Re: [RFC 19/32] crypto/caam_jr: use IO barrier before job ring doorbell

On 29-07-2026 23:24, Stephen Hemminger wrote:
> The barrier orders the input ring descriptor write in DMA memory
> against the MMIO doorbell write. That is device ordering, not SMP
> ordering: rte_io_wmb() is the correct barrier, and on arm64 the
> inner shareable dmb the SMP barrier generated was not sufficient
> to order against the device in the first place.
>
> Signed-off-by: Stephen Hemminger <[email protected]>
Acked-by: Hemant Agrawal <[email protected]>
> ---
>   drivers/crypto/caam_jr/caam_jr.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/crypto/caam_jr/caam_jr.c b/drivers/crypto/caam_jr/caam_jr.c
> index 1f97e72337..7a345c436e 100644
> --- a/drivers/crypto/caam_jr/caam_jr.c
> +++ b/drivers/crypto/caam_jr/caam_jr.c
> @@ -1451,7 +1451,8 @@ caam_jr_enqueue_op(struct rte_crypto_op *op, struct caam_jr_qp *qp)
>   	/* Set ptr in input ring to current descriptor	*/
>   	sec_write_addr(&ring->input_ring[ring->pidx],
>   			(phys_addr_t)caam_jr_vtop_ctx(ctx, ctx->jobdes.desc));
> -	rte_smp_wmb();
> +	/* Descriptor must be visible to the device before the doorbell */
> +	rte_io_wmb();
>   
>   	/* Notify HW that a new job is enqueued */
>   	hw_enqueue_desc_on_job_ring(ring);