diff options
| author | Eric Blake <eblake@redhat.com> | 2016-06-23 16:37:20 -0600 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2016-07-05 16:46:25 +0200 |
| commit | 29cc6a6834add5cddbc391d07c1b3ace2ad9b8eb (patch) | |
| tree | bed8a78c9b19f3199fdc21938b4e723a7ab7c089 /include | |
| parent | 5def6b80e1eca696c1fc6099e7f4d36729686402 (diff) | |
block: Wording tweaks to write zeroes limits
Improve the documentation of the write zeroes limits, to mention
additional constraints that drivers should observe. Worth squashing
into commit cf081fca, if that hadn't been pushed already :)
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 | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/include/block/block_int.h b/include/block/block_int.h index 7d2b152779..7a4a00fdfc 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -331,11 +331,14 @@ typedef struct BlockLimits { int64_t discard_alignment; /* maximum number of bytes that can zeroized at once (since it is - * signed, it must be < 2G, if set) */ + * signed, it must be < 2G, if set), should be multiple of + * pwrite_zeroes_alignment. May be 0 if no inherent 32-bit limit */ int32_t max_pwrite_zeroes; /* optimal alignment for write zeroes requests in bytes, must be - * power of 2, and less than max_pwrite_zeroes if that is set */ + * power of 2, less than max_pwrite_zeroes if that is set, and + * multiple of bs->request_alignment. May be 0 if + * bs->request_alignment is good enough */ uint32_t pwrite_zeroes_alignment; /* optimal transfer length in bytes (must be power of 2, and |