On 2020/05/22 22:25, Coly Li wrote:
> Currently REQ_OP_ZONE_RESET and REQ_OP_ZONE_RESET_ALL are defined as
> even numbers 6 and 8, such zone reset bios are treated as READ bios by
> bio_data_dir(), which is obviously misleading.
>
> The macro bio_data_dir() is defined in include/linux/bio.h as,
> 55 #define bio_data_dir(bio) \
> 56 (op_is_write(bio_op(bio)) ? WRITE : READ)
>
> And op_is_write() is defined in include/linux/blk_types.h as,
> 397 static inline bool op_is_write(unsigned int op)
> 398 {
> 399 return (op & 1);
> 400 }
>
> The convention of op_is_write() is when there is data transfer then the
> op code should be odd number, and treat as a write op. bio_data_dir()
> treats all bio direction as READ if op_is_write() reports false, and
> WRITE if op_is_write() reports true.
>
> Because REQ_OP_ZONE_RESET and REQ_OP_ZONE_RESET_ALL are even numbers,
> although they don't transfer data but reporting them as READ bio by
> bio_data_dir() is misleading and might be wrong. Because these two
> commands will reset the writer pointers of the resetting zones, and all
> content after the reset write pointer will be invalid and unaccessible,
> obviously they are not READ bios in any means.
>
> This patch changes REQ_OP_ZONE_RESET from 6 to 15, and changes
> REQ_OP_ZONE_RESET_ALL from 8 to 17. Now bios with these two op code
> can be treated as WRITE by bio_data_dir(). Although they don't transfer
> data, now we keep them consistent with REQ_OP_DISCARD and
> REQ_OP_WRITE_ZEROES with the ituition that they change on-media content
> and should be WRITE request.
>
> Signed-off-by: Coly Li <colyli@xxxxxxx>
> Cc: Chaitanya Kulkarni <Chaitanya.Kulkarni@xxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Damien Le Moal <Damien.LeMoal@xxxxxxx>
> Cc: Hannes Reinecke <hare@xxxxxxx>
> Cc: Jens Axboe <axboe@xxxxxx>
> Cc: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
> Cc: Keith Busch <kbusch@xxxxxxxxxx>
> Cc: Shaun Tancheff <shaun.tancheff@xxxxxxxxxxx>
> ---
> include/linux/blk_types.h | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
> index ccb895f911b1..447b46a0accf 100644
> --- a/include/linux/blk_types.h
> +++ b/include/linux/blk_types.h
> @@ -300,12 +300,8 @@ enum req_opf {
> REQ_OP_DISCARD = 3,
> /* securely erase sectors */
> REQ_OP_SECURE_ERASE = 5,
> - /* reset a zone write pointer */
> - REQ_OP_ZONE_RESET = 6,
> /* write the same sector many times */
> REQ_OP_WRITE_SAME = 7,
> - /* reset all the zone present on the device */
> - REQ_OP_ZONE_RESET_ALL = 8,
> /* write the zero filled sector many times */
> REQ_OP_WRITE_ZEROES = 9,
> /* Open a zone */
> @@ -316,6 +312,10 @@ enum req_opf {
> REQ_OP_ZONE_FINISH = 12,
> /* write data at the current zone write pointer */
> REQ_OP_ZONE_APPEND = 13,
> + /* reset a zone write pointer */
> + REQ_OP_ZONE_RESET = 15,
> + /* reset all the zone present on the device */
> + REQ_OP_ZONE_RESET_ALL = 17,
>
> /* SCSI passthrough using struct scsi_request */
> REQ_OP_SCSI_IN = 32,
>
I think this is OK. Not sure if it needs to be a separate patch or if it should
be part of the bcache series... Jens ?
Reviewed-by: Damien Le Moal <damien.lemoal@xxxxxxx>
--
Damien Le Moal
Western Digital Research
