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Subject[PATCH v3 1/6] resources: ensure alignment callback doesn't allocate below available start
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The alignment callback returns a proposed location, which may have been
adjusted to avoid ISA aliases or for other architecture-specific reasons.
We already had a check ("tmp.start < tmp.end") to make sure the callback
doesn't return a location above the available area.

This patch adds a check to make sure the callback doesn't return something
*below* the available area, as may happen if the callback tries to allocate
top-down.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
---

kernel/resource.c | 10 ++++++++--
1 files changed, 8 insertions(+), 2 deletions(-)


diff --git a/kernel/resource.c b/kernel/resource.c
index 7b36976..ace2269 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -371,6 +371,7 @@ static int find_resource(struct resource *root, struct resource *new,
{
struct resource *this = root->child;
struct resource tmp = *new;
+ resource_size_t start;

tmp.start = root->start;
/*
@@ -391,8 +392,13 @@ static int find_resource(struct resource *root, struct resource *new,
if (tmp.end > max)
tmp.end = max;
tmp.start = ALIGN(tmp.start, align);
- if (alignf)
- tmp.start = alignf(alignf_data, &tmp, size, align);
+ if (alignf) {
+ start = alignf(alignf_data, &tmp, size, align);
+ if (tmp.start <= start && start <= tmp.end)
+ tmp.start = start;
+ else
+ tmp.start = tmp.end;
+ }
if (tmp.start < tmp.end && tmp.end - tmp.start >= size - 1) {
new->start = tmp.start;
new->end = tmp.start + size - 1;


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