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Date: Wed, 11 Apr 2012 17:41:13 -0700 (PDT)
From: Hugh Dickins <hughd@google.com>
X-X-Sender: hugh@eggly.anvils
To: Cong Wang <xiyou.wangcong@gmail.com>
cc: linux-kernel@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>,
        Oleg Nesterov <oleg@redhat.com>, Alexey Dobriyan <adobriyan@gmail.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Vasiliy Kulikov <segoon@openwall.com>,
        David Rientjes <rientjes@google.com>,
        KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
        Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
        Siddhesh Poyarekar <siddhesh.poyarekar@gmail.com>
Subject: Re: [PATCH 6/6] proc: use IS_ERR_OR_NULL()
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References: <1334123976-11681-1-git-send-email-xiyou.wangcong@gmail.com> <1334123976-11681-6-git-send-email-xiyou.wangcong@gmail.com>
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On Wed, 11 Apr 2012, Cong Wang wrote:

> Cc: Oleg Nesterov <oleg@redhat.com>
> Cc: Alexey Dobriyan <adobriyan@gmail.com>
> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>

Whereas this one, I don't object, but I don't see it as an improvement.

> ---
>  fs/proc/base.c       |    2 +-
>  fs/proc/task_mmu.c   |    4 ++--
>  fs/proc/task_nommu.c |    2 +-
>  3 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> index 2dff86b..a72a409 100644
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -239,7 +239,7 @@ static int proc_pid_auxv(struct task_struct *task, char *buffer)
>  {
>  	struct mm_struct *mm = mm_access(task, PTRACE_MODE_READ);
>  	int res = PTR_ERR(mm);
> -	if (mm && !IS_ERR(mm)) {
> +	if (!IS_ERR_OR_NULL(mm)) {
>  		unsigned int nwords = 0;
>  		do {
>  			nwords += 2;
> diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
> index 03360a1..da4cf5f 100644
> --- a/fs/proc/task_mmu.c
> +++ b/fs/proc/task_mmu.c
> @@ -126,7 +126,7 @@ static void *m_start(struct seq_file *m, loff_t *pos)
>  		return ERR_PTR(-ESRCH);
>  
>  	mm = mm_access(priv->task, PTRACE_MODE_READ);
> -	if (!mm || IS_ERR(mm))
> +	if (IS_ERR_OR_NULL(mm))
>  		return mm;
>  	down_read(&mm->mmap_sem);
>  
> @@ -916,7 +916,7 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
>  
>  	mm = mm_access(task, PTRACE_MODE_READ);
>  	ret = PTR_ERR(mm);
> -	if (!mm || IS_ERR(mm))
> +	if (IS_ERR_OR_NULL(mm))
>  		goto out_free;
>  
>  	pagemap_walk.pmd_entry = pagemap_pte_range;
> diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
> index 1ccfa53..57ad3cf 100644
> --- a/fs/proc/task_nommu.c
> +++ b/fs/proc/task_nommu.c
> @@ -224,7 +224,7 @@ static void *m_start(struct seq_file *m, loff_t *pos)
>  		return ERR_PTR(-ESRCH);
>  
>  	mm = mm_access(priv->task, PTRACE_MODE_READ);
> -	if (!mm || IS_ERR(mm)) {
> +	if (IS_ERR_OR_NULL(mm)) {
>  		put_task_struct(priv->task);
>  		priv->task = NULL;
>  		return mm;
> -- 
> 1.7.7.6
> 
>