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libfs: Replace rcu_assign_pointer() with RCU_INIT_POINTER()

PATCH Applied Andreea-Cristina Bernat 3 participants 3 messages Aug 18, 2014 – Sep 30, 2014

Subsystems (2)
SCSI FCoE subsystem (libfc, libfcoe, fcoe)
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Andreea-Cristina Bernat

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#0 lore raw

PATCH 1/1 libfs: Replace rcu_assign_pointer() with RCU_INIT_POINTER()

The uses of "rcu_assign_pointer()" are NULLing out the pointers. According to RCU_INIT_POINTER()'s block comment:
"1. This use of RCU_INIT_POINTER() is NULLing out the pointer"
it is better to use it instead of rcu_assign_pointer() because it has a smaller overhead.

The following Coccinelle semantic patch was used:
@@
@@

- rcu_assign_pointer
+ RCU_INIT_POINTER
(..., NULL)

Signed-off-by Andreea-Cristina Bernat <[email protected]>
---
 drivers/scsi/libfc/fc_libfc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
drivers/scsi/libfc/fc_libfc.c +2 -2
index 8d65a51a..c11a638 100644
@@ -296,9 +296,9 @@ void fc_fc4_deregister_provider(enum fc_fh_type type, struct fc4_prov *prov)
 	BUG_ON(type >= FC_FC4_PROV_SIZE);
 	mutex_lock(&fc_prov_mutex);
 	if (prov->recv)
-		rcu_assign_pointer(fc_passive_prov[type], NULL);
+		RCU_INIT_POINTER(fc_passive_prov[type], NULL);
 	else
-		rcu_assign_pointer(fc_active_prov[type], NULL);
+		RCU_INIT_POINTER(fc_active_prov[type], NULL);
 	mutex_unlock(&fc_prov_mutex);
 	synchronize_rcu();
 }
Signature · 1 line
1.9.1
Acked-by on v1 1/1
#1 lore raw
Quoted 25 lines · Andreea-Cristina Bernat

The uses of "rcu_assign_pointer()" are NULLing out the pointers. According to RCU_INIT_POINTER()'s block comment:
"1. This use of RCU_INIT_POINTER() is NULLing out the pointer"
it is better to use it instead of rcu_assign_pointer() because it has a smaller overhead.

The following Coccinelle semantic patch was used:
@@
@@

- rcu_assign_pointer
+ RCU_INIT_POINTER
(..., NULL)

Signed-off-by Andreea-Cristina Bernat <[email protected]>
---
 drivers/scsi/libfc/fc_libfc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
drivers/scsi/libfc/fc_libfc.c +0 -0
index 8d65a51a..c11a638 100644
@@ -296,9 +296,9 @@ void fc_fc4_deregister_provider(enum fc_fh_type type, struct fc4_prov *prov)
 	BUG_ON(type >= FC_FC4_PROV_SIZE);

drivers/scsi/libfc/fc_libfc.c void fc_fc4_deregister_provider(enum fc_fh_type type, struct fc4_prov *prov) · line 304

Quoted 10 lines
drivers/scsi/libfc/fc_libfc.c +2 -2
 	mutex_lock(&fc_prov_mutex);
 	if (prov->recv)
-		rcu_assign_pointer(fc_passive_prov[type], NULL);
+		RCU_INIT_POINTER(fc_passive_prov[type], NULL);
 	else
-		rcu_assign_pointer(fc_active_prov[type], NULL);
+		RCU_INIT_POINTER(fc_active_prov[type], NULL);
 	mutex_unlock(&fc_prov_mutex);
 	synchronize_rcu();
 }

Looks like patch is not yet applied.

Acked-by Vasu Dev <[email protected]>