Re: [PATCH] nvmet-fc: simplify nvmet_fc_alloc_hostport

[Himanshu Madhani <himanshu.madhani@oracle.com>]

> On Mar 16, 2021, at 1:43 AM, amit.engel@dell.com wrote:
> 
> From: Amit Engel <amit.engel@dell.com>
> 
> Once a host is already created,
> avoid allocate additional hostports that will be thrown away.
> add an helper function to handle host search.
> 
> Signed-off-by: Amit Engel <amit.engel@dell.com>
> Signed-off-by: James Smart <jsmart2021@gmail.com>
> ---
> drivers/nvme/target/fc.c | 76 ++++++++++++++++++++++++----------------
> 1 file changed, 45 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/nvme/target/fc.c b/drivers/nvme/target/fc.c
> index d375745fc4ed..4762f298e579 100644
> --- a/drivers/nvme/target/fc.c
> +++ b/drivers/nvme/target/fc.c
> @@ -1020,61 +1020,75 @@ nvmet_fc_free_hostport(struct nvmet_fc_hostport *hostport)
> 	nvmet_fc_hostport_put(hostport);
> }
> 
> +static struct nvmet_fc_hostport *
> +nvmet_fc_match_hostport(struct nvmet_fc_tgtport *tgtport, void *hosthandle)
> +{
> +	struct nvmet_fc_hostport *host;
> +
> +	/* tgtport->lock is held by caller */
> +
> +	list_for_each_entry(host, &tgtport->host_list, host_list) {
> +		if (host->hosthandle == hosthandle && !host->invalid) {
> +			if (nvmet_fc_hostport_get(host))
> +				return (host);
> +		}
> +	}
> +
> +	return (NULL);
> +}
> +
> static struct nvmet_fc_hostport *
> nvmet_fc_alloc_hostport(struct nvmet_fc_tgtport *tgtport, void *hosthandle)
> {
> -	struct nvmet_fc_hostport *newhost, *host, *match = NULL;
> +	struct nvmet_fc_hostport *newhost, *match = NULL;
> 	unsigned long flags;
> 
> 	/* if LLDD not implemented, leave as NULL */
> 	if (!hosthandle)
> 		return NULL;
> 
> -	/* take reference for what will be the newly allocated hostport */
> +	/* take reference for what will be the newly allocated hostport if
> +	 * we end up using a new allocation
> +	 */

Small nit.. Please fix the comment formatting for multi-line 

> 	if (!nvmet_fc_tgtport_get(tgtport))
> 		return ERR_PTR(-EINVAL);
> 
> +	spin_lock_irqsave(&tgtport->lock, flags);
> +	match = nvmet_fc_match_hostport(tgtport, hosthandle);
> +	spin_unlock_irqrestore(&tgtport->lock, flags);
> +
> +	if (match) {
> +		/* no new allocation - release reference */
> +		nvmet_fc_tgtport_put(tgtport);
> +		return match;
> +	}
> +
> 	newhost = kzalloc(sizeof(*newhost), GFP_KERNEL);
> 	if (!newhost) {
> -		spin_lock_irqsave(&tgtport->lock, flags);
> -		list_for_each_entry(host, &tgtport->host_list, host_list) {
> -			if (host->hosthandle == hosthandle && !host->invalid) {
> -				if (nvmet_fc_hostport_get(host)) {
> -					match = host;
> -					break;
> -				}
> -			}
> -		}
> -		spin_unlock_irqrestore(&tgtport->lock, flags);
> -		/* no allocation - release reference */
> +		/* no new allocation - release reference */
> 		nvmet_fc_tgtport_put(tgtport);
> -		return (match) ? match : ERR_PTR(-ENOMEM);
> +		return ERR_PTR(-ENOMEM);
> 	}
> 
> -	newhost->tgtport = tgtport;
> -	newhost->hosthandle = hosthandle;
> -	INIT_LIST_HEAD(&newhost->host_list);
> -	kref_init(&newhost->ref);
> -
> 	spin_lock_irqsave(&tgtport->lock, flags);
> -	list_for_each_entry(host, &tgtport->host_list, host_list) {
> -		if (host->hosthandle == hosthandle && !host->invalid) {
> -			if (nvmet_fc_hostport_get(host)) {
> -				match = host;
> -				break;
> -			}
> -		}
> -	}
> +	match = nvmet_fc_match_hostport(tgtport, hosthandle);
> 	if (match) {
> +		/* new allocation not needed */
> 		kfree(newhost);
> -		newhost = NULL;
> -		/* releasing allocation - release reference */
> +		newhost = match;
> +		/* no new allocation - release reference */
> 		nvmet_fc_tgtport_put(tgtport);
> -	} else
> +	} else {
> +		newhost->tgtport = tgtport;
> +		newhost->hosthandle = hosthandle;
> +		INIT_LIST_HEAD(&newhost->host_list);
> +		kref_init(&newhost->ref);
> +
> 		list_add_tail(&newhost->host_list, &tgtport->host_list);
> +	}
> 	spin_unlock_irqrestore(&tgtport->lock, flags);
> 
> -	return (match) ? match : newhost;
> +	return newhost;
> }
> 
> static void
> -- 
> 2.18.2
> 
> 
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code looks good.

Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>

--
Himanshu Madhani	 Oracle Linux Engineering


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