Currently the I/O buffer is allocated part of the device status
structure, potentially sharing the same cache line with other members
in this structure.
Allocate the buffer separately, to avoid the I/O operations corrupting
the device status structure due to cache line sharing.
Compiled tested only as I don't have access to hardware.
Signed-off-by: Octavian Purdila <octavian.purdila@xxxxxxxxx>
---
drivers/mfd/viperboard.c | 8 ++++++++
include/linux/mfd/viperboard.h | 2 +-
2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/mfd/viperboard.c b/drivers/mfd/viperboard.c
index e00f534..5f62f4e 100644
--- a/drivers/mfd/viperboard.c
+++ b/drivers/mfd/viperboard.c
@@ -64,6 +64,12 @@ static int vprbrd_probe(struct usb_interface *interface,
return -ENOMEM;
}
+ vb->buf = kzalloc(sizeof(struct vprbrd_i2c_write_msg), GFP_KERNEL);
+ if (vb->buf == NULL) {
+ ret = -ENOMEM;
+ goto error;
+ }
+
mutex_init(&vb->lock);
vb->usb_dev = usb_get_dev(interface_to_usbdev(interface));
@@ -105,6 +111,7 @@ static int vprbrd_probe(struct usb_interface *interface,
error:
if (vb) {
usb_put_dev(vb->usb_dev);
+ kfree(vb->buf);
kfree(vb);
}
@@ -118,6 +125,7 @@ static void vprbrd_disconnect(struct usb_interface *interface)
mfd_remove_devices(&interface->dev);
usb_set_intfdata(interface, NULL);
usb_put_dev(vb->usb_dev);
+ kfree(vb->buf);
kfree(vb);
dev_dbg(&interface->dev, "disconnected\n");
diff --git a/include/linux/mfd/viperboard.h b/include/linux/mfd/viperboard.h
index 1934528..af928d0 100644
--- a/include/linux/mfd/viperboard.h
+++ b/include/linux/mfd/viperboard.h
@@ -103,7 +103,7 @@ struct vprbrd_i2c_addr_msg {
struct vprbrd {
struct usb_device *usb_dev; /* the usb device for this device */
struct mutex lock;
- u8 buf[sizeof(struct vprbrd_i2c_write_msg)];
+ u8 *buf;
struct platform_device pdev;
};
--
1.9.1
--
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