Re: [PATCH 10/17] scsi_dh_alua: Use separate alua_port_group structure

Hannes Reinecke
2015-05-07T13:37:48Z

On 05/07/2015 02:34 PM, Bart Van Assche wrote:
> On 05/04/15 14:42, Hannes Reinecke wrote:
>> +static void release_port_group(struct kref *kref)
>> +{
>> + struct alua_port_group *pg;
>> +
>> + pg = container_of(kref, struct alua_port_group, kref);
>> + printk(KERN_WARNING "alua: release port group %d\n",
>> pg->group_id);
>
> Does this really need to be a warning ?
>
No, you are right. This it mainly for debugging.

>> + spin_lock(&port_group_lock);
>> + pg = kzalloc(sizeof(struct alua_port_group), GFP_ATOMIC);
>> + if (!pg) {
>> + sdev_printk(KERN_WARNING, sdev,
>> + "%s: kzalloc port group failed\n",
>> + ALUA_DH_NAME);
>> + /* Temporary failure, bypass */
>> + spin_unlock(&port_group_lock);
>> + return SCSI_DH_DEV_TEMP_BUSY;
>> + }
>> + pg->group_id = group_id;
>> + pg->buff = pg->inq;
>> + pg->bufflen = ALUA_INQUIRY_SIZE;
>> + pg->tpgs = h->tpgs;
>> + pg->state = TPGS_STATE_OPTIMIZED;
>> + kref_init(&pg->kref);
>> + list_add(&pg->node, &port_group_list);
>> + h->pg = pg;
>> + spin_unlock(&port_group_lock);
>
> Sorry but it's not clear to me why the kzalloc() statement happens
> under port_group_lock. Please consider to perform only the
> list_add() statement under port_group_lock, to perform all other
> assignments without holding that lock and to change GFP_ATOMIC into
> GFP_KERNEL.
>
Right, kzalloc() doesn't need to happen under the lock.

>> - len = (h->buff[0] << 24) + (h->buff[1] << 16) +
>> - (h->buff[2] << 8) + h->buff[3] + 4;
>> + len = (pg->buff[0] << 24) + (pg->buff[1] << 16) +
>> + (pg->buff[2] << 8) + pg->buff[3] + 4;
>
> Has it been considered to use get_unaligned_be32() instead ?
>
Okay, will do.

Cheers,

Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@suse.de +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
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