list of architectures which
are unsupported by DAX to those which are really affected.
This patch (of 9):
When building a kernel with CONFIG_DAX=n, all uses of set_dax_nocache()
and set_dax_nomc() need to be either within regions of code or compile
units which are explicitly not compiled, or they need to rely on compiler
optimizations to eliminate calls to those undefined symbols.
It appears that at least the openrisc and loongarch architectures don't
end up eliminating those undefined symbols even if they are provably
within code which is eliminated due to conditional branches depending on
constants.
Implement empty static inline functions for set_dax_nocache() and
set_dax_nomc() in CONFIG_DAX=n to ensure those undefined references are
removed.
Link:
https://lkml.kernel.org/r/[email protected]
Link:
https://lkml.kernel.org/r/[email protected]
Reported-by: kernel test robot <[email protected]>
Closes:
https://lore.kernel.org/oe-kbuild-all/[email protected]/
Reported-by: kernel test robot <[email protected]>
Closes:
https://lore.kernel.org/oe-kbuild-all/[email protected]/
Fixes: 7ac5360cd4d0 ("dax: remove the copy_from_iter and copy_to_iter methods")
Signed-off-by: Mathieu Desnoyers <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Vishal Verma <[email protected]>
Cc: Dave Jiang <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Russell King <[email protected]>
Cc: Dave Chinner <[email protected]>
Cc: Michael Sclafani <[email protected]>
Cc: Alasdair Kergon <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Mike Snitzer <[email protected]>
Cc: Mikulas Patocka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---
include/linux/dax.h | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
--- a/include/linux/dax.h~dax-add-empty-static-inline-for-config_dax=n
+++ a/include/linux/dax.h
@@ -63,6 +63,8 @@ void kill_dax(struct dax_device *dax_dev
void dax_write_cache(struct dax_device *dax_dev, bool wc);
bool dax_write_cache_enabled(struct dax_device *dax_dev);
bool dax_synchronous(struct dax_device *dax_dev);
+void set_dax_nocache(struct dax_device *dax_dev);
+void set_dax_nomc(struct dax_device *dax_dev);
void set_dax_synchronous(struct dax_device *dax_dev);
size_t dax_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff,
void *addr, size_t bytes, struct iov_iter *i);
@@ -109,6 +111,12 @@ static inline bool dax_synchronous(struc
{
return true;
}
+static inline void set_dax_nocache(struct dax_device *dax_dev)
+{
+}
+static inline void set_dax_nomc(struct dax_device *dax_dev)
+{
+}
static inline void set_dax_synchronous(struct dax_device *dax_dev)
{
}
@@ -124,9 +132,6 @@ static inline size_t dax_recovery_write(
}
#endif
-void set_dax_nocache(struct dax_device *dax_dev);
-void set_dax_nomc(struct dax_device *dax_dev);
-
struct writeback_control;
#if defined(CONFIG_BLOCK) && defined(CONFIG_FS_DAX)
int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk);
_
Patches currently in -mm which might be from [email protected] are
nvdimm-pmem-fix-leak-on-dax_add_host-failure.patch
dax-add-empty-static-inline-for-config_dax=n.patch
dax-alloc_dax-return-err_ptr-eopnotsupp-for-config_dax=n.patch
nvdimm-pmem-treat-alloc_dax-eopnotsupp-failure-as-non-fatal.patch
dm-treat-alloc_dax-eopnotsupp-failure-as-non-fatal.patch
dcssblk-handle-alloc_dax-eopnotsupp-failure.patch
virtio-treat-alloc_dax-eopnotsupp-failure-as-non-fatal.patch
dax-check-for-data-cache-aliasing-at-runtime.patch
introduce-cpu_dcache_is_aliasing-across-all-architectures.patch
dax-fix-incorrect-list-of-data-cache-aliasing-architectures.patch
