[PATCH] siox: use kzalloc_flex

[Rosen Penev <rosenp@gmail.com>]

Use the proper function to allocate a struct with a flexible array
member.

Add __counted_by for extra runtime analysis. Add counting variable
assignment as required by __counted_by.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 drivers/siox/siox-core.c | 5 +++--
 drivers/siox/siox.h      | 3 ++-
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/siox/siox-core.c b/drivers/siox/siox-core.c
index 3e8f3b6a4555..b87e2a12d640 100644
--- a/drivers/siox/siox-core.c
+++ b/drivers/siox/siox-core.c
@@ -689,10 +689,11 @@ struct siox_master *siox_master_alloc(struct device *dev,
 	if (!dev)
 		return NULL;
 
-	smaster = kzalloc(sizeof(*smaster) + size, GFP_KERNEL);
+	smaster = kzalloc_flex(*smaster, buf, size);
 	if (!smaster)
 		return NULL;
 
+	smaster->buf_len = size;
 	device_initialize(&smaster->dev);
 
 	smaster->busno = -1;
@@ -854,7 +855,7 @@ static struct siox_device *siox_device_add(struct siox_master *smaster,
 		}
 
 		smaster->buf_len = buf_len;
-		smaster->buf = buf;
+		memcpy(smaster->buf, buf, buf_len);
 	}
 
 	ret = device_register(&sdevice->dev);
diff --git a/drivers/siox/siox.h b/drivers/siox/siox.h
index 513f2c8312f7..e6809fcafa0f 100644
--- a/drivers/siox/siox.h
+++ b/drivers/siox/siox.h
@@ -27,11 +27,12 @@ struct siox_master {
 
 	size_t setbuf_len, getbuf_len;
 	size_t buf_len;
-	u8 *buf;
 	u8 status;
 
 	unsigned long last_poll;
 	struct task_struct *poll_thread;
+
+	u8 buf[] __counted_by(buf_len);
 };
 
 static inline void *siox_master_get_devdata(struct siox_master *smaster)
-- 
2.53.0