On Tue, Mar 31, 2015 at 11:51:56PM -0700, Nicholas A. Bellinger wrote: > Since last week, enable/disable device_list code has been converted to > use mempool + call_rcu() and performs the RCU pointer swap in > se_node_acl->lun_entry_hlist[] under se_node_acl->lun_entry_mutex. Why use a mempool there? Please take a look at my branch, it's much simpler and logical than the old version. > There are a few more target_core_pr.c pieces that need to be updated to > handle NULL se_node_acl->lun_entry_hlist[] pointers, along with proper > rcu_dereference_protected() and rcu_access_pointer() notations for > se_dev_entry pointer access outside of RCU read lock. In my branch I've been over all the places to make sure they handle the NULL case. > > that implements this scheme. Note that I dropped the percpu refcount > > changes - the reference is only taken in the SCSI3-PR slow path, and the > > percpu refcount API is extremly cumbersome. > > > > Well, there still needs to be some manner of reference counting on > se_dev_entry once rcu_read_lock() is released for the REGISTER w/ I_PORT > and REGISTER_AND_MOVE cases with a non-local I_T_L se_dev_entry > reference. The refcount is still there in the good old atomic_t-based version, which is perfectl fine for the PRIN and PROUT subcommands which aren't the I/O fast path. -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
