On Mon, 02 Nov 2009 10:45:36 -0700
Bjorn Helgaas <bjorn.helgaas@xxxxxx> wrote:
> 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.
>
> Signed-off-by: Bjorn Helgaas <bjorn.helgaas@xxxxxx>
> ---
> kernel/resource.c | 26 ++++++++++++++------------
> 1 files changed, 14 insertions(+), 12 deletions(-)
>
> diff --git a/kernel/resource.c b/kernel/resource.c
> index fb11a58..dc15686 100644
> --- a/kernel/resource.c
> +++ b/kernel/resource.c
> @@ -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;
Seems like a reasonable change to me. Linus is usually the gatekeeper
for resource.c.
--
Jesse Barnes, Intel Open Source Technology Center
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
