From: Bjorn Helgaas <bhelgaas@google.com>
To: Dave Hansen <dave.hansen@linux.intel.com>
Cc: dave@sr71.net, Dan Williams <dan.j.williams@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
zwisler@kernel.org, vishal.l.verma@intel.com,
thomas.lendacky@amd.com,
Andrew Morton <akpm@linux-foundation.org>,
mhocko@suse.com, linux-nvdimm@lists.01.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org, Huang Ying <ying.huang@intel.com>,
Wu Fengguang <fengguang.wu@intel.com>,
Borislav Petkov <bp@suse.de>,
baiyaowei@cmss.chinamobile.com, Takashi Iwai <tiwai@suse.de>
Subject: Re: [PATCH 1/4] mm/resource: return real error codes from walk failures
Date: Wed, 16 Jan 2019 14:38:21 -0600 [thread overview]
Message-ID: <CAErSpo63av+jnkSY-V_ZNKy1LDX7rGZ6rK1bWbTf3fgrhXqrwQ@mail.gmail.com> (raw)
In-Reply-To: <20190116181901.CAF85066@viggo.jf.intel.com>
On Wed, Jan 16, 2019 at 12:25 PM Dave Hansen
<dave.hansen@linux.intel.com> wrote:
>
>
> From: Dave Hansen <dave.hansen@linux.intel.com>
>
> walk_system_ram_range() can return an error code either becuase *it*
> failed, or because the 'func' that it calls returned an error. The
> memory hotplug does the following:
>
> ret = walk_system_ram_range(..., func);
> if (ret)
> return ret;
>
> and 'ret' makes it out to userspace, eventually. The problem is,
> walk_system_ram_range() failues that result from *it* failing (as
> opposed to 'func') return -1. That leads to a very odd -EPERM (-1)
> return code out to userspace.
>
> Make walk_system_ram_range() return -EINVAL for internal failures to
> keep userspace less confused.
>
> This return code is compatible with all the callers that I audited.
>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Dave Jiang <dave.jiang@intel.com>
> Cc: Ross Zwisler <zwisler@kernel.org>
> Cc: Vishal Verma <vishal.l.verma@intel.com>
> Cc: Tom Lendacky <thomas.lendacky@amd.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: linux-nvdimm@lists.01.org
> Cc: linux-kernel@vger.kernel.org
> Cc: linux-mm@kvack.org
> Cc: Huang Ying <ying.huang@intel.com>
> Cc: Fengguang Wu <fengguang.wu@intel.com>
>
>
> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
> ---
>
> b/kernel/resource.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff -puN kernel/resource.c~memory-hotplug-walk_system_ram_range-returns-neg-1 kernel/resource.c
> --- a/kernel/resource.c~memory-hotplug-walk_system_ram_range-returns-neg-1 2018-12-20 11:48:41.810771934 -0800
> +++ b/kernel/resource.c 2018-12-20 11:48:41.814771934 -0800
> @@ -375,7 +375,7 @@ static int __walk_iomem_res_desc(resourc
> int (*func)(struct resource *, void *))
> {
> struct resource res;
> - int ret = -1;
> + int ret = -EINVAL;
>
> while (start < end &&
> !find_next_iomem_res(start, end, flags, desc, first_lvl, &res)) {
> @@ -453,7 +453,7 @@ int walk_system_ram_range(unsigned long
> unsigned long flags;
> struct resource res;
> unsigned long pfn, end_pfn;
> - int ret = -1;
> + int ret = -EINVAL;
Don't you want a similar change in the powerpc version in arch/powerpc/mm/mem.c?
>
> start = (u64) start_pfn << PAGE_SHIFT;
> end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
> _
next prev parent reply other threads:[~2019-01-16 20:38 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-16 18:18 [PATCH 0/4] Allow persistent memory to be used like normal RAM Dave Hansen
2019-01-16 18:19 ` [PATCH 1/4] mm/resource: return real error codes from walk failures Dave Hansen
2019-01-16 20:38 ` Bjorn Helgaas [this message]
2019-01-16 18:19 ` [PATCH 2/4] mm/memory-hotplug: allow memory resources to be children Dave Hansen
2019-01-16 19:16 ` Jerome Glisse
2019-01-16 23:01 ` Dave Hansen
2019-01-16 23:38 ` Jerome Glisse
2019-01-23 20:03 ` Dave Hansen
2019-01-23 20:15 ` Jerome Glisse
2019-01-18 19:58 ` Dave Hansen
2019-01-18 20:26 ` Jerome Glisse
2019-01-23 17:05 ` Michal Hocko
2019-01-16 18:19 ` [PATCH 3/4] dax/kmem: let walk_system_ram_range() search child resources Dave Hansen
2019-01-16 18:19 ` [PATCH 4/4] dax: "Hotplug" persistent memory for use like normal RAM Dave Hansen
2019-01-16 21:16 ` Bjorn Helgaas
2019-01-16 21:40 ` Dave Hansen
2019-01-16 21:44 ` Bjorn Helgaas
2019-01-16 22:06 ` Dan Williams
2019-01-16 21:53 ` Dave Hansen
2019-01-16 21:59 ` Bjorn Helgaas
2019-01-16 21:31 ` Dan Williams
2019-01-17 5:21 ` Du, Fan
2019-01-17 16:56 ` Dan Williams
2019-01-17 8:19 ` Yanmin Zhang
2019-01-17 15:17 ` Dave Hansen
2019-01-18 7:47 ` Yanmin Zhang
2019-01-18 15:20 ` Dave Hansen
2019-01-17 16:29 ` [PATCH 0/4] Allow persistent memory to be used " Jeff Moyer
2019-01-17 16:47 ` Keith Busch
2019-01-17 17:20 ` Jeff Moyer
2019-01-17 19:34 ` Keith Busch
2019-01-17 21:57 ` Jeff Moyer
2019-01-18 11:48 ` Fengguang Wu
2019-01-17 16:50 ` Dan Williams
2019-01-17 22:43 ` Dave Hansen
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