On Monday 20 December 2021 20:53:49 Pali Rohár wrote:
> Currently PCI domains are printed in ascending order. Devices on each PCI
> bus are also printed in ascending order. PCI buses behind PCI-to-PCI
> bridges are also printed in ascending order.
>
> But buses of PCI domain are currently printed in descending order because
> function new_bus() puts newly created bus at the beginning of linked list.
>
> In most cases PCI domain contains only one (top level) bus, so in most
> cases it is not visible this inconsistency.
>
> Multibus PCI domains (where PCI domain contains more independent top level
> PCI buses) are available on ARM devices.
>
> This change fixes print order of multibus PCI domains, so also top level
> PCI buses are printed in ascending order, like PCI buses behind PCI-to-PCI
> bridges.
> ---
> ls-tree.c | 10 +++++++---
> lspci.h | 2 +-
> 2 files changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/ls-tree.c b/ls-tree.c
> index aeb40870865e..17a95307b3fa 100644
> --- a/ls-tree.c
> +++ b/ls-tree.c
> @@ -12,7 +12,7 @@
>
> #include "lspci.h"
>
> -struct bridge host_bridge = { NULL, NULL, NULL, NULL, 0, ~0, 0, ~0, NULL };
> +struct bridge host_bridge = { NULL, NULL, NULL, NULL, NULL, 0, ~0, 0, ~0, NULL };
>
> static struct bus *
> find_bus(struct bridge *b, unsigned int domain, unsigned int n)
> @@ -31,11 +31,14 @@ new_bus(struct bridge *b, unsigned int domain, unsigned int n)
> struct bus *bus = xmalloc(sizeof(struct bus));
> bus->domain = domain;
> bus->number = n;
> - bus->sibling = b->first_bus;
Oops, this is a mistake. Default value for bus->sibling needs to be
explicitly set because xmalloc() wrapper does not return zero
initialized memory. So correct change for above line should be:
- bus->sibling = b->first_bus;
+ bus->sibling = NULL;
> bus->first_dev = NULL;
> bus->last_dev = &bus->first_dev;
> bus->parent_bridge = b;
> - b->first_bus = bus;
> + if (b->last_bus)
> + b->last_bus->sibling = bus;
> + b->last_bus = bus;
> + if (!b->first_bus)
> + b->first_bus = bus;
> return bus;
> }
>
> @@ -101,6 +104,7 @@ grow_tree(void)
> last_br = &b->chain;
> b->next = b->child = NULL;
> b->first_bus = NULL;
> + b->last_bus = NULL;
> b->br_dev = d;
> d->bridge = b;
> pacc->debug("Tree: bridge %04x:%02x:%02x.%d: %02x -> %02x-%02x\n",
> diff --git a/lspci.h b/lspci.h
> index fefee5256423..352177fcce7b 100644
> --- a/lspci.h
> +++ b/lspci.h
> @@ -90,7 +90,7 @@ void show_kernel_cleanup(void);
> struct bridge {
> struct bridge *chain; /* Single-linked list of bridges */
> struct bridge *next, *child; /* Tree of bridges */
> - struct bus *first_bus; /* List of buses connected to this bridge */
> + struct bus *first_bus, *last_bus; /* List of buses connected to this bridge */
> unsigned int domain;
> unsigned int primary, secondary, subordinate; /* Bus numbers */
> struct device *br_dev;
> --
> 2.20.1
>
