From: Dave Hansen <dave.hansen@linux.intel.com>
To: linux-kernel@vger.kernel.org
Cc: thomas.lendacky@amd.com, mhocko@suse.com,
linux-nvdimm@lists.01.org,
Dave Hansen <dave.hansen@linux.intel.com>,
ying.huang@intel.com, linux-mm@kvack.org, zwisler@kernel.org,
fengguang.wu@intel.com, akpm@linux-foundation.org
Subject: [PATCH 1/9] mm/resource: return real error codes from walk failures
Date: Mon, 22 Oct 2018 13:13:19 -0700 [thread overview]
Message-ID: <20181022201319.471D7B85@viggo.jf.intel.com> (raw)
In-Reply-To: <20181022201317.8558C1D8@viggo.jf.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>
---
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 2018-10-22 13:12:21.000930395 -0700
+++ b/kernel/resource.c 2018-10-22 13:12:21.003930395 -0700
@@ -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;
start = (u64) start_pfn << PAGE_SHIFT;
end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
_
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next prev parent reply other threads:[~2018-10-22 20:18 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-22 20:13 [PATCH 0/9] Allow persistent memory to be used like normal RAM Dave Hansen
2018-10-22 20:13 ` Dave Hansen [this message]
2018-10-22 20:13 ` [PATCH 2/9] dax: kernel memory driver for mm ownership of DAX Dave Hansen
2018-10-23 1:56 ` Randy Dunlap
2018-10-22 20:13 ` [PATCH 3/9] dax: add more kmem device infrastructure Dave Hansen
2018-10-22 20:13 ` [PATCH 4/9] dax/kmem: allow PMEM devices to bind to KMEM driver Dave Hansen
2018-10-22 20:13 ` [PATCH 5/9] dax/kmem: add more nd dax kmem infrastructure Dave Hansen
2018-10-22 20:13 ` [PATCH 6/9] mm/memory-hotplug: allow memory resources to be children Dave Hansen
2018-10-22 20:13 ` [PATCH 7/9] dax/kmem: actually perform memory hotplug Dave Hansen
2018-10-22 20:13 ` [PATCH 8/9] dax/kmem: let walk_system_ram_range() search child resources Dave Hansen
2018-10-22 20:13 ` [PATCH 9/9] dax/kmem: actually enable the code in Makefile Dave Hansen
2018-10-23 1:05 ` [PATCH 0/9] Allow persistent memory to be used like normal RAM Dan Williams
2018-10-23 1:11 ` Dan Williams
2018-10-26 8:03 ` Xishi Qiu
2018-10-26 13:58 ` Dave Hansen
2018-10-27 4:45 ` Dan Williams
2018-10-23 18:12 ` Elliott, Robert (Persistent Memory)
2018-10-23 18:16 ` Dave Hansen
2018-10-23 18:58 ` Dan Williams
2018-10-26 5:42 ` Xishi Qiu
2018-10-26 9:03 ` Fengguang Wu
2018-10-27 11:00 ` Fengguang Wu
2018-10-31 5:11 ` Yang Shi
2018-12-03 9:22 ` Brice Goglin
2018-12-03 16:56 ` Dave Hansen
2018-12-03 17:16 ` Dan Williams
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