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| author | Mike Christie <michael.christie@oracle.com> | 2021-02-27 18:00:02 +0100 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2021-03-04 23:37:02 +0100 |
| commit | 302990ac3b1b1a2b7b66f59a5c88038a51fbe18e (patch) | |
| tree | be970c2bc90c9b7f68cc2c2217c2f5168bbdc68b /drivers/target | |
| parent | scsi: target: core: Cleanup cmd flag bits (diff) | |
| download | linux-302990ac3b1b1a2b7b66f59a5c88038a51fbe18e.tar.xz linux-302990ac3b1b1a2b7b66f59a5c88038a51fbe18e.zip | |
scsi: target: core: Fix backend plugging
target_core_iblock is plugging and unplugging on every command and this is
causing perf issues for drivers that prefer batched cmds. With recent
patches we can now take multiple cmds from a fabric driver queue and then
pass them down the backend drivers in a batch. This patch adds this support
by adding 2 callouts to the backend for plugging and unplugging the
device. Subsequent commits will add support for iblock and tcmu device
plugging.
Link: https://lore.kernel.org/r/20210227170006.5077-22-michael.christie@oracle.com
Reviewed-by: Bodo Stroesser <bostroesser@gmail.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/target')
| -rw-r--r-- | drivers/target/target_core_transport.c | 43 |
1 files changed, 42 insertions, 1 deletions
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index eea7c27dc4cd..1245c288d3bf 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -1807,10 +1807,42 @@ void target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess, } EXPORT_SYMBOL(target_submit_cmd); + +static struct se_dev_plug *target_plug_device(struct se_device *se_dev) +{ + struct se_dev_plug *se_plug; + + if (!se_dev->transport->plug_device) + return NULL; + + se_plug = se_dev->transport->plug_device(se_dev); + if (!se_plug) + return NULL; + + se_plug->se_dev = se_dev; + /* + * We have a ref to the lun at this point, but the cmds could + * complete before we unplug, so grab a ref to the se_device so we + * can call back into the backend. + */ + config_group_get(&se_dev->dev_group); + return se_plug; +} + +static void target_unplug_device(struct se_dev_plug *se_plug) +{ + struct se_device *se_dev = se_plug->se_dev; + + se_dev->transport->unplug_device(se_plug); + config_group_put(&se_dev->dev_group); +} + void target_queued_submit_work(struct work_struct *work) { struct se_cmd_queue *sq = container_of(work, struct se_cmd_queue, work); struct se_cmd *se_cmd, *next_cmd; + struct se_dev_plug *se_plug = NULL; + struct se_device *se_dev = NULL; struct llist_node *cmd_list; cmd_list = llist_del_all(&sq->cmd_list); @@ -1819,8 +1851,17 @@ void target_queued_submit_work(struct work_struct *work) return; cmd_list = llist_reverse_order(cmd_list); - llist_for_each_entry_safe(se_cmd, next_cmd, cmd_list, se_cmd_list) + llist_for_each_entry_safe(se_cmd, next_cmd, cmd_list, se_cmd_list) { + if (!se_dev) { + se_dev = se_cmd->se_dev; + se_plug = target_plug_device(se_dev); + } + target_submit(se_cmd); + } + + if (se_plug) + target_unplug_device(se_plug); } /** |