resources: when allocate_resource() fails, leave resource untouched (1e5ad967) · Commits · 戴 / test

When "allocate_resource(root, new, size, ...)" fails, we currently clobber "new". This is inconvenient for the caller, who might care about the original contents of the resource. For example, when pci_bus_alloc_resource() fails, the "can't allocate mem resource %pR" message from pci_assign_resources() currently contains junk for the resource start/end. This patch delays the "new" update until we're about to return success. Acked-by:

Linus Torvalds <torvalds@linux-foundation.org> Acked-by:

Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by:

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

Jesse Barnes <jbarnes@virtuousgeek.org>

kernel/resource.c

+14 −12

Original line number	Diff line number	Diff line
		@@ -308,35 +308,37 @@ static int find_resource(struct resource root, struct resource new,
		void *alignf_data)
		{
		struct resource *this = root->child;
		resource_size_t start, end;

		new->start = root->start;
		start = root->start;
		/*
		* Skip past an allocated resource that starts at 0, since the assignment
		* of this->start - 1 to new->end below would cause an underflow.
		*/
		if (this && this->start == 0) {
		new->start = this->end + 1;
		start = this->end + 1;
		this = this->sibling;
		}
		for(;;) {
		if (this)
		new->end = this->start - 1;
		end = this->start - 1;
		else
		new->end = root->end;
		if (new->start < min)
		new->start = min;
		if (new->end > max)
		new->end = max;
		new->start = ALIGN(new->start, align);
		end = root->end;
		if (start < min)
		start = min;
		if (end > max)
		end = max;
		start = ALIGN(start, align);
		if (alignf)
		alignf(alignf_data, new, size, align);
		if (new->start < new->end && new->end - new->start >= size - 1) {
		new->end = new->start + size - 1;
		if (start < end && end - start >= size - 1) {
		new->start = start;
		new->end = start + size - 1;
		return 0;
		}
		if (!this)
		break;
		new->start = this->end + 1;
		start = this->end + 1;
		this = this->sibling;
		}
		return -EBUSY;

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