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| author | Eric Blake <eblake@redhat.com> | 2016-06-23 16:37:19 -0600 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2016-07-05 16:46:25 +0200 |
| commit | 5def6b80e1eca696c1fc6099e7f4d36729686402 (patch) | |
| tree | 5948b16242a3b57bb1dffa6c650ef05e9154f59e /include | |
| parent | 79ba8c986adb9ca07f52abd0b3d33c3aee8e6ff9 (diff) | |
| download | qemu-5def6b80e1eca696c1fc6099e7f4d36729686402.zip qemu-5def6b80e1eca696c1fc6099e7f4d36729686402.tar.gz qemu-5def6b80e1eca696c1fc6099e7f4d36729686402.tar.bz2 | |
block: Switch transfer length bounds to byte-based
Sector-based limits are awkward to think about; in our on-going
quest to move to byte-based interfaces, convert max_transfer_length
and opt_transfer_length. Rename them (dropping the _length suffix)
so that the compiler will help us catch the change in semantics
across any rebased code, and improve the documentation. Use unsigned
values, so that we don't have to worry about negative values and
so that bit-twiddling is easier; however, we are still constrained
by 2^31 of signed int in most APIs.
When a value comes from an external source (iscsi and raw-posix),
sanitize the results to ensure that opt_transfer is a power of 2.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/block/block_int.h | 13 | ||||
| -rw-r--r-- | include/sysemu/block-backend.h | 2 |
2 files changed, 9 insertions, 6 deletions
diff --git a/include/block/block_int.h b/include/block/block_int.h index 2057156..7d2b152 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -338,11 +338,14 @@ typedef struct BlockLimits { * power of 2, and less than max_pwrite_zeroes if that is set */ uint32_t pwrite_zeroes_alignment; - /* optimal transfer length in sectors */ - int opt_transfer_length; - - /* maximal transfer length in sectors */ - int max_transfer_length; + /* optimal transfer length in bytes (must be power of 2, and + * multiple of bs->request_alignment), or 0 if no preferred size */ + uint32_t opt_transfer; + + /* maximal transfer length in bytes (need not be power of 2, but + * should be multiple of opt_transfer), or 0 for no 32-bit limit. + * For now, anything larger than INT_MAX is clamped down. */ + uint32_t max_transfer; /* memory alignment so that no bounce buffer is needed */ size_t min_mem_alignment; diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h index c04af8e..2469a1c 100644 --- a/include/sysemu/block-backend.h +++ b/include/sysemu/block-backend.h @@ -170,7 +170,7 @@ bool blk_is_available(BlockBackend *blk); void blk_lock_medium(BlockBackend *blk, bool locked); void blk_eject(BlockBackend *blk, bool eject_flag); int blk_get_flags(BlockBackend *blk); -int blk_get_max_transfer_length(BlockBackend *blk); +uint32_t blk_get_max_transfer(BlockBackend *blk); int blk_get_max_iov(BlockBackend *blk); void blk_set_guest_block_size(BlockBackend *blk, int align); void *blk_try_blockalign(BlockBackend *blk, size_t size); |