Messages in this thread | | | Subject | Re: [PATCH 01/12] target: Convert se_node_acl->device_list[] to RCU hlist | From | "Nicholas A. Bellinger" <> | Date | Tue, 12 May 2015 22:08:51 -0700 |
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On Tue, 2015-05-12 at 13:58 -0700, Andy Grover wrote: > On 05/12/2015 02:25 AM, Nicholas A. Bellinger wrote: > > From: Nicholas Bellinger <nab@linux-iscsi.org> > > > > This patch converts se_node_acl->device_list[] table for mappedluns > > to modern RCU hlist_head usage in order to support an arbitrary number > > of node_acl lun mappings. > > > > This includes changes to core_[enable,disable]_device_list_for_node() > > rcu_assign_pointer() and invokes call_rcu() for releasing memory, along > > with a number of RCU read path conversions in target_core_device.c code. > > > > Required for subsequent conversion of transport_lookup_cmd() to lock-less > > RCU read path. > > > > Cc: Hannes Reinecke <hare@suse.de> > > Cc: Christoph Hellwig <hch@lst.de> > > Cc: Sagi Grimberg <sagig@mellanox.com> > > Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
<SNIP>
> > diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h > > index 042a734..6fb38df 100644 > > --- a/include/target/target_core_base.h > > +++ b/include/target/target_core_base.h > > @@ -584,10 +584,12 @@ struct se_node_acl { > > char acl_tag[MAX_ACL_TAG_SIZE]; > > /* Used for PR SPEC_I_PT=1 and REGISTER_AND_MOVE */ > > atomic_t acl_pr_ref_count; > > + struct hlist_head lun_entry_hlist; > > struct se_dev_entry **device_list; > > Very nice to see all this posted! > > Patch 6 is where device_list is finally removed. Suggest squashing 1-6, > maybe after review, I'm guessing they're not bisectable. >
The series is bisectable. With patch #1 in place ->device_list[] is still kzalloc()'ed, but new RCU pointer assignments are made into lun_entry_hlist[].
Squashing the RCU reader paths (#2-6) for merge is OK, but it's still nice to break up reader / updater changes into separate patches.
--nab
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