[PATCH 12/16] nvme-auth: convert dhchap_auth_list to an array

[Hannes Reinecke]

On 11/9/22 04:44, Sagi Grimberg wrote:
> We know exactly how many dhchap contexts we will need, there is no need
> to hold a list that we need to protect with a mutex. Convert to
> a dynamically allocated array. And dhchap_context access state is
> maintained by the chap itself.
> 
> Make dhchap_auth_mutex protect only the ctrl host_key and ctrl_key
> in a fine-graned lock such that there is no long lasting acuisition
> of the lock.
> 
> Signed-off-by: Sagi Grimberg <sagi at grimberg.me>
> ---
>   drivers/nvme/host/auth.c | 113 +++++++++++++++++++++------------------
>   drivers/nvme/host/core.c |   4 ++
>   drivers/nvme/host/nvme.h |   2 +-
>   3 files changed, 65 insertions(+), 54 deletions(-)
> 
> diff --git a/drivers/nvme/host/auth.c b/drivers/nvme/host/auth.c
> index 23d486284da9..b78e0df54f6c 100644
> --- a/drivers/nvme/host/auth.c
> +++ b/drivers/nvme/host/auth.c
> @@ -46,6 +46,14 @@ struct nvme_dhchap_queue_context {
>   	(qid == 0) ? 0 : BLK_MQ_REQ_NOWAIT | BLK_MQ_REQ_RESERVED
>   #define nvme_auth_queue_from_qid(ctrl, qid) \
>   	(qid == 0) ? (ctrl)->fabrics_q : (ctrl)->connect_q
> +#define nvme_auth_chap_from_qid(ctrl, qid) \
> +	&((struct nvme_dhchap_queue_context*)(ctrl)->dhchap_ctxs)[qid]
> +#define ctrl_max_dhchaps(ctrl) \
> +	(ctrl)->opts->nr_io_queues + (ctrl)->opts->nr_write_queues + \
> +			(ctrl)->opts->nr_poll_queues + 1
> +#define nvme_foreach_dhchap(i, chap, ctrl) \
> +	for (i = 0, chap = (ctrl)->dhchap_ctxs; \
> +	     i < ctrl_max_dhchaps(ctrl) && chap != NULL; i++, chap++)
>   
>   static int nvme_auth_submit(struct nvme_ctrl *ctrl, int qid,
>   			    void *data, size_t data_len, bool auth_send)

Please use an xarray (cf my patch doing the same).
That leads to far better readable code, and avoid having to do weird casts.

Also, the claim 'we know exactly how many queues' isn't quite true, as 
we only know the _maximum_ number of queues. The controller can (and 
will) decrease this number based on the target configuration.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
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