Phonet: cleanup pipe enable socket option

The current code works like this:

  int garbage, status;
  socklen_t len = sizeof(status);

  /* enable pipe */
  setsockopt(fd, SOL_PNPIPE, PNPIPE_ENABLE, &garbage, sizeof(garbage));
  /* disable pipe */
  setsockopt(fd, SOL_PNPIPE, PNPIPE_DISABLE, &garbage, sizeof(garbage));
  /* get status */
  getsockopt(fd, SOL_PNPIPE, PNPIPE_INQ, &status, &len);

...which does not follow the usual socket option pattern. This patch
merges all three "options" into a single gettable&settable option,
before Linux 2.6.37 gets out:

  int status;
  socklen_t len = sizeof(status);

  /* enable pipe */
  status = 1;
  setsockopt(fd, SOL_PNPIPE, PNPIPE_ENABLE, &status, sizeof(status));
  /* disable pipe */
  status = 0;
  setsockopt(fd, SOL_PNPIPE, PNPIPE_ENABLE, &status, sizeof(status));
  /* get status */
  getsockopt(fd, SOL_PNPIPE, PNPIPE_ENABLE, &status, &len);

This also fixes the error code from EFAULT to ENOTCONN.

Signed-off-by: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
Cc: Kumar Sanghvi <kumar.sanghvi@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/phonet.h b/include/linux/phonet.h
index 96f5625..e27cbf9 100644
--- a/include/linux/phonet.h
+++ b/include/linux/phonet.h
@@ -38,9 +38,8 @@
 #define PNPIPE_IFINDEX		2
 #define PNPIPE_CREATE           3
 #define PNPIPE_ENABLE           4
-#define PNPIPE_DISABLE          5
+/* unused slot */
 #define PNPIPE_DESTROY          6
-#define PNPIPE_INQ              7
 
 #define PNADDR_ANY		0
 #define PNADDR_BROADCAST	0xFC