From fed33bd175f663cc8c13f8a490a4f35a19756cfe Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Fri, 11 Oct 2019 12:07:07 +0300 Subject: hbitmap: handle set/reset with zero length Passing zero length to these functions leads to unpredicted results. Zero-length set/reset may occur in active-mirror, on zero-length write (which is unlikely, but not guaranteed to never happen). Let's just do nothing on zero-length request. Signed-off-by: Vladimir Sementsov-Ogievskiy Message-id: 20191011090711.19940-2-vsementsov@virtuozzo.com Reviewed-by: Max Reitz Cc: qemu-stable@nongnu.org Signed-off-by: Max Reitz --- util/hbitmap.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'util') diff --git a/util/hbitmap.c b/util/hbitmap.c index 66db87c..242c6e5 100644 --- a/util/hbitmap.c +++ b/util/hbitmap.c @@ -387,6 +387,10 @@ void hbitmap_set(HBitmap *hb, uint64_t start, uint64_t count) uint64_t first, n; uint64_t last = start + count - 1; + if (count == 0) { + return; + } + trace_hbitmap_set(hb, start, count, start >> hb->granularity, last >> hb->granularity); @@ -478,6 +482,10 @@ void hbitmap_reset(HBitmap *hb, uint64_t start, uint64_t count) uint64_t last = start + count - 1; uint64_t gran = 1ULL << hb->granularity; + if (count == 0) { + return; + } + assert(QEMU_IS_ALIGNED(start, gran)); assert(QEMU_IS_ALIGNED(count, gran) || (start + count == hb->orig_size)); -- cgit v1.1 From f16ba00de946517e5cca4edeeec3e21f8f77132d Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Tue, 22 Oct 2019 14:18:03 +0300 Subject: util: introduce SharedResource Introduce an API for some shared splittable resource, like memory. It's going to be used by backup. Backup uses both read/write io and copy_range. copy_range may consume memory implictly, so the new API is abstract: it doesn't allocate any real memory but only hands out tickets. The idea is that we have some total amount of something and callers should wait in coroutine queue if there is not enough of the resource at the moment. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Max Reitz Message-id: 20191022111805.3432-5-vsementsov@virtuozzo.com Signed-off-by: Max Reitz --- util/Makefile.objs | 1 + util/qemu-co-shared-resource.c | 76 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 77 insertions(+) create mode 100644 util/qemu-co-shared-resource.c (limited to 'util') diff --git a/util/Makefile.objs b/util/Makefile.objs index 41bf59d..df124af 100644 --- a/util/Makefile.objs +++ b/util/Makefile.objs @@ -37,6 +37,7 @@ util-obj-y += rcu.o util-obj-$(CONFIG_MEMBARRIER) += sys_membarrier.o util-obj-y += qemu-coroutine.o qemu-coroutine-lock.o qemu-coroutine-io.o util-obj-y += qemu-coroutine-sleep.o +util-obj-y += qemu-co-shared-resource.o util-obj-y += coroutine-$(CONFIG_COROUTINE_BACKEND).o util-obj-y += buffer.o util-obj-y += timed-average.o diff --git a/util/qemu-co-shared-resource.c b/util/qemu-co-shared-resource.c new file mode 100644 index 0000000..1c83cd9 --- /dev/null +++ b/util/qemu-co-shared-resource.c @@ -0,0 +1,76 @@ +/* + * 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. + */ + +#include "qemu/osdep.h" +#include "qemu/coroutine.h" +#include "qemu/co-shared-resource.h" + +struct SharedResource { + uint64_t total; + uint64_t available; + + CoQueue queue; +}; + +SharedResource *shres_create(uint64_t total) +{ + SharedResource *s = g_new0(SharedResource, 1); + + s->total = s->available = total; + qemu_co_queue_init(&s->queue); + + return s; +} + +void shres_destroy(SharedResource *s) +{ + assert(s->available == s->total); + g_free(s); +} + +bool co_try_get_from_shres(SharedResource *s, uint64_t n) +{ + if (s->available >= n) { + s->available -= n; + return true; + } + + return false; +} + +void coroutine_fn co_get_from_shres(SharedResource *s, uint64_t n) +{ + assert(n <= s->total); + while (!co_try_get_from_shres(s, n)) { + qemu_co_queue_wait(&s->queue, NULL); + } +} + +void coroutine_fn co_put_to_shres(SharedResource *s, uint64_t n) +{ + assert(s->total - s->available >= n); + s->available += n; + qemu_co_queue_restart_all(&s->queue); +} -- cgit v1.1