[net-next-2.6.git] / include / linux / skbuff.h

/*
 *	Definitions for the 'struct sk_buff' memory handlers.
 *
 *	Authors:
 *		Alan Cox, <gw4pts@gw4pts.ampr.org>
 *		Florian La Roche, <rzsfl@rz.uni-sb.de>
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	as published by the Free Software Foundation; either version
 *	2 of the License, or (at your option) any later version.
 */

#ifndef _LINUX_SKBUFF_H
#define _LINUX_SKBUFF_H

#include <linux/kernel.h>
#include <linux/compiler.h>
#include <linux/time.h>
#include <linux/cache.h>

#include <asm/atomic.h>
#include <asm/types.h>
#include <linux/spinlock.h>
#include <linux/net.h>
#include <linux/textsearch.h>
#include <net/checksum.h>
#include <linux/rcupdate.h>
#include <linux/dmaengine.h>
#include <linux/hrtimer.h>

#define HAVE_ALLOC_SKB		/* For the drivers to know */
#define HAVE_ALIGNABLE_SKB	/* Ditto 8)		   */

#define CHECKSUM_NONE 0
#define CHECKSUM_PARTIAL 1
#define CHECKSUM_UNNECESSARY 2
#define CHECKSUM_COMPLETE 3

#define SKB_DATA_ALIGN(X)	(((X) + (SMP_CACHE_BYTES - 1)) & \
				 ~(SMP_CACHE_BYTES - 1))
#define SKB_WITH_OVERHEAD(X)	\
	(((X) - sizeof(struct skb_shared_info)) & \
	 ~(SMP_CACHE_BYTES - 1))
#define SKB_MAX_ORDER(X, ORDER) \
	SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
#define SKB_MAX_HEAD(X)		(SKB_MAX_ORDER((X), 0))
#define SKB_MAX_ALLOC		(SKB_MAX_ORDER(0, 2))

/* A. Checksumming of received packets by device.
 *
 *	NONE: device failed to checksum this packet.
 *		skb->csum is undefined.
 *
 *	UNNECESSARY: device parsed packet and wouldbe verified checksum.
 *		skb->csum is undefined.
 *	      It is bad option, but, unfortunately, many of vendors do this.
 *	      Apparently with secret goal to sell you new device, when you
 *	      will add new protocol to your host. F.e. IPv6. 8)
 *
 *	COMPLETE: the most generic way. Device supplied checksum of _all_
 *	    the packet as seen by netif_rx in skb->csum.
 *	    NOTE: Even if device supports only some protocols, but
 *	    is able to produce some skb->csum, it MUST use COMPLETE,
 *	    not UNNECESSARY.
 *
 * B. Checksumming on output.
 *
 *	NONE: skb is checksummed by protocol or csum is not required.
 *
 *	PARTIAL: device is required to csum packet as seen by hard_start_xmit
 *	from skb->transport_header to the end and to record the checksum
 *	at skb->transport_header + skb->csum.
 *
 *	Device must show its capabilities in dev->features, set
 *	at device setup time.
 *	NETIF_F_HW_CSUM	- it is clever device, it is able to checksum
 *			  everything.
 *	NETIF_F_NO_CSUM - loopback or reliable single hop media.
 *	NETIF_F_IP_CSUM - device is dumb. It is able to csum only
 *			  TCP/UDP over IPv4. Sigh. Vendors like this
 *			  way by an unknown reason. Though, see comment above
 *			  about CHECKSUM_UNNECESSARY. 8)
 *
 *	Any questions? No questions, good. 		--ANK
 */

struct net_device;

#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
struct nf_conntrack {
	atomic_t use;
};
#endif

#ifdef CONFIG_BRIDGE_NETFILTER
struct nf_bridge_info {
	atomic_t use;
	struct net_device *physindev;
	struct net_device *physoutdev;
#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
	struct net_device *netoutdev;
#endif
	unsigned int mask;
	unsigned long data[32 / sizeof(unsigned long)];
};
#endif

struct sk_buff_head {
	/* These two members must be first. */
	struct sk_buff	*next;
	struct sk_buff	*prev;

	__u32		qlen;
	spinlock_t	lock;
};

struct sk_buff;

/* To allow 64K frame to be packed as single skb without frag_list */
#define MAX_SKB_FRAGS (65536/PAGE_SIZE + 2)

typedef struct skb_frag_struct skb_frag_t;

struct skb_frag_struct {
	struct page *page;
	__u16 page_offset;
	__u16 size;
};

/* This data is invariant across clones and lives at
 * the end of the header data, ie. at skb->end.
 */
struct skb_shared_info {
	atomic_t	dataref;
	unsigned short	nr_frags;
	unsigned short	gso_size;
	/* Warning: this field is not always filled in (UFO)! */
	unsigned short	gso_segs;
	unsigned short  gso_type;
	__be32          ip6_frag_id;
	struct sk_buff	*frag_list;
	skb_frag_t	frags[MAX_SKB_FRAGS];
};

/* We divide dataref into two halves.  The higher 16 bits hold references
 * to the payload part of skb->data.  The lower 16 bits hold references to
 * the entire skb->data.  It is up to the users of the skb to agree on
 * where the payload starts.
 *
 * All users must obey the rule that the skb->data reference count must be
 * greater than or equal to the payload reference count.
 *
 * Holding a reference to the payload part means that the user does not
 * care about modifications to the header part of skb->data.
 */
#define SKB_DATAREF_SHIFT 16
#define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)


enum {
	SKB_FCLONE_UNAVAILABLE,
	SKB_FCLONE_ORIG,
	SKB_FCLONE_CLONE,
};

enum {
	SKB_GSO_TCPV4 = 1 << 0,
	SKB_GSO_UDP = 1 << 1,

	/* This indicates the skb is from an untrusted source. */
	SKB_GSO_DODGY = 1 << 2,

	/* This indicates the tcp segment has CWR set. */
	SKB_GSO_TCP_ECN = 1 << 3,

	SKB_GSO_TCPV6 = 1 << 4,
};

#if BITS_PER_LONG > 32
#define NET_SKBUFF_DATA_USES_OFFSET 1
#endif

#ifdef NET_SKBUFF_DATA_USES_OFFSET
typedef unsigned int sk_buff_data_t;
#else
typedef unsigned char *sk_buff_data_t;
#endif

/** 
 *	struct sk_buff - socket buffer
 *	@next: Next buffer in list
 *	@prev: Previous buffer in list
 *	@sk: Socket we are owned by
 *	@tstamp: Time we arrived
 *	@dev: Device we arrived on/are leaving by
 *	@iif: ifindex of device we arrived on
 *	@h: Transport layer header
 *	@network_header: Network layer header
 *	@mac_header: Link layer header
 *	@dst: destination entry
 *	@sp: the security path, used for xfrm
 *	@cb: Control buffer. Free for use by every layer. Put private vars here
 *	@len: Length of actual data
 *	@data_len: Data length
 *	@mac_len: Length of link layer header
 *	@csum: Checksum
 *	@local_df: allow local fragmentation
 *	@cloned: Head may be cloned (check refcnt to be sure)
 *	@nohdr: Payload reference only, must not modify header
 *	@pkt_type: Packet class
 *	@fclone: skbuff clone status
 *	@ip_summed: Driver fed us an IP checksum
 *	@priority: Packet queueing priority
 *	@users: User count - see {datagram,tcp}.c
 *	@protocol: Packet protocol from driver
 *	@truesize: Buffer size 
 *	@head: Head of buffer
 *	@data: Data head pointer
 *	@tail: Tail pointer
 *	@end: End pointer
 *	@destructor: Destruct function
 *	@mark: Generic packet mark
 *	@nfct: Associated connection, if any
 *	@ipvs_property: skbuff is owned by ipvs
 *	@nfctinfo: Relationship of this skb to the connection
 *	@nfct_reasm: netfilter conntrack re-assembly pointer
 *	@nf_bridge: Saved data about a bridged frame - see br_netfilter.c
 *	@tc_index: Traffic control index
 *	@tc_verd: traffic control verdict
 *	@dma_cookie: a cookie to one of several possible DMA operations
 *		done by skb DMA functions
 *	@secmark: security marking
 */

struct sk_buff {
	/* These two members must be first. */
	struct sk_buff		*next;
	struct sk_buff		*prev;

	struct sock		*sk;
	ktime_t			tstamp;
	struct net_device	*dev;
	int			iif;
	/* 4 byte hole on 64 bit*/

	struct  dst_entry	*dst;
	struct	sec_path	*sp;

	/*
	 * This is the control buffer. It is free to use for every
	 * layer. Please put your private variables there. If you
	 * want to keep them across layers you have to do a skb_clone()
	 * first. This is owned by whoever has the skb queued ATM.
	 */
	char			cb[48];

	unsigned int		len,
				data_len,
				mac_len;
	union {
		__wsum		csum;
		__u32		csum_offset;
	};
	__u32			priority;
	__u8			local_df:1,
				cloned:1,
				ip_summed:2,
				nohdr:1,
				nfctinfo:3;
	__u8			pkt_type:3,
				fclone:2,
				ipvs_property:1;
	__be16			protocol;

	void			(*destructor)(struct sk_buff *skb);
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
	struct nf_conntrack	*nfct;
	struct sk_buff		*nfct_reasm;
#endif
#ifdef CONFIG_BRIDGE_NETFILTER
	struct nf_bridge_info	*nf_bridge;
#endif
#ifdef CONFIG_NET_SCHED
	__u16			tc_index;	/* traffic control index */
#ifdef CONFIG_NET_CLS_ACT
	__u16			tc_verd;	/* traffic control verdict */
#endif
#endif
#ifdef CONFIG_NET_DMA
	dma_cookie_t		dma_cookie;
#endif
#ifdef CONFIG_NETWORK_SECMARK
	__u32			secmark;
#endif

	__u32			mark;

	sk_buff_data_t		transport_header;
	sk_buff_data_t		network_header;
	sk_buff_data_t		mac_header;
	/* These elements must be at the end, see alloc_skb() for details.  */
	sk_buff_data_t		tail;
	sk_buff_data_t		end;
	unsigned char		*head,
				*data;
	unsigned int		truesize;
	atomic_t		users;
};

#ifdef __KERNEL__
/*
 *	Handling routines are only of interest to the kernel
 */
#include <linux/slab.h>

#include <asm/system.h>
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Definitions for the 'struct sk_buff' memory handlers.
	3	*
	4	* Authors:
	5	* Alan Cox, <gw4pts@gw4pts.ampr.org>
	6	* Florian La Roche, <rzsfl@rz.uni-sb.de>
	7	*
	8	* This program is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU General Public License
	10	* as published by the Free Software Foundation; either version
	11	* 2 of the License, or (at your option) any later version.
	12	*/
	13
	14	#ifndef _LINUX_SKBUFF_H
	15	#define _LINUX_SKBUFF_H
	16
1da177e4 LT	17	#include <linux/kernel.h>
	18	#include <linux/compiler.h>
	19	#include <linux/time.h>
	20	#include <linux/cache.h>
	21
	22	#include <asm/atomic.h>
	23	#include <asm/types.h>
	24	#include <linux/spinlock.h>
1da177e4	25	#include <linux/net.h>
3fc7e8a6	26	#include <linux/textsearch.h>
1da177e4	27	#include <net/checksum.h>
a80958f4	28	#include <linux/rcupdate.h>
97fc2f08	29	#include <linux/dmaengine.h>
b7aa0bf7	30	#include <linux/hrtimer.h>
1da177e4 LT	31
	32	#define HAVE_ALLOC_SKB /* For the drivers to know */
	33	#define HAVE_ALIGNABLE_SKB /* Ditto 8) */
1da177e4 LT	34
1da177e4 LT	35	#define CHECKSUM_NONE 0
84fa7933	36	#define CHECKSUM_PARTIAL 1
1da177e4	37	#define CHECKSUM_UNNECESSARY 2
84fa7933	38	#define CHECKSUM_COMPLETE 3
1da177e4 LT	39
	40	#define SKB_DATA_ALIGN(X) (((X) + (SMP_CACHE_BYTES - 1)) & \
	41	~(SMP_CACHE_BYTES - 1))
fc910a27 DM	42	#define SKB_WITH_OVERHEAD(X) \
	43	(((X) - sizeof(struct skb_shared_info)) & \
	44	~(SMP_CACHE_BYTES - 1))
	45	#define SKB_MAX_ORDER(X, ORDER) \
	46	SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
1da177e4 LT	47	#define SKB_MAX_HEAD(X) (SKB_MAX_ORDER((X), 0))
	48	#define SKB_MAX_ALLOC (SKB_MAX_ORDER(0, 2))
	49
	50	/* A. Checksumming of received packets by device.
	51	*
	52	* NONE: device failed to checksum this packet.
	53	* skb->csum is undefined.
	54	*
	55	* UNNECESSARY: device parsed packet and wouldbe verified checksum.
	56	* skb->csum is undefined.
	57	* It is bad option, but, unfortunately, many of vendors do this.
	58	* Apparently with secret goal to sell you new device, when you
	59	* will add new protocol to your host. F.e. IPv6. 8)
	60	*
84fa7933	61	* COMPLETE: the most generic way. Device supplied checksum of _all_
1da177e4 LT	62	* the packet as seen by netif_rx in skb->csum.
1da177e4 LT	63	* NOTE: Even if device supports only some protocols, but
84fa7933	64	* is able to produce some skb->csum, it MUST use COMPLETE,
1da177e4 LT	65	* not UNNECESSARY.
	66	*
	67	* B. Checksumming on output.
	68	*
	69	* NONE: skb is checksummed by protocol or csum is not required.
	70	*
84fa7933	71	* PARTIAL: device is required to csum packet as seen by hard_start_xmit
b0e380b1 ACM	72	* from skb->transport_header to the end and to record the checksum
b0e380b1 ACM	73	* at skb->transport_header + skb->csum.
1da177e4 LT	74	*
	75	* Device must show its capabilities in dev->features, set
	76	* at device setup time.
	77	* NETIF_F_HW_CSUM - it is clever device, it is able to checksum
	78	* everything.
	79	* NETIF_F_NO_CSUM - loopback or reliable single hop media.
	80	* NETIF_F_IP_CSUM - device is dumb. It is able to csum only
	81	* TCP/UDP over IPv4. Sigh. Vendors like this
	82	* way by an unknown reason. Though, see comment above
	83	* about CHECKSUM_UNNECESSARY. 8)
	84	*
	85	* Any questions? No questions, good. --ANK
	86	*/
	87
1da177e4 LT	88	struct net_device;
1da177e4 LT	89
5f79e0f9	90	#if defined(CONFIG_NF_CONNTRACK) \|\| defined(CONFIG_NF_CONNTRACK_MODULE)
1da177e4 LT	91	struct nf_conntrack {
1da177e4 LT	92	atomic_t use;
1da177e4	93	};
5f79e0f9	94	#endif
1da177e4 LT	95
	96	#ifdef CONFIG_BRIDGE_NETFILTER
	97	struct nf_bridge_info {
	98	atomic_t use;
	99	struct net_device *physindev;
	100	struct net_device *physoutdev;
	101	#if defined(CONFIG_VLAN_8021Q) \|\| defined(CONFIG_VLAN_8021Q_MODULE)
	102	struct net_device *netoutdev;
	103	#endif
	104	unsigned int mask;
	105	unsigned long data[32 / sizeof(unsigned long)];
	106	};
	107	#endif
	108
1da177e4 LT	109	struct sk_buff_head {
	110	/* These two members must be first. */
	111	struct sk_buff *next;
	112	struct sk_buff *prev;
	113
	114	__u32 qlen;
	115	spinlock_t lock;
	116	};
	117
	118	struct sk_buff;
	119
	120	/* To allow 64K frame to be packed as single skb without frag_list */
	121	#define MAX_SKB_FRAGS (65536/PAGE_SIZE + 2)
	122
	123	typedef struct skb_frag_struct skb_frag_t;
	124
	125	struct skb_frag_struct {
	126	struct page *page;
	127	__u16 page_offset;
	128	__u16 size;
	129	};
	130
	131	/* This data is invariant across clones and lives at
	132	* the end of the header data, ie. at skb->end.
	133	*/
	134	struct skb_shared_info {
	135	atomic_t dataref;
4947d3ef	136	unsigned short nr_frags;
7967168c HX	137	unsigned short gso_size;
	138	/* Warning: this field is not always filled in (UFO)! */
	139	unsigned short gso_segs;
	140	unsigned short gso_type;
ae08e1f0	141	__be32 ip6_frag_id;
1da177e4 LT	142	struct sk_buff *frag_list;
	143	skb_frag_t frags[MAX_SKB_FRAGS];
	144	};
	145
	146	/* We divide dataref into two halves. The higher 16 bits hold references
	147	* to the payload part of skb->data. The lower 16 bits hold references to
	148	* the entire skb->data. It is up to the users of the skb to agree on
	149	* where the payload starts.
	150	*
	151	* All users must obey the rule that the skb->data reference count must be
	152	* greater than or equal to the payload reference count.
	153	*
	154	* Holding a reference to the payload part means that the user does not
	155	* care about modifications to the header part of skb->data.
	156	*/
	157	#define SKB_DATAREF_SHIFT 16
	158	#define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
	159
d179cd12 DM	160
	161	enum {
	162	SKB_FCLONE_UNAVAILABLE,
	163	SKB_FCLONE_ORIG,
	164	SKB_FCLONE_CLONE,
	165	};
	166
7967168c HX	167	enum {
7967168c HX	168	SKB_GSO_TCPV4 = 1 << 0,
f83ef8c0	169	SKB_GSO_UDP = 1 << 1,
576a30eb HX	170
	171	/* This indicates the skb is from an untrusted source. */
	172	SKB_GSO_DODGY = 1 << 2,
b0da8537 MC	173
b0da8537 MC	174	/* This indicates the tcp segment has CWR set. */
f83ef8c0 HX	175	SKB_GSO_TCP_ECN = 1 << 3,
	176
	177	SKB_GSO_TCPV6 = 1 << 4,
7967168c HX	178	};
7967168c HX	179
2e07fa9c ACM	180	#if BITS_PER_LONG > 32
	181	#define NET_SKBUFF_DATA_USES_OFFSET 1
	182	#endif
	183
	184	#ifdef NET_SKBUFF_DATA_USES_OFFSET
	185	typedef unsigned int sk_buff_data_t;
	186	#else
	187	typedef unsigned char *sk_buff_data_t;
	188	#endif
	189
1da177e4 LT	190	/**
	191	* struct sk_buff - socket buffer
	192	* @next: Next buffer in list
	193	* @prev: Previous buffer in list
1da177e4	194	* @sk: Socket we are owned by
325ed823	195	* @tstamp: Time we arrived
1da177e4	196	* @dev: Device we arrived on/are leaving by
c01003c2	197	* @iif: ifindex of device we arrived on
1da177e4	198	* @h: Transport layer header
b0e380b1 ACM	199	* @network_header: Network layer header
b0e380b1 ACM	200	* @mac_header: Link layer header
67be2dd1 MW	201	* @dst: destination entry
67be2dd1 MW	202	* @sp: the security path, used for xfrm
1da177e4 LT	203	* @cb: Control buffer. Free for use by every layer. Put private vars here
	204	* @len: Length of actual data
	205	* @data_len: Data length
	206	* @mac_len: Length of link layer header
	207	* @csum: Checksum
67be2dd1	208	* @local_df: allow local fragmentation
1da177e4 LT	209	* @cloned: Head may be cloned (check refcnt to be sure)
	210	* @nohdr: Payload reference only, must not modify header
	211	* @pkt_type: Packet class
c83c2486	212	* @fclone: skbuff clone status
1da177e4 LT	213	* @ip_summed: Driver fed us an IP checksum
	214	* @priority: Packet queueing priority
	215	* @users: User count - see {datagram,tcp}.c
	216	* @protocol: Packet protocol from driver
1da177e4 LT	217	* @truesize: Buffer size
	218	* @head: Head of buffer
	219	* @data: Data head pointer
	220	* @tail: Tail pointer
	221	* @end: End pointer
	222	* @destructor: Destruct function
82e91ffe	223	* @mark: Generic packet mark
1da177e4	224	* @nfct: Associated connection, if any
c83c2486	225	* @ipvs_property: skbuff is owned by ipvs
1da177e4	226	* @nfctinfo: Relationship of this skb to the connection
461ddf3b	227	* @nfct_reasm: netfilter conntrack re-assembly pointer
1da177e4	228	* @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
1da177e4 LT	229	* @tc_index: Traffic control index
1da177e4 LT	230	* @tc_verd: traffic control verdict
f4b8ea78 RD	231	* @dma_cookie: a cookie to one of several possible DMA operations
f4b8ea78 RD	232	* done by skb DMA functions
984bc16c	233	* @secmark: security marking
1da177e4 LT	234	*/
	235
	236	struct sk_buff {
	237	/* These two members must be first. */
	238	struct sk_buff *next;
	239	struct sk_buff *prev;
	240
1da177e4	241	struct sock *sk;
b7aa0bf7	242	ktime_t tstamp;
1da177e4	243	struct net_device *dev;
c01003c2 PM	244	int iif;
c01003c2 PM	245	/* 4 byte hole on 64 bit*/
1da177e4	246
1da177e4 LT	247	struct dst_entry *dst;
	248	struct sec_path *sp;
	249
	250	/*
	251	* This is the control buffer. It is free to use for every
	252	* layer. Please put your private variables there. If you
	253	* want to keep them across layers you have to do a skb_clone()
	254	* first. This is owned by whoever has the skb queued ATM.
	255	*/
3e3850e9	256	char cb[48];
1da177e4 LT	257
	258	unsigned int len,
	259	data_len,
1f61ab5c	260	mac_len;
ff1dcadb AV	261	union {
	262	__wsum csum;
	263	__u32 csum_offset;
	264	};
1da177e4	265	__u32 priority;
1cbb3380 TG	266	__u8 local_df:1,
	267	cloned:1,
	268	ip_summed:2,
6869c4d8 HW	269	nohdr:1,
6869c4d8 HW	270	nfctinfo:3;
d179cd12	271	__u8 pkt_type:3,
b84f4cc9 PM	272	fclone:2,
b84f4cc9 PM	273	ipvs_property:1;
a0d3bea3	274	__be16 protocol;
1da177e4 LT	275
1da177e4 LT	276	void (destructor)(struct sk_buff skb);
9fb9cbb1	277	#if defined(CONFIG_NF_CONNTRACK) \|\| defined(CONFIG_NF_CONNTRACK_MODULE)
5f79e0f9	278	struct nf_conntrack *nfct;
9fb9cbb1 YK	279	struct sk_buff *nfct_reasm;
9fb9cbb1 YK	280	#endif
1da177e4 LT	281	#ifdef CONFIG_BRIDGE_NETFILTER
	282	struct nf_bridge_info *nf_bridge;
	283	#endif
1da177e4	284	#ifdef CONFIG_NET_SCHED
b6b99eb5	285	__u16 tc_index; /* traffic control index */
1da177e4	286	#ifdef CONFIG_NET_CLS_ACT
b6b99eb5	287	__u16 tc_verd; /* traffic control verdict */
1da177e4	288	#endif
1da177e4	289	#endif
97fc2f08 CL	290	#ifdef CONFIG_NET_DMA
	291	dma_cookie_t dma_cookie;
	292	#endif
984bc16c JM	293	#ifdef CONFIG_NETWORK_SECMARK
	294	__u32 secmark;
	295	#endif
1da177e4	296
82e91ffe	297	__u32 mark;
1da177e4	298
27a884dc ACM	299	sk_buff_data_t transport_header;
	300	sk_buff_data_t network_header;
	301	sk_buff_data_t mac_header;
1da177e4	302	/* These elements must be at the end, see alloc_skb() for details. */
27a884dc	303	sk_buff_data_t tail;
4305b541	304	sk_buff_data_t end;
1da177e4	305	unsigned char *head,
4305b541	306	*data;
27a884dc ACM	307	unsigned int truesize;
27a884dc ACM	308	atomic_t users;
1da177e4 LT	309	};
	310
	311	#ifdef __KERNEL__
	312	/*
	313	* Handling routines are only of interest to the kernel
	314	*/
	315	#include <linux/slab.h>
	316
	317	#include <asm/system.h>
	318