Messages in this thread Patch in this message | | | Subject | [PATCH 1/4] mm/resource: return real error codes from walk failures | From | Dave Hansen <> | Date | Wed, 16 Jan 2019 10:19:01 -0800 |
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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; start = (u64) start_pfn << PAGE_SHIFT; end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1; _
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