From 695434e1cbd57f404110bf4ab187a5127ffd79bb Mon Sep 17 00:00:00 2001
From: Nicholas Bellinger <nab@linux-iscsi.org>
Date: Fri, 3 Jun 2011 20:59:19 -0700
Subject: [PATCH] target: Add transport_handle_cdb_direct optimization
This patch adds a transport_handle_cdb_direct() optimization for mapping
and queueing tasks directly from within fabric processing context by calling
the newly exported transport_generic_new_cmd(). This currently expects to
be called from process context only, and will fail if called within interrupt
context.
This patch also leaves transport_generic_handle_cdb() unmodified for the
moment to function as expected with existing tcm_fc and ib_srpt fabrics,
and will be removed once these have been converted and tested with v4.1
code using transport_handle_cdb_direct().
Based on Andy's original patch here:
[PATCH 39/42] target: Call transport_new_cmd instead of adding to cmd queue
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
drivers/target/target_core_transport.c | 24 ++++++++++++++++++++++++
include/target/target_core_transport.h | 1 +
2 files changed, 25 insertions(+)
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index d42a98e4725b..1ae6eb7a621b 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -1842,11 +1842,35 @@ int transport_generic_handle_cdb(
printk(KERN_ERR "cmd->se_lun is NULL\n");
return -EINVAL;
}
+
transport_add_cmd_to_queue(cmd, TRANSPORT_NEW_CMD);
return 0;
}
EXPORT_SYMBOL(transport_generic_handle_cdb);
+/*
+ * Used by fabric module frontends to queue tasks directly.
+ * Many only be used from process context only
+ */
+int transport_handle_cdb_direct(
+ struct se_cmd *cmd)
+{
+ if (!cmd->se_lun) {
+ dump_stack();
+ printk(KERN_ERR "cmd->se_lun is NULL\n");
+ return -EINVAL;
+ }
+ if (in_interrupt()) {
+ dump_stack();
+ printk(KERN_ERR "transport_generic_handle_cdb cannot be called"
+ " from interrupt context\n");
+ return -EINVAL;
+ }
+
+ return transport_generic_new_cmd(cmd);
+}
+EXPORT_SYMBOL(transport_handle_cdb_direct);
+
/*
* Used by fabric module frontends defining a TFO->new_cmd_map() caller
* to queue up a newly setup se_cmd w/ TRANSPORT_NEW_CMD_MAP in order to
diff --git a/include/target/target_core_transport.h b/include/target/target_core_transport.h
index 604e669527b4..2aae76412377 100644
--- a/include/target/target_core_transport.h
+++ b/include/target/target_core_transport.h
@@ -166,6 +166,7 @@ extern void transport_init_se_cmd(struct se_cmd *,
extern void transport_free_se_cmd(struct se_cmd *);
extern int transport_generic_allocate_tasks(struct se_cmd *, unsigned char *);
extern int transport_generic_handle_cdb(struct se_cmd *);
+extern int transport_handle_cdb_direct(struct se_cmd *);
extern int transport_generic_handle_cdb_map(struct se_cmd *);
extern int transport_generic_handle_data(struct se_cmd *);
extern void transport_new_cmd_failure(struct se_cmd *);
--
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