CAPI: Use atomics for capiminor's datahandle and msgid

The capiminor members datahandle and msgid are incremented outside any
lock, so better do this atomically.

Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 9 deletions

diff --git a/drivers/isdn/capi/capi.c b/drivers/isdn/capi/capi.c
index 9d4750a0aece..08d5a8aa2fec 100644
--- a/drivers/isdn/capi/capi.c
+++ b/drivers/isdn/capi/capi.c
@@ -87,10 +87,10 @@ struct capiminor {
         unsigned int      minor;
         struct dentry *capifs_dentry;
 
-        struct capi20_appl *ap;
-        u32              ncci;
-        u16              datahandle;
-        u16              msgid;
+        struct capi20_appl      *ap;
+        u32                     ncci;
+        atomic_t                datahandle;
+        atomic_t                msgid;
 
         struct tty_port port;
         int                ttyinstop;
@@ -227,7 +227,6 @@ static struct capiminor *capiminor_alloc(struct capi20_appl *ap, u32 ncci)
 
         mp->ap = ap;
         mp->ncci = ncci;
-        mp->msgid = 0;
         INIT_LIST_HEAD(&mp->ackqueue);
         spin_lock_init(&mp->ackqlock);
 
@@ -427,7 +426,7 @@ gen_data_b3_resp_for(struct capiminor *mp, struct sk_buff *skb)
                 capimsg_setu16(s, 2, mp->ap->applid);
                 capimsg_setu8 (s, 4, CAPI_DATA_B3);
                 capimsg_setu8 (s, 5, CAPI_RESP);
-                capimsg_setu16(s, 6, mp->msgid++);
+                capimsg_setu16(s, 6, atomic_inc_return(&mp->msgid));
                 capimsg_setu32(s, 8, mp->ncci);
                 capimsg_setu16(s, 12, datahandle);
         }
@@ -554,7 +553,7 @@ static int handle_minor_send(struct capiminor *mp)
         }
 
         while ((skb = skb_dequeue(&mp->outqueue)) != NULL) {
-                datahandle = mp->datahandle;
+                datahandle = atomic_inc_return(&mp->datahandle);
                 len = (u16)skb->len;
                 skb_push(skb, CAPI_DATA_B3_REQ_LEN);
                 memset(skb->data, 0, CAPI_DATA_B3_REQ_LEN);
@@ -562,7 +561,7 @@ static int handle_minor_send(struct capiminor *mp)
                 capimsg_setu16(skb->data, 2, mp->ap->applid);
                 capimsg_setu8 (skb->data, 4, CAPI_DATA_B3);
                 capimsg_setu8 (skb->data, 5, CAPI_REQ);
-                capimsg_setu16(skb->data, 6, mp->msgid++);
+                capimsg_setu16(skb->data, 6, atomic_inc_return(&mp->msgid));
                 capimsg_setu32(skb->data, 8, mp->ncci); /* NCCI */
                 capimsg_setu32(skb->data, 12, (u32)(long)skb->data);/* Data32 */
                 capimsg_setu16(skb->data, 16, len);     /* Data length */
@@ -577,7 +576,6 @@ static int handle_minor_send(struct capiminor *mp)
                 }
                 errcode = capi20_put_message(mp->ap, skb);
                 if (errcode == CAPI_NOERROR) {
-                        mp->datahandle++;
                         count++;
                         mp->outbytes -= len;
 #ifdef _DEBUG_DATAFLOW