On Fri, Sep 11, 2020 at 05:53:36PM -0400, Mike Snitzer wrote:
> blk_queue_get_max_sectors() has been trained for REQ_OP_WRITE_SAME and
> REQ_OP_WRITE_ZEROES yet blk_rq_get_max_sectors() didn't call it for
> those operations.
Actually WRITE_SAME & WRITE_ZEROS are handled by the following if
chunk_sectors is set:
return min(blk_max_size_offset(q, offset),
blk_queue_get_max_sectors(q, req_op(rq)));
> Also, there is no need to avoid blk_max_size_offset() if
> 'chunk_sectors' isn't set because it falls back to 'max_sectors'.
>
> Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
> ---
> include/linux/blkdev.h | 19 +++++++++++++------
> 1 file changed, 13 insertions(+), 6 deletions(-)
>
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index bb5636cc17b9..453a3d735d66 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -1070,17 +1070,24 @@ static inline unsigned int blk_rq_get_max_sectors(struct request *rq,
> sector_t offset)
> {
> struct request_queue *q = rq->q;
> + int op;
> + unsigned int max_sectors;
>
> if (blk_rq_is_passthrough(rq))
> return q->limits.max_hw_sectors;
>
> - if (!q->limits.chunk_sectors ||
> - req_op(rq) == REQ_OP_DISCARD ||
> - req_op(rq) == REQ_OP_SECURE_ERASE)
> - return blk_queue_get_max_sectors(q, req_op(rq));
> + op = req_op(rq);
> + max_sectors = blk_queue_get_max_sectors(q, op);
>
> - return min(blk_max_size_offset(q, offset),
> - blk_queue_get_max_sectors(q, req_op(rq)));
> + switch (op) {
> + case REQ_OP_DISCARD:
> + case REQ_OP_SECURE_ERASE:
> + case REQ_OP_WRITE_SAME:
> + case REQ_OP_WRITE_ZEROES:
> + return max_sectors;
> + }
> +
> + return min(blk_max_size_offset(q, offset), max_sectors);
> }
It depends if offset & chunk_sectors limit for WRITE_SAME & WRITE_ZEROS
needs to be considered.
Thanks,
Ming
