Re: [PATCH-v2 0/9] target: se_node_acl + se_lun RCU conversions

[Hannes Reinecke]

On 05/22/2015 08:11 AM, Nicholas A. Bellinger wrote:
> From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
> 
> Hi all,
> 
> Here is -v2 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.
> 
> This series also squashes a number of previous se_node_acl RCU
> related changes into a single commit (#1) for easier review,
> and to avoid potential bisect issues.
> 
> There have been a number of changes since -v1, including:
> 
>   - Mirror port->sep_rtpi in lun->lun_rtpi for RCU
>   - Drop unnecessary synchronize_rcu() usage
>   - Convert call_rcu() to kfree_rcu() usage
>   - Move hlist_del_rcu head of rcu_assign_pointer in se_dev_entry
>   - Drop unnecessary lookup deve in target_fabric_mappedlun_unlink()
>   - Add target_lun_is_rdonly helper
>   - Acquire lun_entry_mutex during core_disable_device_list_for_node
>   - Drop TRANSPORT_LUNFLAGS_*_ACCESS usage
>   - Pass se_dev_entry directly to core_disable_device_list_for_node
>   - Convert sbp-target se_lun usage to use ->login_lun
>   - Fix se_session dereference in spc_emulate_report_luns 
>   - Fix testing for NULL instead of IS_ERR in fabric_make_lun()
>   - Convert BUG_ON to EINVAL for wrong dynamic -> explicit ACL conversion 
>   - Add missing hlist_del_rcu when swapping orig with new
>   - Add HBA_FLAGS_INTERNAL_USE checks in add/remove lun
> 
> Please review.
> 
Very nice.

Reviewed-by: Hannes Reinecke <hare@xxxxxxx>

Although it would be _perfect_ if you could move to full 64-bit
LUNs; now that the LUN array is gone there is no need to have a
limitation on the number of LUNs, and we can trivially support
64-bit LUNs ...

But then, I can easily send a patch once this one is in.

Cheers,

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