networking: make skb_push & __skb_push return void pointers

It seems like a historic accident that these return unsigned char *,
and in many places that means casts are required, more often than not.

Make these functions return void * and remove all the casts across
the tree, adding a (u8 *) cast only where the unsigned char pointer
was used directly, all done with the following spatch:

    @@
    expression SKB, LEN;
    typedef u8;
    identifier fn = { skb_push, __skb_push, skb_push_rcsum };
    @@
    - *(fn(SKB, LEN))
    + *(u8 *)fn(SKB, LEN)

    @@
    expression E, SKB, LEN;
    identifier fn = { skb_push, __skb_push, skb_push_rcsum };
    type T;
    @@
    - E = ((T *)(fn(SKB, LEN)))
    + E = fn(SKB, LEN)

    @@
    expression SKB, LEN;
    identifier fn = { skb_push, __skb_push, skb_push_rcsum };
    @@
    - fn(SKB, LEN)[0]
    + *(u8 *)fn(SKB, LEN)

Note that the last part there converts from push(...)[0] to the
more idiomatic *(u8 *)push(...).

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 3 insertions, 4 deletions

diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.c b/drivers/net/wireless/ath/ath9k/hif_usb.c
index 12aa8abbcba4..0d9687a2aa98 100644
--- a/drivers/net/wireless/ath/ath9k/hif_usb.c
+++ b/drivers/net/wireless/ath/ath9k/hif_usb.c
@@ -199,7 +199,7 @@ static int hif_usb_send_mgmt(struct hif_device_usb *hif_dev,
 	cmd->skb = skb;
 	cmd->hif_dev = hif_dev;
 
-	hdr = (__le16 *) skb_push(skb, 4);
+	hdr = skb_push(skb, 4);
 	*hdr++ = cpu_to_le16(skb->len - 4);
 	*hdr++ = cpu_to_le16(ATH_USB_TX_STREAM_MODE_TAG);
 
diff --git a/drivers/net/wireless/ath/ath9k/htc_hst.c b/drivers/net/wireless/ath/ath9k/htc_hst.c
index 9fa8970a1f7d..1bf63a4efb4c 100644
--- a/drivers/net/wireless/ath/ath9k/htc_hst.c
+++ b/drivers/net/wireless/ath/ath9k/htc_hst.c
@@ -26,8 +26,7 @@ static int htc_issue_send(struct htc_target *target, struct sk_buff* skb,
 	struct htc_endpoint *endpoint = &target->endpoint[epid];
 	int status;
 
-	hdr = (struct htc_frame_hdr *)
-		skb_push(skb, sizeof(struct htc_frame_hdr));
+	hdr = skb_push(skb, sizeof(struct htc_frame_hdr));
 	hdr->endpoint_id = epid;
 	hdr->flags = flags;
 	hdr->payload_len = cpu_to_be16(len);
diff --git a/drivers/net/wireless/ath/ath9k/wmi.c b/drivers/net/wireless/ath/ath9k/wmi.c
index c51c69b1ad96..85d09fdef8dc 100644
--- a/drivers/net/wireless/ath/ath9k/wmi.c
+++ b/drivers/net/wireless/ath/ath9k/wmi.c
@@ -277,7 +277,7 @@ static int ath9k_wmi_cmd_issue(struct wmi *wmi,
 	struct wmi_cmd_hdr *hdr;
 	unsigned long flags;
 
-	hdr = (struct wmi_cmd_hdr *) skb_push(skb, sizeof(struct wmi_cmd_hdr));
+	hdr = skb_push(skb, sizeof(struct wmi_cmd_hdr));
 	hdr->command_id = cpu_to_be16(cmd);
 	hdr->seq_no = cpu_to_be16(++wmi->tx_seq_id);