Re: [PATCH] no need to check for NULL before calling kfree() - fs/ext2/

[linux-os <linux-os@analogic.com>]

Isn't it expensive of CPU time to call kfree() even though the
pointer may have already been freed? I suggest that the check
for a NULL before the call is much less expensive than calling
kfree() and doing the check there. The resulting "double check"
is cheap, compared to the call.

On Fri, 25 Mar 2005, Jesper Juhl wrote:

> (please keep me on CC)
>
>
> kfree() handles NULL fine, to check is redundant.
>
> Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk>
>
> --- linux-2.6.12-rc1-mm3-orig/fs/ext2/acl.c	2005-03-02 08:38:18.000000000 +0100
> +++ linux-2.6.12-rc1-mm3/fs/ext2/acl.c	2005-03-25 22:41:07.000000000 +0100
> @@ -194,8 +194,7 @@ ext2_get_acl(struct inode *inode, int ty
> 		acl = NULL;
> 	else
> 		acl = ERR_PTR(retval);
> -	if (value)
> -		kfree(value);
> +	kfree(value);
>
> 	if (!IS_ERR(acl)) {
> 		switch(type) {
> @@ -262,8 +261,7 @@ ext2_set_acl(struct inode *inode, int ty
>
> 	error = ext2_xattr_set(inode, name_index, "", value, size, 0);
>
> -	if (value)
> -		kfree(value);
> +	kfree(value);
> 	if (!error) {
> 		switch(type) {
> 			case ACL_TYPE_ACCESS:
>
>
> -
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Cheers,
Dick Johnson
Penguin : Linux version 2.6.11 on an i686 machine (5537.79 BogoMips).
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