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

From: Nicholas A. Bellinger
Date: Mon Jun 01 2015 - 04:32:50 EST


On Tue, 2015-05-26 at 11:41 +0200, Hannes Reinecke wrote:
> 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>

Thanks for reviewing. 8-)

>
> 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.
>

The latest -v4 + -v3 series changes from this morning have been pushed
to target-pending/for-next.

Thank you,

--nab

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