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Christophe JAILLET

2022-Jul-19 10:01 UTC

[Ocfs2-devel] [PATCH 1/3] ocfs2: Remove some useless functions

__ocfs2_node_map_set_bit() and __ocfs2_node_map_set_bit() are just
wrapper around set_bit() and clear_bit().

The leading __ also makes think that these functions are non-atomic just
like __set_bit() and __clear_bit().

So, just remove these wrappers and call set_bit() and clear_bit()
directly.

Signed-off-by: Christophe JAILLET <christophe.jaillet at wanadoo.fr>
---
 fs/ocfs2/heartbeat.c | 21 ++-------------------
 1 file changed, 2 insertions(+), 19 deletions(-)

diff --git a/fs/ocfs2/heartbeat.c b/fs/ocfs2/heartbeat.c
index 9099d8fc7599..1d72e0788943 100644
--- a/fs/ocfs2/heartbeat.c
+++ b/fs/ocfs2/heartbeat.c
@@ -24,11 +24,6 @@
 
 #include "buffer_head_io.h"
 
-static inline void __ocfs2_node_map_set_bit(struct ocfs2_node_map *map,
-					    int bit);
-static inline void __ocfs2_node_map_clear_bit(struct ocfs2_node_map *map,
-					      int bit);
-
 /* special case -1 for now
  * TODO: should *really* make sure the calling func never passes -1!!  */
 static void ocfs2_node_map_init(struct ocfs2_node_map *map)
@@ -65,12 +60,6 @@ void ocfs2_do_node_down(int node_num, void *data)
 	ocfs2_recovery_thread(osb, node_num);
 }
 
-static inline void __ocfs2_node_map_set_bit(struct ocfs2_node_map *map,
-					    int bit)
-{
-	set_bit(bit, map->map);
-}
-
 void ocfs2_node_map_set_bit(struct ocfs2_super *osb,
 			    struct ocfs2_node_map *map,
 			    int bit)
@@ -79,16 +68,10 @@ void ocfs2_node_map_set_bit(struct ocfs2_super *osb,
 		return;
 	BUG_ON(bit >= map->num_nodes);
 	spin_lock(&osb->node_map_lock);
-	__ocfs2_node_map_set_bit(map, bit);
+	set_bit(bit, map->map);
 	spin_unlock(&osb->node_map_lock);
 }
 
-static inline void __ocfs2_node_map_clear_bit(struct ocfs2_node_map *map,
-					      int bit)
-{
-	clear_bit(bit, map->map);
-}
-
 void ocfs2_node_map_clear_bit(struct ocfs2_super *osb,
 			      struct ocfs2_node_map *map,
 			      int bit)
@@ -97,7 +80,7 @@ void ocfs2_node_map_clear_bit(struct ocfs2_super *osb,
 		return;
 	BUG_ON(bit >= map->num_nodes);
 	spin_lock(&osb->node_map_lock);
-	__ocfs2_node_map_clear_bit(map, bit);
+	clear_bit(bit, map->map);
 	spin_unlock(&osb->node_map_lock);
 }
 
-- 
2.34.1

Christophe JAILLET

2022-Jul-19 10:01 UTC

head link

[Ocfs2-devel] [PATCH 2/3] ocfs2: Remove a useless spinlock

'node_map_lock' is a spinlock only used to protect calls to set_bit(),
clear_bit() and test_bit().

{set|clear}_bit() are already atomic and don't need this extra spinlock.
test_bit() only reads the bitmap for a given bit.

Remove this useless spinlock.

Signed-off-by: Christophe JAILLET <christophe.jaillet at wanadoo.fr>
---
test_bit() is NOT documented as an atomic function. However, I can't see
how it could return a wrong result here.

So review with care. There is maybe something I don't think about that is
lurking here.
---
 fs/ocfs2/heartbeat.c | 11 ++++-------
 fs/ocfs2/ocfs2.h     |  2 --
 2 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/fs/ocfs2/heartbeat.c b/fs/ocfs2/heartbeat.c
index 1d72e0788943..4863ad35c242 100644
--- a/fs/ocfs2/heartbeat.c
+++ b/fs/ocfs2/heartbeat.c
@@ -35,7 +35,6 @@ static void ocfs2_node_map_init(struct ocfs2_node_map *map)
 
 void ocfs2_init_node_maps(struct ocfs2_super *osb)
 {
-	spin_lock_init(&osb->node_map_lock);
 	ocfs2_node_map_init(&osb->osb_recovering_orphan_dirs);
 }
 
@@ -67,9 +66,8 @@ void ocfs2_node_map_set_bit(struct ocfs2_super *osb,
 	if (bit==-1)
 		return;
 	BUG_ON(bit >= map->num_nodes);
-	spin_lock(&osb->node_map_lock);
+
 	set_bit(bit, map->map);
-	spin_unlock(&osb->node_map_lock);
 }
 
 void ocfs2_node_map_clear_bit(struct ocfs2_super *osb,
@@ -79,9 +77,8 @@ void ocfs2_node_map_clear_bit(struct ocfs2_super *osb,
 	if (bit==-1)
 		return;
 	BUG_ON(bit >= map->num_nodes);
-	spin_lock(&osb->node_map_lock);
+
 	clear_bit(bit, map->map);
-	spin_unlock(&osb->node_map_lock);
 }
 
 int ocfs2_node_map_test_bit(struct ocfs2_super *osb,
@@ -89,13 +86,13 @@ int ocfs2_node_map_test_bit(struct ocfs2_super *osb,
 			    int bit)
 {
 	int ret;
+
 	if (bit >= map->num_nodes) {
 		mlog(ML_ERROR, "bit=%d map->num_nodes=%d\n", bit,
map->num_nodes);
 		BUG();
 	}
-	spin_lock(&osb->node_map_lock);
+
 	ret = test_bit(bit, map->map);
-	spin_unlock(&osb->node_map_lock);
 	return ret;
 }
 
diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index 740b64238312..1df193b97c30 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -302,8 +302,6 @@ struct ocfs2_super
 
 	u32 *slot_recovery_generations;
 
-	spinlock_t node_map_lock;
-
 	u64 root_blkno;
 	u64 system_dir_blkno;
 	u64 bitmap_blkno;
-- 
2.34.1

Christophe JAILLET

2022-Jul-19 10:05 UTC

head link

[Ocfs2-devel] [PATCH 3/3] ocfs2: use the bitmap API to simplify code

Use bitmap_zero() instead of hand-writing it.
It is less verbose.

While at it, add an explicit #include <linux/bitmap.h>.

Signed-off-by: Christophe JAILLET <christophe.jaillet at wanadoo.fr>
---
 fs/ocfs2/heartbeat.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/ocfs2/heartbeat.c b/fs/ocfs2/heartbeat.c
index 4863ad35c242..e243cd99e63f 100644
--- a/fs/ocfs2/heartbeat.c
+++ b/fs/ocfs2/heartbeat.c
@@ -8,6 +8,7 @@
  * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
  */
 
+#include <linux/bitmap.h>
 #include <linux/fs.h>
 #include <linux/types.h>
 #include <linux/highmem.h>
@@ -29,8 +30,7 @@
 static void ocfs2_node_map_init(struct ocfs2_node_map *map)
 {
 	map->num_nodes = OCFS2_NODE_MAP_MAX_NODES;
-	memset(map->map, 0, BITS_TO_LONGS(OCFS2_NODE_MAP_MAX_NODES) *
-	       sizeof(unsigned long));
+	bitmap_zero(map->map, OCFS2_NODE_MAP_MAX_NODES);
 }
 
 void ocfs2_init_node_maps(struct ocfs2_super *osb)
-- 
2.34.1

Joseph Qi

2022-Jul-20 02:03 UTC

head link

[Ocfs2-devel] [PATCH 1/3] ocfs2: Remove some useless functions

On 7/19/22 6:01 PM, Christophe JAILLET wrote:> __ocfs2_node_map_set_bit() and __ocfs2_node_map_set_bit() are just
> wrapper around set_bit() and clear_bit().
> 
> The leading __ also makes think that these functions are non-atomic just
> like __set_bit() and __clear_bit().
> 
> So, just remove these wrappers and call set_bit() and clear_bit()
> directly.
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet at wanadoo.fr>
Looks good.
Reviewed-by: Joseph Qi <joseph.qi at linux.alibaba.com>
> ---
>  fs/ocfs2/heartbeat.c | 21 ++-------------------
>  1 file changed, 2 insertions(+), 19 deletions(-)
> 
> diff --git a/fs/ocfs2/heartbeat.c b/fs/ocfs2/heartbeat.c
> index 9099d8fc7599..1d72e0788943 100644
> --- a/fs/ocfs2/heartbeat.c
> +++ b/fs/ocfs2/heartbeat.c
> @@ -24,11 +24,6 @@
>  
>  #include "buffer_head_io.h"
>  
> -static inline void __ocfs2_node_map_set_bit(struct ocfs2_node_map *map,
> -					    int bit);
> -static inline void __ocfs2_node_map_clear_bit(struct ocfs2_node_map *map,
> -					      int bit);
> -
>  /* special case -1 for now
>   * TODO: should *really* make sure the calling func never passes -1!!  */
>  static void ocfs2_node_map_init(struct ocfs2_node_map *map)
> @@ -65,12 +60,6 @@ void ocfs2_do_node_down(int node_num, void *data)
>  	ocfs2_recovery_thread(osb, node_num);
>  }
>  
> -static inline void __ocfs2_node_map_set_bit(struct ocfs2_node_map *map,
> -					    int bit)
> -{
> -	set_bit(bit, map->map);
> -}
> -
>  void ocfs2_node_map_set_bit(struct ocfs2_super *osb,
>  			    struct ocfs2_node_map *map,
>  			    int bit)
> @@ -79,16 +68,10 @@ void ocfs2_node_map_set_bit(struct ocfs2_super *osb,
>  		return;
>  	BUG_ON(bit >= map->num_nodes);
>  	spin_lock(&osb->node_map_lock);
> -	__ocfs2_node_map_set_bit(map, bit);
> +	set_bit(bit, map->map);
>  	spin_unlock(&osb->node_map_lock);
>  }
>  
> -static inline void __ocfs2_node_map_clear_bit(struct ocfs2_node_map *map,
> -					      int bit)
> -{
> -	clear_bit(bit, map->map);
> -}
> -
>  void ocfs2_node_map_clear_bit(struct ocfs2_super *osb,
>  			      struct ocfs2_node_map *map,
>  			      int bit)
> @@ -97,7 +80,7 @@ void ocfs2_node_map_clear_bit(struct ocfs2_super *osb,
>  		return;
>  	BUG_ON(bit >= map->num_nodes);
>  	spin_lock(&osb->node_map_lock);
> -	__ocfs2_node_map_clear_bit(map, bit);
> +	clear_bit(bit, map->map);
>  	spin_unlock(&osb->node_map_lock);
>  }
>

Ocfs2 devel - Jul 2022 - [PATCH 2/3] ocfs2: Remove a useless spinlock

[Ocfs2-devel] [PATCH 1/3] ocfs2: Remove some useless functions

[Ocfs2-devel] [PATCH 2/3] ocfs2: Remove a useless spinlock

[Ocfs2-devel] [PATCH 3/3] ocfs2: use the bitmap API to simplify code

[Ocfs2-devel] [PATCH 1/3] ocfs2: Remove some useless functions