Re: [PATCH-v3 00/10] target: se_node_acl + se_lun RCU conversions

From: Hannes Reinecke
Date: Tue May 26 2015 - 09:09:39 EST


On 05/26/2015 08:25 AM, Nicholas A. Bellinger wrote:
> From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
>
> Hi all,
>
> Here is -v3 series for converting LIO target se_node_acl + se_lun
> mapping tables from fixed size arrays to dynamic RCU hlist_heads.
>
> This turns fast-path I/O into a lock-less RCU reader using existing
> percpu based se_lun->lun_ref logic, and converts the RCU updater
> path to allow for an arbitrary number of LUNs for both types of
> mappings within target-core.
>
> As per this afternoon's email thread, the se_dev_entry->pr_comp
> has been left in place for se_dev_entry shutdown within patch #1.
> This completion is still required in order to prevent the configfs
> se_lun_acl->se_lun_group from being removed from out below the
> core_scsi3_lunacl_depend_item() caller during the special-case PR
> ALL_TG_PT=1 registration handling.
>
> The changes based on -v2 series feedback from HCH & Co include:
>
> - Remove unused se_dev_entry->se_node_acl
> - Drop unnecessary check in lunacl_undepend_item
> - target: Drop bogus mutex_unlock in core_disable_device_list_for_node
> - Drop left-over se_lun->lun_status
> - target: Rename ->pr_regs to ->deve_flags + add bit definitions
> - target: Convert se_dev_entry stats to atomic_long_t
> - Avoid unnecessary PR target_nacl_find_deve() lookup in registration
> - Add se_lun->lun_index for RCU dev->dev_index usage in stat.c
> - Add various rcu_dereference and lockless_dereference RCU notation
>
> Please review.
>
> --nab
>
For the whole series:

Reviewed-by: Hannes Reinecke <hare@xxxxxxx>

Do you have a git tree for these changes?
As mentioned earlier, it should be fairly trivial to convert
LIO target to use 64-bit LUNs with this patchset.

Cheers,

Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@xxxxxxx +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
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HRB 21284 (AG Nürnberg)
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