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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
/*
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* Helper functionality for distributing a fixed total amount of
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* an abstract resource among multiple coroutines.
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*
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* Copyright (c) 2019 Virtuozzo International GmbH
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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 deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* 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
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* THE 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 FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#ifndef QEMU_CO_SHARED_RESOURCE_H
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#define QEMU_CO_SHARED_RESOURCE_H
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/* Accesses to co-shared-resource API are thread-safe */
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typedef struct SharedResource SharedResource;
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/*
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* Create SharedResource structure
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*
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* @total: total amount of some resource to be shared between clients
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*/
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SharedResource *shres_create(uint64_t total);
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/*
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* Release SharedResource structure
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*
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* This function may only be called once everything allocated by all
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* clients has been deallocated.
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*/
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void shres_destroy(SharedResource *s);
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/*
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* Try to allocate an amount of @n. Return true on success, and false
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* if there is too little left of the collective resource to fulfill
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* the request.
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*/
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bool co_try_get_from_shres(SharedResource *s, uint64_t n);
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/*
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* Allocate an amount of @n, and, if necessary, yield until
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* that becomes possible.
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*/
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void coroutine_fn co_get_from_shres(SharedResource *s, uint64_t n);
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/*
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* Deallocate an amount of @n. The total amount allocated by a caller
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* does not need to be deallocated/released with a single call, but may
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* be split over several calls. For example, get(4), get(3), and then
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* put(5), put(2).
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*/
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void coroutine_fn co_put_to_shres(SharedResource *s, uint64_t n);
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#endif /* QEMU_CO_SHARED_RESOURCE_H */
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