55fa54a789
co-shared-resource is currently not thread-safe, as also reported in co-shared-resource.h. Add a QemuMutex because co_try_get_from_shres can also be invoked from non-coroutine context. Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Message-Id: <20210614081130.22134-6-eesposit@redhat.com> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
70 lines
2.4 KiB
C
70 lines
2.4 KiB
C
/*
|
|
* Helper functionality for distributing a fixed total amount of
|
|
* an abstract resource among multiple coroutines.
|
|
*
|
|
* Copyright (c) 2019 Virtuozzo International GmbH
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
* of this software and associated documentation files (the "Software"), to deal
|
|
* in the Software without restriction, including without limitation the rights
|
|
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
* copies of the Software, and to permit persons to whom the Software is
|
|
* furnished to do so, subject to the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice shall be included in
|
|
* all copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
|
|
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
|
* THE SOFTWARE.
|
|
*/
|
|
|
|
#ifndef QEMU_CO_SHARED_RESOURCE_H
|
|
#define QEMU_CO_SHARED_RESOURCE_H
|
|
|
|
/* Accesses to co-shared-resource API are thread-safe */
|
|
typedef struct SharedResource SharedResource;
|
|
|
|
/*
|
|
* Create SharedResource structure
|
|
*
|
|
* @total: total amount of some resource to be shared between clients
|
|
*/
|
|
SharedResource *shres_create(uint64_t total);
|
|
|
|
/*
|
|
* Release SharedResource structure
|
|
*
|
|
* This function may only be called once everything allocated by all
|
|
* clients has been deallocated.
|
|
*/
|
|
void shres_destroy(SharedResource *s);
|
|
|
|
/*
|
|
* Try to allocate an amount of @n. Return true on success, and false
|
|
* if there is too little left of the collective resource to fulfill
|
|
* the request.
|
|
*/
|
|
bool co_try_get_from_shres(SharedResource *s, uint64_t n);
|
|
|
|
/*
|
|
* Allocate an amount of @n, and, if necessary, yield until
|
|
* that becomes possible.
|
|
*/
|
|
void coroutine_fn co_get_from_shres(SharedResource *s, uint64_t n);
|
|
|
|
/*
|
|
* Deallocate an amount of @n. The total amount allocated by a caller
|
|
* does not need to be deallocated/released with a single call, but may
|
|
* be split over several calls. For example, get(4), get(3), and then
|
|
* put(5), put(2).
|
|
*/
|
|
void coroutine_fn co_put_to_shres(SharedResource *s, uint64_t n);
|
|
|
|
|
|
#endif /* QEMU_CO_SHARED_RESOURCE_H */
|