Commit 29cc6a68 authored by Eric Blake's avatar Eric Blake Committed by Kevin Wolf
Browse files

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: default avatarEric Blake <eblake@redhat.com>
Reviewed-by: default avatarFam Zheng <famz@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 5def6b80

include/block/block_int.h

+5 −2
Original line number Diff line number Diff line
@@ -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