2014-10-05 03:02:56

by John de la Garza

Subject: [PATCH] fs: use kfree_rcu instead of i_callback

Since the callback is doing nothing more than calling kfree() we can
use kfree_rcu() instead of having to use a callback.

Signed-off-by: John de la Garza <[email protected]>
---
fs/inode.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/fs/inode.c b/fs/inode.c
index 26753ba..51deccd 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -250,12 +250,6 @@ void __destroy_inode(struct inode *inode)
}
EXPORT_SYMBOL(__destroy_inode);

-static void i_callback(struct rcu_head *head)
-{
- struct inode *inode = container_of(head, struct inode, i_rcu);
- kmem_cache_free(inode_cachep, inode);
-}
-
static void destroy_inode(struct inode *inode)
{
BUG_ON(!list_empty(&inode->i_lru));
@@ -263,7 +257,7 @@ static void destroy_inode(struct inode *inode)
if (inode->i_sb->s_op->destroy_inode)
inode->i_sb->s_op->destroy_inode(inode);
else
- call_rcu(&inode->i_rcu, i_callback);
+ kfree(inode, i_rcu);
}

/**
--
2.1.0

2014-10-05 03:48:10

by Al Viro

Subject: Re: [PATCH] fs: use kfree_rcu instead of i_callback

On Sat, Oct 04, 2014 at 11:00:42PM -0400, John de la Garza wrote:
> Since the callback is doing nothing more than calling kfree() we can
> use kfree_rcu() instead of having to use a callback.

Except that this

> - kmem_cache_free(inode_cachep, inode);

isn't kfree()...

2014-10-05 10:24:45

by Chuck Ebbert

Subject: Re: [PATCH] fs: use kfree_rcu instead of i_callback

On Sat, 4 Oct 2014 23:00:42 -0400
John de la Garza <[email protected]> wrote:

> Since the callback is doing nothing more than calling kfree() we can
> use kfree_rcu() instead of having to use a callback.
>
> Signed-off-by: John de la Garza <[email protected]>
> ---
> fs/inode.c | 8 +-------
> 1 file changed, 1 insertion(+), 7 deletions(-)
>
> diff --git a/fs/inode.c b/fs/inode.c
> index 26753ba..51deccd 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -250,12 +250,6 @@ void __destroy_inode(struct inode *inode)
> }
> EXPORT_SYMBOL(__destroy_inode);
>
> -static void i_callback(struct rcu_head *head)
> -{
> - struct inode *inode = container_of(head, struct inode, i_rcu);
> - kmem_cache_free(inode_cachep, inode);
> -}
> -
> static void destroy_inode(struct inode *inode)
> {
> BUG_ON(!list_empty(&inode->i_lru));
> @@ -263,7 +257,7 @@ static void destroy_inode(struct inode *inode)
> if (inode->i_sb->s_op->destroy_inode)
> inode->i_sb->s_op->destroy_inode(inode);
> else
> - call_rcu(&inode->i_rcu, i_callback);
> + kfree(inode, i_rcu);

Your description says "use kfree_rcu()" but that is kfree(). This won't
even compile.

And as Al pointed out, kfree() is not the same as kmem_cache_free().
So you'd need to invent kmem_cache_free_rcu() also. Not sure that
would have any value elsewhere.

> }
>
> /**