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801625e69d
The function is called from 64bit io handlers, and bytes is just passed
to throttle_account() which is 64bit too (unsigned though). So, let's
convert intermediate argument to 64bit too.
This patch is a first in the 64-bit-blocklayer series, so we are
generally moving to int64_t for both offset and bytes parameters on all
io paths. Main motivation is realization of 64-bit write_zeroes
operation for fast zeroing large disk chunks, up to the whole disk.
We chose signed type, to be consistent with off_t (which is signed) and
with possibility for signed return type (where negative value means
error).
Patch-correctness audit by Eric Blake:
Caller has 32-bit, this patch now causes widening which is safe:
block/block-backend.c: blk_do_preadv() passes 'unsigned int'
block/block-backend.c: blk_do_pwritev_part() passes 'unsigned int'
block/throttle.c: throttle_co_pwrite_zeroes() passes 'int'
block/throttle.c: throttle_co_pdiscard() passes 'int'
Caller has 64-bit, this patch fixes potential bug where pre-patch
could narrow, except it's easy enough to trace that callers are still
capped at 2G actions:
block/throttle.c: throttle_co_preadv() passes 'uint64_t'
block/throttle.c: throttle_co_pwritev() passes 'uint64_t'
Implementation in question: block/throttle-groups.c
throttle_group_co_io_limits_intercept() takes 'unsigned int bytes'
and uses it: argument to util/throttle.c throttle_account(uint64_t)
All safe: it patches a latent bug, and does not introduce any 64-bit
gotchas once throttle_co_p{read,write}v are relaxed, and assuming
throttle_account() is not buggy.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-Id: <20201211183934.169161-7-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
92 lines
3.2 KiB
C
92 lines
3.2 KiB
C
/*
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* QEMU block throttling group infrastructure
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*
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* Copyright (C) Nodalink, EURL. 2014
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* Copyright (C) Igalia, S.L. 2015
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*
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* Authors:
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* Benoît Canet <benoit.canet@nodalink.com>
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* Alberto Garcia <berto@igalia.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 or
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* (at your option) version 3 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef THROTTLE_GROUPS_H
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#define THROTTLE_GROUPS_H
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#include "qemu/throttle.h"
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#include "block/block_int.h"
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#include "qom/object.h"
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/* The ThrottleGroupMember structure indicates membership in a ThrottleGroup
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* and holds related data.
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*/
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typedef struct ThrottleGroupMember {
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AioContext *aio_context;
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/* throttled_reqs_lock protects the CoQueues for throttled requests. */
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CoMutex throttled_reqs_lock;
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CoQueue throttled_reqs[2];
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/* Nonzero if the I/O limits are currently being ignored; generally
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* it is zero. Accessed with atomic operations.
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*/
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unsigned int io_limits_disabled;
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/* Number of pending throttle_group_restart_queue_entry() coroutines.
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* Accessed with atomic operations.
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*/
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unsigned int restart_pending;
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/* The following fields are protected by the ThrottleGroup lock.
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* See the ThrottleGroup documentation for details.
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* throttle_state tells us if I/O limits are configured. */
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ThrottleState *throttle_state;
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ThrottleTimers throttle_timers;
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unsigned pending_reqs[2];
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QLIST_ENTRY(ThrottleGroupMember) round_robin;
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} ThrottleGroupMember;
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#define TYPE_THROTTLE_GROUP "throttle-group"
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OBJECT_DECLARE_SIMPLE_TYPE(ThrottleGroup, THROTTLE_GROUP)
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const char *throttle_group_get_name(ThrottleGroupMember *tgm);
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ThrottleState *throttle_group_incref(const char *name);
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void throttle_group_unref(ThrottleState *ts);
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void throttle_group_config(ThrottleGroupMember *tgm, ThrottleConfig *cfg);
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void throttle_group_get_config(ThrottleGroupMember *tgm, ThrottleConfig *cfg);
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void throttle_group_register_tgm(ThrottleGroupMember *tgm,
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const char *groupname,
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AioContext *ctx);
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void throttle_group_unregister_tgm(ThrottleGroupMember *tgm);
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void throttle_group_restart_tgm(ThrottleGroupMember *tgm);
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void coroutine_fn throttle_group_co_io_limits_intercept(ThrottleGroupMember *tgm,
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int64_t bytes,
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bool is_write);
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void throttle_group_attach_aio_context(ThrottleGroupMember *tgm,
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AioContext *new_context);
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void throttle_group_detach_aio_context(ThrottleGroupMember *tgm);
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/*
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* throttle_group_exists() must be called under the global
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* mutex.
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*/
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bool throttle_group_exists(const char *name);
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#endif
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