Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 1e5ad967 authored by Bjorn Helgaas's avatar Bjorn Helgaas Committed by Jesse Barnes
Browse files

resources: when allocate_resource() fails, leave resource untouched 



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: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Acked-by: default avatarYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: default avatarBjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
parent 03db42ad

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;