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Re: [PATCH v4 13/16] block/io: support int64_t bytes in bdrv_aligned_pre
Re: [PATCH v4 13/16] block/io: support int64_t bytes in bdrv_aligned_preadv()
Sat, 23 Jan 2021 17:34:35 +0300
Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.1
22.01.2021 19:54, Eric Blake wrote:
On 12/11/20 12:39 PM, Vladimir Sementsov-Ogievskiy wrote:
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
So, prepare bdrv_aligned_preadv() now.
Make byte variable in bdrv_padding_rmw_read() int64_t, as it defined
only to be passed to bdrv_aligned_preadv().
Reads awkwardly, how about:
Make the byte variable in bdrv_padding_rmw_read() int64_t, as it is only
used for pass-through to bdrv_aligned_preadv().
and also s/byte/bytes/
All bdrv_aligned_preadv() callers are safe as type is widening. Let's
- add a new-style assertion that request is good.
- callees bdrv_is_allocated(), bdrv_co_do_copy_on_readv() supports
- conversion of bytes_remaining is OK, as we never has requests
- looping through bytes_remaining is ok, num is updated to int64_t
- for bdrv_driver_preadv we have same limit of max_transfer
- qemu_iovec_memset is OK, as bytes+qiov_offset should not overflow
qiov->size anyway (thanks to bdrv_check_qiov_request())
Signed-off-by: Vladimir Sementsov-Ogievskiy <firstname.lastname@example.org>
block/io.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
Reviewed-by: Eric Blake <email@example.com>