From: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
The use of ____cacheline_aligned to ensure a buffer is DMA safe only
enforces the start of the buffer alignment. In this case, sufficient
alignment is already ensured by the use of kzalloc().
____cacheline_aligned does not ensure that no other members of the
structure are placed in the same cacheline after the end of the
buffer marked. Thus to ensure a DMA safe buffer it must be at the end
of the structure.
Whilst here switch from ____cacheline_aligned to
__aligned(ARCH_KMALLOC_MINALIGN) as on some architectures, with variable
sized cacheline lines across their cache hierarchy, require this
greater alignment guarantee for DMA safety. Make this change throughout
the driver as it reduces need for a reader to know about the particular
architecture.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Cc: Lauri Kasanen <cand@xxxxxxx>
--
Only partly compile tested as I don't have a mips toolchain set up.
Would be great to add the stubs to be able to build these drivers
with COMPILE_TEST.
---
drivers/input/joystick/n64joy.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/input/joystick/n64joy.c b/drivers/input/joystick/n64joy.c
index 9dbca366613e..d8c50103c108 100644
--- a/drivers/input/joystick/n64joy.c
+++ b/drivers/input/joystick/n64joy.c
@@ -44,12 +44,12 @@ static const char *n64joy_phys[MAX_CONTROLLERS] = {
};
struct n64joy_priv {
- u64 si_buf[8] ____cacheline_aligned;
struct timer_list timer;
struct mutex n64joy_mutex;
struct input_dev *n64joy_dev[MAX_CONTROLLERS];
u32 __iomem *reg_base;
u8 n64joy_opened;
+ u64 si_buf[8] __aligned(ARCH_KMALLOC_MINALIGN);
};
struct joydata {
@@ -129,7 +129,7 @@ static void n64joy_exec_pif(struct n64joy_priv *priv, const u64 in[8])
local_irq_restore(flags);
}
-static const u64 polldata[] ____cacheline_aligned = {
+static const u64 polldata[] __aligned(ARCH_KMALLOC_MINALIGN) = {
0xff010401ffffffff,
0xff010401ffffffff,
0xff010401ffffffff,
@@ -222,7 +222,7 @@ static void n64joy_close(struct input_dev *dev)
mutex_unlock(&priv->n64joy_mutex);
}
-static const u64 __initconst scandata[] ____cacheline_aligned = {
+static const u64 __initconst scandata[] __aligned(ARCH_KMALLOC_MINALIGN) = {
0xff010300ffffffff,
0xff010300ffffffff,
0xff010300ffffffff,
--
2.38.1
