From 801625e69d947b0f9291d77bb1deb7545525c66d Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Fri, 11 Dec 2020 21:39:24 +0300 Subject: [PATCH] block/throttle-groups: throttle_group_co_io_limits_intercept(): 64bit bytes 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 Reviewed-by: Eric Blake Reviewed-by: Alberto Garcia Message-Id: <20201211183934.169161-7-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake --- block/throttle-groups.c | 5 ++++- include/block/throttle-groups.h | 2 +- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/block/throttle-groups.c b/block/throttle-groups.c index abd16ed9db..fb203c3ced 100644 --- a/block/throttle-groups.c +++ b/block/throttle-groups.c @@ -358,12 +358,15 @@ static void schedule_next_request(ThrottleGroupMember *tgm, bool is_write) * @is_write: the type of operation (read/write) */ void coroutine_fn throttle_group_co_io_limits_intercept(ThrottleGroupMember *tgm, - unsigned int bytes, + int64_t bytes, bool is_write) { bool must_wait; ThrottleGroupMember *token; ThrottleGroup *tg = container_of(tgm->throttle_state, ThrottleGroup, ts); + + assert(bytes >= 0); + qemu_mutex_lock(&tg->lock); /* First we check if this I/O has to be throttled. */ diff --git a/include/block/throttle-groups.h b/include/block/throttle-groups.h index 8bf7d233fa..9541b32432 100644 --- a/include/block/throttle-groups.h +++ b/include/block/throttle-groups.h @@ -77,7 +77,7 @@ void throttle_group_unregister_tgm(ThrottleGroupMember *tgm); void throttle_group_restart_tgm(ThrottleGroupMember *tgm); void coroutine_fn throttle_group_co_io_limits_intercept(ThrottleGroupMember *tgm, - unsigned int bytes, + int64_t bytes, bool is_write); void throttle_group_attach_aio_context(ThrottleGroupMember *tgm, AioContext *new_context);