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authorAlexey Brodkin <alexey.brodkin@synopsys.com>2018-10-31 18:25:47 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-11-11 11:40:04 -0800
commita66d972465d15b1d89281258805eb8b47d66bd36 (patch)
treeec2a59ba96a3ab10277197653eb4c76d2a0825cb /drivers/base/devres.c
parent651022382c7f8da46cb4872a545ee1da6d097d2a (diff)
downloadlinux-a66d972465d15b1d89281258805eb8b47d66bd36.tar.bz2
devres: Align data[] to ARCH_KMALLOC_MINALIGN
Initially we bumped into problem with 32-bit aligned atomic64_t on ARC, see [1]. And then during quite lengthly discussion Peter Z. mentioned ARCH_KMALLOC_MINALIGN which IMHO makes perfect sense. If allocation is done by plain kmalloc() obtained buffer will be ARCH_KMALLOC_MINALIGN aligned and then why buffer obtained via devm_kmalloc() should have any other alignment? This way we at least get the same behavior for both types of allocation. [1] http://lists.infradead.org/pipermail/linux-snps-arc/2018-July/004009.html [2] http://lists.infradead.org/pipermail/linux-snps-arc/2018-July/004036.html Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: David Laight <David.Laight@ACULAB.COM> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Greg KH <greg@kroah.com> Cc: <stable@vger.kernel.org> # 4.8+ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base/devres.c')
-rw-r--r--drivers/base/devres.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/drivers/base/devres.c b/drivers/base/devres.c
index 4aaf00d2098b..e038e2b3b7ea 100644
--- a/drivers/base/devres.c
+++ b/drivers/base/devres.c
@@ -26,8 +26,14 @@ struct devres_node {
struct devres {
struct devres_node node;
- /* -- 3 pointers */
- unsigned long long data[]; /* guarantee ull alignment */
+ /*
+ * Some archs want to perform DMA into kmalloc caches
+ * and need a guaranteed alignment larger than
+ * the alignment of a 64-bit integer.
+ * Thus we use ARCH_KMALLOC_MINALIGN here and get exactly the same
+ * buffer alignment as if it was allocated by plain kmalloc().
+ */
+ u8 __aligned(ARCH_KMALLOC_MINALIGN) data[];
};
struct devres_group {