[PATCH 08/14] nvmet: use nvme write cmd group setting op_flag

[Logan Gunthorpe]

On 2020-08-10 12:54 p.m., Chaitanya Kulkarni wrote:
> The function nvme_is_write() only checks the last bit of the opcode to
> determine if command is a write command or not based on that it sets
> the bio->bi_opf for passthru bio with REQ_SYNC | REQ_IDLE.
> 
> The condition is true for nvme_cmd_write (opcode 0x01), but there are
> commands present in the NVMe command set and are part for NVM Write
> Command Group that doesn't have a last bit set. e.g.
> nvme_cmd_write_zeroes 0x08. With current implementation for these
> commands we will never set the REQ_SYNC for bio->bi_opf even though
> command is from NVMe write command set.
> 
> For passthru backend introduce nvmet_write_cmd_group() and use the
> commands from NVMe 1.4 spec write command group to set the REQ_SYNC
> flag for passthru bio and update nvmet_passthru_map_sg accordingly.
> Since these are low frequency commands annotate condition with
> unlikely respectively.
> 
> Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni at wdc.com>
> ---
>  drivers/nvme/target/passthru.c | 31 ++++++++++++++++++++++++++++---
>  1 file changed, 28 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/nvme/target/passthru.c b/drivers/nvme/target/passthru.c
> index 0b18038c44bb..5f06f4290c52 100644
> --- a/drivers/nvme/target/passthru.c
> +++ b/drivers/nvme/target/passthru.c
> @@ -176,6 +176,29 @@ static void nvmet_passthru_execute_cmd_work(struct work_struct *w)
>  	nvmet_passthru_req_done(rq, 0 /* this value is not used for request */);
>  }
>  
> +static inline bool nvmet_write_cmd_group(__u8 opcode)
> +{
> +	bool ret;
> +
> +	/* NVM Express Revision 1.4 Figure 462. */
> +	switch (opcode) {
> +	case nvme_admin_format_nvm:
> +	case nvme_admin_ns_attach:
> +	case nvme_admin_ns_mgmt:
> +	case nvme_admin_sanitize_nvm:
> +	case nvme_admin_security_send:

All of these admin commands are rejected as INVALID_OPCODE in
nvmet_parse_passthru_admin_cmd(). So adding them here seems confusing at
best.

Logan