+ mm-slab-decouple-arch_kmalloc_minalign-from-arch_dma_minalign.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/slab: decouple ARCH_KMALLOC_MINALIGN from ARCH_DMA_MINALIGN
has been added to the -mm mm-unstable branch.  Its filename is
     mm-slab-decouple-arch_kmalloc_minalign-from-arch_dma_minalign.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-slab-decouple-arch_kmalloc_minalign-from-arch_dma_minalign.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Catalin Marinas <catalin.marinas@arm.com>
Subject: mm/slab: decouple ARCH_KMALLOC_MINALIGN from ARCH_DMA_MINALIGN
Date: Mon, 12 Jun 2023 16:31:45 +0100

Patch series "mm, dma, arm64: Reduce ARCH_KMALLOC_MINALIGN to 8", v7.

A series reducing the kmalloc() minimum alignment on arm64 to 8 (from
128).  


This patch (of 17):

In preparation for supporting a kmalloc() minimum alignment smaller than
the arch DMA alignment, decouple the two definitions.  This requires that
either the kmalloc() caches are aligned to a (run-time) cache-line size or
the DMA API bounces unaligned kmalloc() allocations.  Subsequent patches
will implement both options.

After this patch, ARCH_DMA_MINALIGN is expected to be used in static
alignment annotations and defined by an architecture to be the maximum
alignment for all supported configurations/SoCs in a single Image. 
Architectures opting in to a smaller ARCH_KMALLOC_MINALIGN will need to
define its value in the arch headers.

Since ARCH_DMA_MINALIGN is now always defined, adjust the #ifdef in
dma_get_cache_alignment() so that there is no change for architectures not
requiring a minimum DMA alignment.

Link: https://lkml.kernel.org/r/20230612153201.554742-1-catalin.marinas@arm.com
Link: https://lkml.kernel.org/r/20230612153201.554742-2-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Isaac J. Manjarres <isaacmanjarres@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Will Deacon <will@kernel.org>
Cc: Jerry Snitselaar <jsnitsel@redhat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/cache.h       |    6 ++++++
 include/linux/dma-mapping.h |    3 ++-
 include/linux/slab.h        |   14 ++++++++++----
 3 files changed, 18 insertions(+), 5 deletions(-)

--- a/include/linux/cache.h~mm-slab-decouple-arch_kmalloc_minalign-from-arch_dma_minalign
+++ a/include/linux/cache.h
@@ -98,4 +98,10 @@ struct cacheline_padding {
 #define CACHELINE_PADDING(name)
 #endif
 
+#ifdef ARCH_DMA_MINALIGN
+#define ARCH_HAS_DMA_MINALIGN
+#else
+#define ARCH_DMA_MINALIGN __alignof__(unsigned long long)
+#endif
+
 #endif /* __LINUX_CACHE_H */
--- a/include/linux/dma-mapping.h~mm-slab-decouple-arch_kmalloc_minalign-from-arch_dma_minalign
+++ a/include/linux/dma-mapping.h
@@ -2,6 +2,7 @@
 #ifndef _LINUX_DMA_MAPPING_H
 #define _LINUX_DMA_MAPPING_H
 
+#include <linux/cache.h>
 #include <linux/sizes.h>
 #include <linux/string.h>
 #include <linux/device.h>
@@ -545,7 +546,7 @@ static inline int dma_set_min_align_mask
 
 static inline int dma_get_cache_alignment(void)
 {
-#ifdef ARCH_DMA_MINALIGN
+#ifdef ARCH_HAS_DMA_MINALIGN
 	return ARCH_DMA_MINALIGN;
 #endif
 	return 1;
--- a/include/linux/slab.h~mm-slab-decouple-arch_kmalloc_minalign-from-arch_dma_minalign
+++ a/include/linux/slab.h
@@ -12,6 +12,7 @@
 #ifndef _LINUX_SLAB_H
 #define	_LINUX_SLAB_H
 
+#include <linux/cache.h>
 #include <linux/gfp.h>
 #include <linux/overflow.h>
 #include <linux/types.h>
@@ -235,12 +236,17 @@ void kmem_dump_obj(void *object);
  * alignment larger than the alignment of a 64-bit integer.
  * Setting ARCH_DMA_MINALIGN in arch headers allows that.
  */
-#if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
+#ifdef ARCH_HAS_DMA_MINALIGN
+#if ARCH_DMA_MINALIGN > 8 && !defined(ARCH_KMALLOC_MINALIGN)
 #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
-#define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
-#define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN)
-#else
+#endif
+#endif
+
+#ifndef ARCH_KMALLOC_MINALIGN
 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
+#elif ARCH_KMALLOC_MINALIGN > 8
+#define KMALLOC_MIN_SIZE ARCH_KMALLOC_MINALIGN
+#define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
 #endif
 
 /*
_

Patches currently in -mm which might be from catalin.marinas@arm.com are

mm-slab-decouple-arch_kmalloc_minalign-from-arch_dma_minalign.patch
dma-allow-dma_get_cache_alignment-to-be-overridden-by-the-arch-code.patch
mm-slab-simplify-create_kmalloc_cache-args-and-make-it-static.patch
mm-slab-limit-kmalloc-minimum-alignment-to-dma_get_cache_alignment.patch
drivers-base-use-arch_dma_minalign-instead-of-arch_kmalloc_minalign.patch
drivers-gpu-use-arch_dma_minalign-instead-of-arch_kmalloc_minalign.patch
drivers-usb-use-arch_dma_minalign-instead-of-arch_kmalloc_minalign.patch
drivers-spi-use-arch_dma_minalign-instead-of-arch_kmalloc_minalign.patch
dm-crypt-use-arch_dma_minalign-instead-of-arch_kmalloc_minalign.patch
iio-core-use-arch_dma_minalign-instead-of-arch_kmalloc_minalign.patch
arm64-allow-kmalloc-caches-aligned-to-the-smaller-cache_line_size.patch
dma-mapping-force-bouncing-if-the-kmalloc-size-is-not-cache-line-aligned.patch
iommu-dma-force-bouncing-if-the-size-is-not-cacheline-aligned.patch
mm-slab-reduce-the-kmalloc-minimum-alignment-if-dma-bouncing-possible.patch
arm64-enable-arch_want_kmalloc_dma_bounce-for-arm64.patch