From: Dan Williams <dan.j.williams@intel.com>
To: linux-acpi@vger.kernel.org
Cc: Jason Gunthorpe <jgg@ziepe.ca>,
Dave Hansen <dave.hansen@linux.intel.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
peterz@infradead.org, ard.biesheuvel@linaro.org,
linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org,
x86@kernel.org, joao.m.martins@oracle.com
Subject: [PATCH v2 5/6] resource: Report parent to walk_iomem_res_desc() callback
Date: Sun, 22 Mar 2020 09:12:53 -0700 [thread overview]
Message-ID: <158489357311.1457606.12568065258967741013.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)
In-Reply-To: <158489354353.1457606.8327903161927980740.stgit@dwillia2-desk3.amr.corp.intel.com>
In support of detecting whether a resource might have been been claimed,
report the parent to the walk_iomem_res_desc() callback. For example,
the ACPI HMAT parser publishes "hmem" platform devices per target range.
However, if the HMAT is disabled / missing a fallback driver can attach
devices to the raw memory ranges as a fallback if it sees unclaimed /
orphan "Soft Reserved" resources in the resource tree.
Otherwise, find_next_iomem_res() returns a resource with garbage data
from the stack allocation in __walk_iomem_res_desc() for the res->parent
field.
There are currently no users that expect ->child and ->sibling to be
valid, and the resource_lock would be needed to traverse them. Use a
compound literal to implicitly zero initialize the fields that are not
being returned in addition to setting ->parent.
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Wei Yang <richardw.yang@linux.intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
kernel/resource.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/kernel/resource.c b/kernel/resource.c
index 76036a41143b..f54ccf7a1009 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -382,10 +382,13 @@ static int find_next_iomem_res(resource_size_t start, resource_size_t end,
if (p) {
/* copy data */
- res->start = max(start, p->start);
- res->end = min(end, p->end);
- res->flags = p->flags;
- res->desc = p->desc;
+ *res = (struct resource) {
+ .start = max(start, p->start),
+ .end = min(end, p->end),
+ .flags = p->flags,
+ .desc = p->desc,
+ .parent = p->parent,
+ };
}
read_unlock(&resource_lock);
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next prev parent reply other threads:[~2020-03-22 16:29 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-22 16:12 [PATCH v2 0/6] Manual definition of Soft Reserved memory devices Dan Williams
2020-03-22 16:12 ` [PATCH v2 1/6] x86/numa: Cleanup configuration dependent command-line options Dan Williams
2020-03-22 16:12 ` [PATCH v2 2/6] x86/numa: Add 'nohmat' option Dan Williams
2020-03-22 16:12 ` [PATCH v2 3/6] efi/fake_mem: Arrange for a resource entry per efi_fake_mem instance Dan Williams
2020-03-22 16:12 ` [PATCH v2 4/6] ACPI: HMAT: Refactor hmat_register_target_device to hmem_register_device Dan Williams
2020-03-24 19:40 ` Joao Martins
2020-03-24 21:04 ` Dan Williams
2020-03-25 22:32 ` Dan Williams
2020-03-22 16:12 ` Dan Williams [this message]
2020-03-22 16:12 ` [PATCH v2 6/6] ACPI: HMAT: Attach a device for each soft-reserved range Dan Williams
2020-03-24 19:41 ` Joao Martins
2020-03-24 21:06 ` Dan Williams
2020-03-24 21:30 ` Joao Martins
2020-03-25 11:10 ` Will Deacon
2020-03-25 17:10 ` Dan Williams
2020-03-25 10:02 ` [PATCH v2 0/6] Manual definition of Soft Reserved memory devices Rafael J. Wysocki
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