linux-kernel - Re: [PATCH 1/2] lib/test: Delete five error messages for a failed memory allocation

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Date:   Mon, 9 Oct 2017 08:24:39 +0200
From:   Michal Hocko <mhocko@...nel.org>
To:     SF Markus Elfring <elfring@...rs.sourceforge.net>
Cc:     iommu@...ts.linux-foundation.org, kasan-dev@...glegroups.com,
        Alexander Potapenko <glider@...gle.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Christoph Hellwig <hch@....de>,
        Daniel Mentz <danielmentz@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Lars Ellenberg <lars.ellenberg@...bit.com>,
        "Luis R. Rodriguez" <mcgrof@...nel.org>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        Philipp Reisner <philipp.reisner@...bit.com>,
        Robin Murphy <robin.murphy@....com>,
        Will Deacon <will.deacon@....com>,
        LKML <linux-kernel@...r.kernel.org>,
        kernel-janitors@...r.kernel.org
Subject: Re: [PATCH 1/2] lib/test: Delete five error messages for a failed
 memory allocation

On Sat 07-10-17 19:48:37, SF Markus Elfring wrote:
> From: Markus Elfring <elfring@...rs.sourceforge.net>
> Date: Sat, 7 Oct 2017 17:34:23 +0200
> 
> Omit extra messages for a memory allocation failure in these functions.
> 
> This issue was detected by using the Coccinelle software.

Yes this makes sense. None of those really explain what the allocation
failure effect is. The allocation path already tells us about the
failure enough.

> Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>

Acked-by: Michal Hocko <mhocko@...e.com>

> ---
>  lib/test_kasan.c     | 5 ++---
>  lib/test_kmod.c      | 8 ++------
>  lib/test_list_sort.c | 9 +++------
>  3 files changed, 7 insertions(+), 15 deletions(-)
> 
> diff --git a/lib/test_kasan.c b/lib/test_kasan.c
> index a25c9763fce1..ef1a3ac1397e 100644
> --- a/lib/test_kasan.c
> +++ b/lib/test_kasan.c
> @@ -353,10 +353,9 @@ static noinline void __init memcg_accounted_kmem_cache(void)
>  	 */
>  	for (i = 0; i < 5; i++) {
>  		p = kmem_cache_alloc(cache, GFP_KERNEL);
> -		if (!p) {
> -			pr_err("Allocation failed\n");
> +		if (!p)
>  			goto free_cache;
> -		}
> +
>  		kmem_cache_free(cache, p);
>  		msleep(100);
>  	}
> diff --git a/lib/test_kmod.c b/lib/test_kmod.c
> index fba78d25e825..337f408b4de6 100644
> --- a/lib/test_kmod.c
> +++ b/lib/test_kmod.c
> @@ -783,10 +783,8 @@ static int kmod_config_sync_info(struct kmod_test_device *test_dev)
>  	free_test_dev_info(test_dev);
>  	test_dev->info = vzalloc(config->num_threads *
>  				 sizeof(struct kmod_test_device_info));
> -	if (!test_dev->info) {
> -		dev_err(test_dev->dev, "Cannot alloc test_dev info\n");
> +	if (!test_dev->info)
>  		return -ENOMEM;
> -	}
>  
>  	return 0;
>  }
> @@ -1089,10 +1087,8 @@ static struct kmod_test_device *alloc_test_dev_kmod(int idx)
>  	struct miscdevice *misc_dev;
>  
>  	test_dev = vzalloc(sizeof(struct kmod_test_device));
> -	if (!test_dev) {
> -		pr_err("Cannot alloc test_dev\n");
> +	if (!test_dev)
>  		goto err_out;
> -	}
>  
>  	mutex_init(&test_dev->config_mutex);
>  	mutex_init(&test_dev->trigger_mutex);
> diff --git a/lib/test_list_sort.c b/lib/test_list_sort.c
> index 28e817387b04..5474f3f3e41d 100644
> --- a/lib/test_list_sort.c
> +++ b/lib/test_list_sort.c
> @@ -76,17 +76,14 @@ static int __init list_sort_test(void)
>  	pr_debug("start testing list_sort()\n");
>  
>  	elts = kcalloc(TEST_LIST_LEN, sizeof(*elts), GFP_KERNEL);
> -	if (!elts) {
> -		pr_err("error: cannot allocate memory\n");
> +	if (!elts)
>  		return err;
> -	}
>  
>  	for (i = 0; i < TEST_LIST_LEN; i++) {
>  		el = kmalloc(sizeof(*el), GFP_KERNEL);
> -		if (!el) {
> -			pr_err("error: cannot allocate memory\n");
> +		if (!el)
>  			goto exit;
> -		}
> +
>  		 /* force some equivalencies */
>  		el->value = prandom_u32() % (TEST_LIST_LEN / 3);
>  		el->serial = i;
> -- 
> 2.14.2

-- 
Michal Hocko
SUSE Labs