Re: [PATCH linux-next v2] ocfs2: remove kfree() redundant nullchecks

From: Andrew Morton
Date: Wed Feb 13 2013 - 18:53:30 EST


On Wed, 13 Feb 2013 13:29:45 -0700
Tim Gardner <tim.gardner@xxxxxxxxxxxxx> wrote:

> smatch analysis indicates a number of redundant NULL checks before
> calling kfree(), e.g.,
>
> fs/ocfs2/alloc.c:6138 ocfs2_begin_truncate_log_recovery() info:
> redundant null check on *tl_copy calling kfree()
>
> fs/ocfs2/alloc.c:6755 ocfs2_zero_range_for_truncate() info:
> redundant null check on pages calling kfree()
>
> ...
>
> diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
> index 31b9463..83a1a1d 100644
> --- a/fs/ocfs2/alloc.c
> +++ b/fs/ocfs2/alloc.c
> @@ -6134,7 +6134,7 @@ bail:
> iput(tl_inode);
> brelse(tl_bh);
>
> - if (status < 0 && (*tl_copy)) {
> + if (status < 0) {
> kfree(*tl_copy);
> *tl_copy = NULL;
> mlog_errno(status);

This change does other things. For example, if
ocfs2_begin_truncate_log_recovery()'s first "goto bail" is taken, we
will now call mlog_errno(status) twice.

That function is pretty confused about its error recovery and logging.
it needs some maintenance. I'll omit this hunk of your patch.


> @@ -534,7 +533,7 @@ int ocfs2_begin_local_alloc_recovery(struct ocfs2_super *osb,
> mlog_errno(status);
>
> bail:
> - if ((status < 0) && (*alloc_copy)) {
> + if (status < 0) {
> kfree(*alloc_copy);
> *alloc_copy = NULL;
> }

Similar, but this change lokos OK.


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