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>
801625e69d