mirror of https://gitee.com/openkylin/linux.git
xen: sync include/xen/interface/io/ring.h with Xen's newest version
Sync include/xen/interface/io/ring.h with Xen's newest version in order to get the RING_COPY_RESPONSE() and RING_RESPONSE_PROD_OVERFLOW() macros. Note that this will correct the wrong license info by adding the missing original copyright notice. Signed-off-by: Juergen Gross <jgross@suse.com>
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Juergen Gross
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2060061767
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629a5d87e2
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@ -1,15 +1,47 @@
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/* SPDX-License-Identifier: GPL-2.0 */
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/******************************************************************************
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* ring.h
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*
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* Shared producer-consumer ring macros.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to
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* deal in the Software without restriction, including without limitation the
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* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*
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* Tim Deegan and Andrew Warfield November 2004.
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*/
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#ifndef __XEN_PUBLIC_IO_RING_H__
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#define __XEN_PUBLIC_IO_RING_H__
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/*
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* When #include'ing this header, you need to provide the following
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* declaration upfront:
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* - standard integers types (uint8_t, uint16_t, etc)
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* They are provided by stdint.h of the standard headers.
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*
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* In addition, if you intend to use the FLEX macros, you also need to
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* provide the following, before invoking the FLEX macros:
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* - size_t
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* - memcpy
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* - grant_ref_t
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* These declarations are provided by string.h of the standard headers,
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* and grant_table.h from the Xen public headers.
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*/
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#include <xen/interface/grant_table.h>
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typedef unsigned int RING_IDX;
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@ -30,45 +62,42 @@ typedef unsigned int RING_IDX;
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#define __CONST_RING_SIZE(_s, _sz) \
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(__RD32(((_sz) - offsetof(struct _s##_sring, ring)) / \
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sizeof(((struct _s##_sring *)0)->ring[0])))
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/*
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* The same for passing in an actual pointer instead of a name tag.
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*/
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#define __RING_SIZE(_s, _sz) \
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(__RD32(((_sz) - (long)&(_s)->ring + (long)(_s)) / sizeof((_s)->ring[0])))
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(__RD32(((_sz) - (long)(_s)->ring + (long)(_s)) / sizeof((_s)->ring[0])))
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/*
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* Macros to make the correct C datatypes for a new kind of ring.
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*
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* To make a new ring datatype, you need to have two message structures,
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* let's say struct request, and struct response already defined.
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* let's say request_t, and response_t already defined.
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*
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* In a header where you want the ring datatype declared, you then do:
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*
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* DEFINE_RING_TYPES(mytag, struct request, struct response);
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* DEFINE_RING_TYPES(mytag, request_t, response_t);
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*
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* These expand out to give you a set of types, as you can see below.
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* The most important of these are:
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*
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* struct mytag_sring - The shared ring.
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* struct mytag_front_ring - The 'front' half of the ring.
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* struct mytag_back_ring - The 'back' half of the ring.
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* mytag_sring_t - The shared ring.
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* mytag_front_ring_t - The 'front' half of the ring.
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* mytag_back_ring_t - The 'back' half of the ring.
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*
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* To initialize a ring in your code you need to know the location and size
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* of the shared memory area (PAGE_SIZE, for instance). To initialise
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* the front half:
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*
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* struct mytag_front_ring front_ring;
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* SHARED_RING_INIT((struct mytag_sring *)shared_page);
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* FRONT_RING_INIT(&front_ring, (struct mytag_sring *)shared_page,
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* PAGE_SIZE);
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* mytag_front_ring_t front_ring;
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* SHARED_RING_INIT((mytag_sring_t *)shared_page);
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* FRONT_RING_INIT(&front_ring, (mytag_sring_t *)shared_page, PAGE_SIZE);
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*
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* Initializing the back follows similarly (note that only the front
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* initializes the shared ring):
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*
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* struct mytag_back_ring back_ring;
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* BACK_RING_INIT(&back_ring, (struct mytag_sring *)shared_page,
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* PAGE_SIZE);
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* mytag_back_ring_t back_ring;
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* BACK_RING_INIT(&back_ring, (mytag_sring_t *)shared_page, PAGE_SIZE);
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*/
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#define DEFINE_RING_TYPES(__name, __req_t, __rsp_t) \
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@ -83,7 +112,7 @@ union __name##_sring_entry { \
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struct __name##_sring { \
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RING_IDX req_prod, req_event; \
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RING_IDX rsp_prod, rsp_event; \
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uint8_t pad[48]; \
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uint8_t __pad[48]; \
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union __name##_sring_entry ring[1]; /* variable-length */ \
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}; \
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\
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@ -101,8 +130,8 @@ struct __name##_back_ring { \
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RING_IDX req_cons; \
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unsigned int nr_ents; \
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struct __name##_sring *sring; \
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};
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}; \
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\
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/*
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* Macros for manipulating rings.
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*
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@ -122,7 +151,7 @@ struct __name##_back_ring { \
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#define SHARED_RING_INIT(_s) do { \
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(_s)->req_prod = (_s)->rsp_prod = 0; \
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(_s)->req_event = (_s)->rsp_event = 1; \
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memset((_s)->pad, 0, sizeof((_s)->pad)); \
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(void)memset((_s)->__pad, 0, sizeof((_s)->__pad)); \
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} while(0)
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#define FRONT_RING_ATTACH(_r, _s, _i, __size) do { \
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@ -161,34 +190,36 @@ struct __name##_back_ring { \
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#define RING_HAS_UNCONSUMED_RESPONSES(_r) \
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((_r)->sring->rsp_prod - (_r)->rsp_cons)
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#define RING_HAS_UNCONSUMED_REQUESTS(_r) \
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({ \
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#define RING_HAS_UNCONSUMED_REQUESTS(_r) ({ \
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unsigned int req = (_r)->sring->req_prod - (_r)->req_cons; \
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unsigned int rsp = RING_SIZE(_r) - \
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((_r)->req_cons - (_r)->rsp_prod_pvt); \
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req < rsp ? req : rsp; \
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})
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})
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/* Direct access to individual ring elements, by index. */
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#define RING_GET_REQUEST(_r, _idx) \
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(&((_r)->sring->ring[((_idx) & (RING_SIZE(_r) - 1))].req))
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#define RING_GET_RESPONSE(_r, _idx) \
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(&((_r)->sring->ring[((_idx) & (RING_SIZE(_r) - 1))].rsp))
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/*
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* Get a local copy of a request.
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* Get a local copy of a request/response.
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*
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* Use this in preference to RING_GET_REQUEST() so all processing is
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* Use this in preference to RING_GET_{REQUEST,RESPONSE}() so all processing is
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* done on a local copy that cannot be modified by the other end.
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*
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* Note that https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 may cause this
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* to be ineffective where _req is a struct which consists of only bitfields.
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* to be ineffective where dest is a struct which consists of only bitfields.
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*/
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#define RING_COPY_REQUEST(_r, _idx, _req) do { \
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/* Use volatile to force the copy into _req. */ \
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*(_req) = *(volatile typeof(_req))RING_GET_REQUEST(_r, _idx); \
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#define RING_COPY_(type, r, idx, dest) do { \
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/* Use volatile to force the copy into dest. */ \
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*(dest) = *(volatile typeof(dest))RING_GET_##type(r, idx); \
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} while (0)
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#define RING_GET_RESPONSE(_r, _idx) \
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(&((_r)->sring->ring[((_idx) & (RING_SIZE(_r) - 1))].rsp))
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#define RING_COPY_REQUEST(r, idx, req) RING_COPY_(REQUEST, r, idx, req)
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#define RING_COPY_RESPONSE(r, idx, rsp) RING_COPY_(RESPONSE, r, idx, rsp)
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/* Loop termination condition: Would the specified index overflow the ring? */
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#define RING_REQUEST_CONS_OVERFLOW(_r, _cons) \
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@ -198,14 +229,17 @@ struct __name##_back_ring { \
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#define RING_REQUEST_PROD_OVERFLOW(_r, _prod) \
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(((_prod) - (_r)->rsp_prod_pvt) > RING_SIZE(_r))
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/* Ill-behaved backend determination: Can there be this many responses? */
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#define RING_RESPONSE_PROD_OVERFLOW(_r, _prod) \
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(((_prod) - (_r)->rsp_cons) > RING_SIZE(_r))
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#define RING_PUSH_REQUESTS(_r) do { \
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virt_wmb(); /* back sees requests /before/ updated producer index */ \
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virt_wmb(); /* back sees requests /before/ updated producer index */\
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(_r)->sring->req_prod = (_r)->req_prod_pvt; \
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} while (0)
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#define RING_PUSH_RESPONSES(_r) do { \
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virt_wmb(); /* front sees responses /before/ updated producer index */ \
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virt_wmb(); /* front sees resps /before/ updated producer index */ \
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(_r)->sring->rsp_prod = (_r)->rsp_prod_pvt; \
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} while (0)
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@ -242,7 +276,7 @@ struct __name##_back_ring { \
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#define RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(_r, _notify) do { \
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RING_IDX __old = (_r)->sring->req_prod; \
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RING_IDX __new = (_r)->req_prod_pvt; \
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virt_wmb(); /* back sees requests /before/ updated producer index */ \
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virt_wmb(); /* back sees requests /before/ updated producer index */\
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(_r)->sring->req_prod = __new; \
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virt_mb(); /* back sees new requests /before/ we check req_event */ \
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(_notify) = ((RING_IDX)(__new - (_r)->sring->req_event) < \
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@ -252,9 +286,9 @@ struct __name##_back_ring { \
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#define RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(_r, _notify) do { \
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RING_IDX __old = (_r)->sring->rsp_prod; \
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RING_IDX __new = (_r)->rsp_prod_pvt; \
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virt_wmb(); /* front sees responses /before/ updated producer index */ \
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virt_wmb(); /* front sees resps /before/ updated producer index */ \
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(_r)->sring->rsp_prod = __new; \
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virt_mb(); /* front sees new responses /before/ we check rsp_event */ \
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virt_mb(); /* front sees new resps /before/ we check rsp_event */ \
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(_notify) = ((RING_IDX)(__new - (_r)->sring->rsp_event) < \
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(RING_IDX)(__new - __old)); \
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} while (0)
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