Discussion:
[PATCH] libfs: Replace rcu_assign_pointer() with RCU_INIT_POINTER()
Andreea-Cristina Bernat
2014-08-18 14:56:22 UTC
Permalink
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 <***@gmail.com>
---
drivers/scsi/libfc/fc_libfc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/libfc/fc_libfc.c b/drivers/scsi/libfc/fc_libfc.c
index 8d65a51a..c11a638 100644
--- a/drivers/scsi/libfc/fc_libfc.c
+++ b/drivers/scsi/libfc/fc_libfc.c
@@ -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();
}
--
1.9.1

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Vasu Dev
2014-09-25 22:01:11 UTC
Permalink
Post by Andreea-Cristina Bernat
The uses of "rcu_assign_pointer()" are NULLing out the pointers.
"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.
@@
@@
- rcu_assign_pointer
+ RCU_INIT_POINTER
(..., NULL)
---
drivers/scsi/libfc/fc_libfc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/libfc/fc_libfc.c b/drivers/scsi/libfc/fc_libfc.c
index 8d65a51a..c11a638 100644
--- a/drivers/scsi/libfc/fc_libfc.c
+++ b/drivers/scsi/libfc/fc_libfc.c
@@ -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();
}
Looks like patch is not yet applied.

Acked-by: Vasu Dev <vasu.dev-***@public.gmane.org>
Christoph Hellwig
2014-09-30 15:36:54 UTC
Permalink
Thanks,

applied to drivers-for-3.18

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