[ISDN] capidrv: address two longstanding warnings

* change #warning to a code comment

* add comment and special ifdef'd 64-bit code for a situation where
  we must store a pointer into a CAPI field 'Data', which is fixed by
  the interface at 32 bits.

Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Acked-by: Karsten Keil <kkeil@suse.de>

1 files changed, 23 insertions, 2 deletions

diff --git a/drivers/isdn/capi/capidrv.c b/drivers/isdn/capi/capidrv.c
index 476012b6dfac..48c1775ef5b3 100644
--- a/drivers/isdn/capi/capidrv.c
+++ b/drivers/isdn/capi/capidrv.c
@@ -1843,6 +1843,7 @@ static int if_sendbuf(int id, int channel, int doack, struct sk_buff *skb)
         int msglen;
         u16 errcode;
         u16 datahandle;
+        u32 data;
 
         if (!card) {
                 printk(KERN_ERR "capidrv: if_sendbuf called with invalid driverId %d!\n",
@@ -1860,9 +1861,26 @@ static int if_sendbuf(int id, int channel, int doack, struct sk_buff *skb)
                 return 0;
         }
         datahandle = nccip->datahandle;
+
+        /*
+         * Here we copy pointer skb->data into the 32-bit 'Data' field.
+         * The 'Data' field is not used in practice in linux kernel
+         * (neither in 32 or 64 bit), but should have some value,
+         * since a CAPI message trace will display it.
+         *
+         * The correct value in the 32 bit case is the address of the
+         * data, in 64 bit it makes no sense, we use 0 there.
+         */
+
+#ifdef CONFIG_64BIT
+        data = 0;
+#else
+        data = (unsigned long) skb->data;
+#endif
+
         capi_fill_DATA_B3_REQ(&sendcmsg, global.ap.applid, card->msgid++,
                               nccip->ncci,      /* adr */
-                              (u32) skb->data,  /* Data */
+                              data,             /* Data */
                               skb->len,         /* DataLength */
                               datahandle,       /* DataHandle */
                               0 /* Flags */
@@ -2123,7 +2141,10 @@ static int capidrv_delcontr(u16 contr)
                 printk(KERN_ERR "capidrv: delcontr: no contr %u\n", contr);
                 return -1;
         }
-        #warning FIXME: maybe a race condition the card should be removed here from global list /kkeil
+
+        /* FIXME: maybe a race condition the card should be removed
+         * here from global list /kkeil
+         */
         spin_unlock_irqrestore(&global_lock, flags);
 
         del_timer(&card->listentimer);