On Tue, Sep 25, 2018 at 12:39:06PM -0600, Jon Derrick wrote:
> Currently, a hotplug bridge will be given hpmemsize additional memory
> and hpiosize additional io if available, in order to satisfy any future
> hotplug allocation requirements.
>
> These calculations don't consider the current memory/io size of the
> hotplug bridge/slot, so hotplug bridges/slots which have downstream
> devices will be allocated their current allocation in addition to the
> hpmemsize value.
>
> This makes for possibly undesirable results with a mix of unoccupied and
> occupied slots (ex, with hpmemsize=2M):
>
> 02:03.0 PCI bridge: <-- Occupied
> Memory behind bridge: d6200000-d64fffff [size=3M]
> 02:04.0 PCI bridge: <-- Unoccupied
> Memory behind bridge: d6500000-d66fffff [size=2M]
>
> This change considers the current allocation size when using the
> hpmemsize/hpiosize parameters to make the reservations predictable for
> the mix of unoccupied and occupied slots:
>
> 02:03.0 PCI bridge: <-- Occupied
> Memory behind bridge: d6200000-d63fffff [size=2M]
> 02:04.0 PCI bridge: <-- Unoccupied
> Memory behind bridge: d6400000-d65fffff [size=2M]
>
> Signed-off-by: Jon Derrick <jonathan.derrick@xxxxxxxxx>
Applied to pci/hotplug for v4.20, thanks!
> ---
> v2->v3: Made the IO and mem size calculations nearly equivalent
>
> drivers/pci/setup-bus.c | 28 +++++++++++++++-------------
> 1 file changed, 15 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> index 79b1824..ed96043 100644
> --- a/drivers/pci/setup-bus.c
> +++ b/drivers/pci/setup-bus.c
> @@ -811,6 +811,8 @@ static struct resource *find_free_bus_resource(struct pci_bus *bus,
> static resource_size_t calculate_iosize(resource_size_t size,
> resource_size_t min_size,
> resource_size_t size1,
> + resource_size_t add_size,
> + resource_size_t children_add_size,
> resource_size_t old_size,
> resource_size_t align)
> {
> @@ -823,15 +825,18 @@ static resource_size_t calculate_iosize(resource_size_t size,
> #if defined(CONFIG_ISA) || defined(CONFIG_EISA)
> size = (size & 0xff) + ((size & ~0xffUL) << 2);
> #endif
> - size = ALIGN(size + size1, align);
> + size = size + size1;
> if (size < old_size)
> size = old_size;
> +
> + size = ALIGN(max(size, add_size) + children_add_size, align);
> return size;
> }
>
> static resource_size_t calculate_memsize(resource_size_t size,
> resource_size_t min_size,
> - resource_size_t size1,
> + resource_size_t add_size,
> + resource_size_t children_add_size,
> resource_size_t old_size,
> resource_size_t align)
> {
> @@ -841,7 +846,8 @@ static resource_size_t calculate_memsize(resource_size_t size,
> old_size = 0;
> if (size < old_size)
> size = old_size;
> - size = ALIGN(size + size1, align);
> +
> + size = ALIGN(max(size, add_size) + children_add_size, align);
> return size;
> }
>
> @@ -930,12 +936,10 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size,
> }
> }
>
> - size0 = calculate_iosize(size, min_size, size1,
> + size0 = calculate_iosize(size, min_size, size1, 0, 0,
> resource_size(b_res), min_align);
> - if (children_add_size > add_size)
> - add_size = children_add_size;
> - size1 = (!realloc_head || (realloc_head && !add_size)) ? size0 :
> - calculate_iosize(size, min_size, add_size + size1,
> + size1 = (!realloc_head || (realloc_head && !add_size && !children_add_size)) ? size0 :
> + calculate_iosize(size, min_size, size1, add_size, children_add_size,
> resource_size(b_res), min_align);
> if (!size0 && !size1) {
> if (b_res->start || b_res->end)
> @@ -1079,12 +1083,10 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
>
> min_align = calculate_mem_align(aligns, max_order);
> min_align = max(min_align, window_alignment(bus, b_res->flags));
> - size0 = calculate_memsize(size, min_size, 0, resource_size(b_res), min_align);
> + size0 = calculate_memsize(size, min_size, 0, 0, resource_size(b_res), min_align);
> add_align = max(min_align, add_align);
> - if (children_add_size > add_size)
> - add_size = children_add_size;
> - size1 = (!realloc_head || (realloc_head && !add_size)) ? size0 :
> - calculate_memsize(size, min_size, add_size,
> + size1 = (!realloc_head || (realloc_head && !add_size && !children_add_size)) ? size0 :
> + calculate_memsize(size, min_size, add_size, children_add_size,
> resource_size(b_res), add_align);
> if (!size0 && !size1) {
> if (b_res->start || b_res->end)
> --
> 1.8.3.1
>
