Big polling(4) cleanup.

o Axe poll in trap.

o Axe IFF_POLLING flag from if_flags.

o Rework revision 1.21 (Giant removal), in such a way that
  poll_mtx is not dropped during call to polling handler.
  This fixes problem with idle polling.

o Make registration and deregistration from polling in a
  functional way, insted of next tick/interrupt.

o Obsolete kern.polling.enable. Polling is turned on/off
  with ifconfig.

Detailed kern_poll.c changes:
  - Remove polling handler flags, introduced in 1.21. The are not
    needed now.
  - Forget and do not check if_flags, if_capenable and if_drv_flags.
  - Call all registered polling handlers unconditionally.
  - Do not drop poll_mtx, when entering polling handlers.
  - In ether_poll() NET_LOCK_GIANT prior to locking poll_mtx.
  - In netisr_poll() axe the block, where polling code asks drivers
    to unregister.
  - In netisr_poll() and ether_poll() do polling always, if any
    handlers are present.
  - In ether_poll_[de]register() remove a lot of error hiding code. Assert
    that arguments are correct, instead.
  - In ether_poll_[de]register() use standard return values in case of
    error or success.
  - Introduce poll_switch() that is a sysctl handler for kern.polling.enable.
    poll_switch() goes through interface list and enabled/disables polling.
    A message that kern.polling.enable is deprecated is printed.

Detailed driver changes:
  - On attach driver announces IFCAP_POLLING in if_capabilities, but
    not in if_capenable.
  - On detach driver calls ether_poll_deregister() if polling is enabled.
  - In polling handler driver obtains its lock and checks IFF_DRV_RUNNING
    flag. If there is no, then unlocks and returns.
  - In ioctl handler driver checks for IFCAP_POLLING flag requested to
    be set or cleared. Driver first calls ether_poll_[de]register(), then
    obtains driver lock and [dis/en]ables interrupts.
  - In interrupt handler driver checks IFCAP_POLLING flag in if_capenable.
    If present, then returns.This is important to protect from spurious
    interrupts.

Reviewed by:	ru, sam, jhb

2 files changed, 3 insertions, 4 deletions

diff --git a/sys/net/if.h b/sys/net/if.h
index 43173ce..460f374 100644
--- a/sys/net/if.h
+++ b/sys/net/if.h
@@ -148,7 +148,7 @@ struct if_data {
 #define	IFF_LINK2	0x4000		/* per link layer defined bit */
 #define	IFF_ALTPHYS	IFF_LINK2	/* use alternate physical connection */
 #define	IFF_MULTICAST	0x8000		/* (i) supports multicast */
-#define	IFF_POLLING	0x10000		/* (n) Interface is in polling mode. */
+/*			0x10000		*/
 #define	IFF_PPROMISC	0x20000		/* (n) user-requested promisc mode */
 #define	IFF_MONITOR	0x40000		/* (n) user-requested monitor mode */
 #define	IFF_STATICARP	0x80000		/* (n) static ARP */
@@ -166,8 +166,7 @@ struct if_data {
 /* flags set internally only: */
 #define	IFF_CANTCHANGE \
 	(IFF_BROADCAST|IFF_POINTOPOINT|IFF_DRV_RUNNING|IFF_DRV_OACTIVE|\
-	    IFF_SIMPLEX|IFF_MULTICAST|IFF_ALLMULTI|IFF_SMART|IFF_PROMISC|\
-	    IFF_POLLING)
+	    IFF_SIMPLEX|IFF_MULTICAST|IFF_ALLMULTI|IFF_SMART|IFF_PROMISC)
 
 /*
  * Values for if_link_state.
diff --git a/sys/net/if_var.h b/sys/net/if_var.h
index 1f0431e..783ddd8 100644
--- a/sys/net/if_var.h
+++ b/sys/net/if_var.h
@@ -660,7 +660,7 @@ void	if_deregister_com_alloc(u_char type);
     LLADDR((struct sockaddr_dl *) ifaddr_byindex((ifp)->if_index)->ifa_addr)
 
 #ifdef DEVICE_POLLING
-enum poll_cmd {	POLL_ONLY, POLL_AND_CHECK_STATUS, POLL_DEREGISTER };
+enum poll_cmd {	POLL_ONLY, POLL_AND_CHECK_STATUS };
 
 typedef	void poll_handler_t(struct ifnet *ifp, enum poll_cmd cmd, int count);
 int    ether_poll_register(poll_handler_t *h, struct ifnet *ifp);