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| author | Nicholas Bellinger <nab@linux-iscsi.org> | 2015-05-19 00:03:07 -0700 |
|---|---|---|
| committer | Nicholas Bellinger <nab@linux-iscsi.org> | 2015-06-01 00:27:38 -0700 |
| commit | 4cc987eaff9144182cde88d6d132420c28d3f81b (patch) | |
| tree | 15cf7d432599e1e09446462968ef01c4d10a087e /drivers/target/target_core_alua.c | |
| parent | adf653f92f38e80a78bb77e912d49bcc8055330f (diff) | |
| download | talos-obmc-linux-4cc987eaff9144182cde88d6d132420c28d3f81b.tar.gz talos-obmc-linux-4cc987eaff9144182cde88d6d132420c28d3f81b.zip | |
target: Drop lun_sep_lock for se_lun->lun_se_dev RCU usage
With se_port and t10_alua_tg_pt_gp_member being absored into se_lun,
there is no need for an extra lock to protect se_lun->lun_se_dev
assignment.
This patch also converts backend drivers to use call_rcu() release
to allow any se_device readers to complete. The call_rcu() instead
of kfree_rcu() is required here because se_device is embedded into
the backend driver specific structure.
Also, convert se_lun->lun_stats to use atomic_long_t within the
target_complete_ok_work() completion callback, and add FIXME for
transport_lookup_tmr_lun() with se_lun->lun_ref.
Finally, update sbp_update_unit_directory() special case usage with
proper rcu_dereference_raw() and configfs symlink comment.
Reported-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Chris Boot <bootc@bootc.net>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/target/target_core_alua.c')
| -rw-r--r-- | drivers/target/target_core_alua.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/drivers/target/target_core_alua.c b/drivers/target/target_core_alua.c index 1109c2833fe6..0a0087311cfb 100644 --- a/drivers/target/target_core_alua.c +++ b/drivers/target/target_core_alua.c @@ -1935,7 +1935,11 @@ ssize_t core_alua_store_tg_pt_gp_info( size_t count) { struct se_portal_group *tpg = lun->lun_tpg; - struct se_device *dev = lun->lun_se_dev; + /* + * rcu_dereference_raw protected by se_lun->lun_group symlink + * reference to se_device->dev_group. + */ + struct se_device *dev = rcu_dereference_raw(lun->lun_se_dev); struct t10_alua_tg_pt_gp *tg_pt_gp = NULL, *tg_pt_gp_new = NULL; unsigned char buf[TG_PT_GROUP_NAME_BUF]; int move = 0; @@ -2189,7 +2193,11 @@ ssize_t core_alua_store_offline_bit( const char *page, size_t count) { - struct se_device *dev = lun->lun_se_dev; + /* + * rcu_dereference_raw protected by se_lun->lun_group symlink + * reference to se_device->dev_group. + */ + struct se_device *dev = rcu_dereference_raw(lun->lun_se_dev); unsigned long tmp; int ret; |
