Re: [PATCH 02/36] scsi,rcu: convert call_rcu(fc_rport_free_rcu) to kfree_rcu()

On Tue, Mar 22, 2011 at 10:28:33AM -0700, Robert Love wrote:

On Thu, 2011-03-17 at 20:41 -0700, Lai Jiangshan wrote:

quoted

The rcu callback fc_rport_free_rcu() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(fc_rport_free_rcu).

Signed-off-by: Lai Jiangshan <redacted>
---
 drivers/scsi/libfc/fc_rport.c |   14 +-------------
 1 files changed, 1 insertions(+), 13 deletions(-)

diff --git a/drivers/scsi/libfc/fc_rport.c b/drivers/scsi/libfc/fc_rport.c
index a7175ad..29abab0 100644
--- a/drivers/scsi/libfc/fc_rport.c
+++ b/drivers/scsi/libfc/fc_rport.c

@@ -151,18 +151,6 @@ static struct fc_rport_priv *fc_rport_create(struct fc_lport *lport,
 }
 
 /**
- * fc_rport_free_rcu() - Free a remote port
- * @rcu: The rcu_head structure inside the remote port
- */
-static void fc_rport_free_rcu(struct rcu_head *rcu)
-{
-	struct fc_rport_priv *rdata;
-
-	rdata = container_of(rcu, struct fc_rport_priv, rcu);
-	kfree(rdata);
-}
-
-/**
  * fc_rport_destroy() - Free a remote port after last reference is released
  * @kref: The remote port's kref
  */

@@ -171,7 +159,7 @@ static void fc_rport_destroy(struct kref *kref)
 	struct fc_rport_priv *rdata;
 
 	rdata = container_of(kref, struct fc_rport_priv, kref);
-	call_rcu(&rdata->rcu, fc_rport_free_rcu);
+	kfree_rcu(rdata, rcu);

I think this last line should be:

kfree_rcu(rdata, &rdata->rcu);

Hello, Robert,

I believe that it is correct as is.  The kfree_rcu() definition is as
follows:

#define kfree_rcu(ptr, rcu_head)					\
	__kfree_rcu(&((ptr)->rcu_head), offsetof(typeof(*(ptr)), rcu_head))

Then __kfree_rcu() encodes the offset into the rcu_head so that it can
be handled properly at the end of the grace period.

							Thanx, Paul