From 10e9cbb6b531117be0c4a79f2c7fa9a45a0dd532 Mon Sep 17 00:00:00 2001
From: Matthew Wilcox
Date: Tue, 12 Jun 2018 12:05:44 -0700
Subject: scsi: target: Convert target drivers to use sbitmap

The sbitmap and the percpu_ida perform essentially the same task,
allocating tags for commands.  The sbitmap outperforms the percpu_ida as
documented here: https://lkml.org/lkml/2014/4/22/553

The sbitmap interface is a little harder to use, but being able to remove
the percpu_ida code and getting better performance justifies the additional
complexity.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>	# f_tcm
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
---
 include/target/iscsi/iscsi_target_core.h | 1 +
 include/target/target_core_base.h        | 7 ++++---
 2 files changed, 5 insertions(+), 3 deletions(-)

(limited to 'include/target')

diff --git a/include/target/iscsi/iscsi_target_core.h b/include/target/iscsi/iscsi_target_core.h
index cf5f3fff1f1a..f2e6abea8490 100644
--- a/include/target/iscsi/iscsi_target_core.h
+++ b/include/target/iscsi/iscsi_target_core.h
@@ -4,6 +4,7 @@
 
 #include <linux/dma-direction.h>     /* enum dma_data_direction */
 #include <linux/list.h>              /* struct list_head */
+#include <linux/sched.h>
 #include <linux/socket.h>            /* struct sockaddr_storage */
 #include <linux/types.h>             /* u8 */
 #include <scsi/iscsi_proto.h>        /* itt_t */
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 260c2f3e9460..448f291125c2 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -4,7 +4,7 @@
 
 #include <linux/configfs.h>      /* struct config_group */
 #include <linux/dma-direction.h> /* enum dma_data_direction */
-#include <linux/percpu_ida.h>    /* struct percpu_ida */
+#include <linux/sbitmap.h>
 #include <linux/percpu-refcount.h>
 #include <linux/semaphore.h>     /* struct semaphore */
 #include <linux/completion.h>
@@ -455,6 +455,7 @@ struct se_cmd {
 	int			sam_task_attr;
 	/* Used for se_sess->sess_tag_pool */
 	unsigned int		map_tag;
+	int			map_cpu;
 	/* Transport protocol dependent state, see transport_state_table */
 	enum transport_state_table t_state;
 	/* See se_cmd_flags_table */
@@ -608,7 +609,7 @@ struct se_session {
 	struct list_head	sess_wait_list;
 	spinlock_t		sess_cmd_lock;
 	void			*sess_cmd_map;
-	struct percpu_ida	sess_tag_pool;
+	struct sbitmap_queue	sess_tag_pool;
 };
 
 struct se_device;
@@ -936,7 +937,7 @@ static inline void atomic_dec_mb(atomic_t *v)
 
 static inline void target_free_tag(struct se_session *sess, struct se_cmd *cmd)
 {
-	percpu_ida_free(&sess->sess_tag_pool, cmd->map_tag);
+	sbitmap_queue_clear(&sess->sess_tag_pool, cmd->map_tag, cmd->map_cpu);
 }
 
 #endif /* TARGET_CORE_BASE_H */
-- 
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