[PATCH 2/6] Bluetooth: coredump: Allow drivers to pad dump header to fixed size

[Zijun Hu]

To let a driver easily separate header and data in the generated
coredump, allow a vendor driver to pad its header to a fixed size by:
 - exposing MAX_HCI_DEVCD_HDR_SIZE as the max header size
 - exposing HCI_DEVCD_HDR_END as the header-ending marker

Signed-off-by: Zijun Hu <zijun.hu@xxxxxxxxxxxxxxxx>
---
 include/net/bluetooth/coredump.h | 4 ++++
 net/bluetooth/coredump.c         | 7 ++-----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/include/net/bluetooth/coredump.h b/include/net/bluetooth/coredump.h
index ab85a6adfffd..b668277bdb76 100644
--- a/include/net/bluetooth/coredump.h
+++ b/include/net/bluetooth/coredump.h
@@ -8,6 +8,10 @@
 
 #define DEVCOREDUMP_TIMEOUT	msecs_to_jiffies(10000)	/* 10 sec */
 
+/* total size shared by coredump and driver's dmp_hdr() */
+#define MAX_HCI_DEVCD_HDR_SIZE	512
+#define HCI_DEVCD_HDR_END	"--- Start dump ---\n"
+
 typedef void (*coredump_t)(struct hci_dev *hdev);
 typedef void (*dmp_hdr_t)(struct hci_dev *hdev, struct sk_buff *skb);
 typedef void (*notify_change_t)(struct hci_dev *hdev, int state);
diff --git a/net/bluetooth/coredump.c b/net/bluetooth/coredump.c
index 3d4c2194ef43..c77bf511679d 100644
--- a/net/bluetooth/coredump.c
+++ b/net/bluetooth/coredump.c
@@ -34,8 +34,6 @@ struct hci_devcoredump_skb_pattern {
 		   hci_dmp_cb(skb)->pkt_type, \
 		   hci_devcd_state_name(hdev->dump.state))
 
-#define MAX_DEVCOREDUMP_HDR_SIZE	512	/* bytes */
-
 static int hci_devcd_update_hdr_state(char *buf, size_t size, int state)
 {
 	int len = 0;
@@ -63,7 +61,6 @@ static int hci_devcd_update_state(struct hci_dev *hdev, int state)
 
 static int hci_devcd_mkheader(struct hci_dev *hdev, struct sk_buff *skb)
 {
-	char dump_start[] = "--- Start dump ---\n";
 	char hdr[80];
 	int hdr_len;
 
@@ -74,7 +71,7 @@ static int hci_devcd_mkheader(struct hci_dev *hdev, struct sk_buff *skb)
 	if (hdev->dump.dmp_hdr)
 		hdev->dump.dmp_hdr(hdev, skb);
 
-	skb_put_data(skb, dump_start, strlen(dump_start));
+	skb_put_data(skb, HCI_DEVCD_HDR_END, strlen(HCI_DEVCD_HDR_END));
 
 	return skb->len;
 }
@@ -154,7 +151,7 @@ static int hci_devcd_prepare(struct hci_dev *hdev, u32 dump_size)
 	int dump_hdr_size;
 	int err = 0;
 
-	skb = alloc_skb(MAX_DEVCOREDUMP_HDR_SIZE, GFP_ATOMIC);
+	skb = alloc_skb(MAX_HCI_DEVCD_HDR_SIZE, GFP_ATOMIC);
 	if (!skb)
 		return -ENOMEM;
 

-- 
2.34.1