Re: [PATCH 10/15] block/nvme: Use definitions instead of magic values in add_io_queue()

[Philippe Mathieu-Daudé]

On 10/14/20 5:58 PM, Philippe Mathieu-Daudé wrote:
> Replace magic values by definitions, and simplifiy since the
> number of queues will never reach 64K.
>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>   block/nvme.c | 9 +++++----
>   1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/block/nvme.c b/block/nvme.c
> index b841c5950c5..11fba2d754d 100644
> --- a/block/nvme.c
> +++ b/block/nvme.c
> @@ -652,6 +652,7 @@ static bool nvme_add_io_queue(BlockDriverState *bs,
>       NvmeCmd cmd;
>       unsigned queue_size = NVME_QUEUE_SIZE;
>   
> +    assert(n <= UINT16_MAX);
>       q = nvme_create_queue_pair(s, aio_context, n, queue_size, errp);
>       if (!q) {
>           return false;
> @@ -659,8 +660,8 @@ static bool nvme_add_io_queue(BlockDriverState *bs,
>       cmd = (NvmeCmd) {
>           .opcode = NVME_ADM_CMD_CREATE_CQ,
>           .dptr.prp1 = cpu_to_le64(q->cq.iova),
> -        .cdw10 = cpu_to_le32(((queue_size - 1) << 16) | (n & 0xFFFF)),
> -        .cdw11 = cpu_to_le32(0x3),
> +        .cdw10 = cpu_to_le32(((queue_size - 1) << 16) | n),

We can use NVME_NUM_REQS here and drop the queue_size variable.

> +        .cdw11 = cpu_to_le32(NVME_CQ_IEN | NVME_CQ_PC),
>       };
>       if (nvme_cmd_sync(bs, s->queues[INDEX_ADMIN], &cmd)) {
>           error_setg(errp, "Failed to create CQ io queue [%u]", n);
> @@ -669,8 +670,8 @@ static bool nvme_add_io_queue(BlockDriverState *bs,
>       cmd = (NvmeCmd) {
>           .opcode = NVME_ADM_CMD_CREATE_SQ,
>           .dptr.prp1 = cpu_to_le64(q->sq.iova),
> -        .cdw10 = cpu_to_le32(((queue_size - 1) << 16) | (n & 0xFFFF)),
> -        .cdw11 = cpu_to_le32(0x1 | (n << 16)),
> +        .cdw10 = cpu_to_le32(((queue_size - 1) << 16) | n),
> +        .cdw11 = cpu_to_le32(NVME_SQ_PC | (n << 16)),
>       };
>       if (nvme_cmd_sync(bs, s->queues[INDEX_ADMIN], &cmd)) {
>           error_setg(errp, "Failed to create SQ io queue [%u]", n);