From 96336ec702643aec2addb3b1cdb81d687fe362f0 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Mon, 16 Dec 2024 19:56:31 +0200 Subject: [PATCH] PCI: Perform reset_resource() and build fail list in sync MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Resetting a resource is problematic as it prevents attempting to allocate the resource later, unless something in between restores the resource. Similarly, if fail_head does not contain all resources that were reset, those resources cannot be restored later. The entire reset/restore cycle adds complexity and leaving resources in the reset state causes issues to other code such as for checks done in pci_enable_resources(). Take a small step towards not resetting resources by delaying reset until the end of resource assignment and build failure list (fail_head) in sync with the reset to avoid leaving behind resources that cannot be restored (for the case where the caller provides fail_head in the first place to allow restore somewhere in the callchain, as is not all callers pass non-NULL fail_head). Leave the Expansion ROM check temporarily in place while building the failure list until an upcoming change that reworks optional resource handling. Ideally, whole resource reset could be removed but doing that in one step would be non-tractable due to complexity of all related code. Link: https://lore.kernel.org/r/20241216175632.4175-25-ilpo.jarvinen@linux.intel.com Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Tested-by: Xiaochun Lee --- drivers/pci/setup-bus.c | 35 +++++++++++++++++++++++++++++------ 1 file changed, 29 insertions(+), 6 deletions(-) diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index ef1c82d2e58e..b0b146757943 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -252,9 +252,14 @@ static void reassign_resources_sorted(struct list_head *realloc_head, res = add_res->res; dev = add_res->dev; + idx = pci_resource_num(dev, res); - /* Skip resource that has been reset */ - if (!res->flags) + /* + * Skip resource that failed the earlier assignment and is + * not optional as it would just fail again. + */ + if (!res->parent && resource_size(res) && + !pci_resource_is_optional(dev, idx)) goto out; /* Skip this resource if not found in head list */ @@ -267,7 +272,6 @@ static void reassign_resources_sorted(struct list_head *realloc_head, if (!found_match) /* Just skip */ continue; - idx = pci_resource_num(dev, res); res_name = pci_resource_name(dev, idx); add_size = add_res->add_size; align = add_res->min_align; @@ -277,7 +281,6 @@ static void reassign_resources_sorted(struct list_head *realloc_head, pci_dbg(dev, "%s %pR: ignoring failure in optional allocation\n", res_name, res); - reset_resource(res); } } else { res->flags |= add_res->flags & @@ -332,7 +335,6 @@ static void assign_requested_resources_sorted(struct list_head *head, 0 /* don't care */, 0 /* don't care */); } - reset_resource(res); } } } @@ -518,13 +520,34 @@ static void __assign_resources_sorted(struct list_head *head, requested_and_reassign: /* Satisfy the must-have resource requests */ - assign_requested_resources_sorted(head, fail_head); + assign_requested_resources_sorted(head, NULL); /* Try to satisfy any additional optional resource requests */ if (!list_empty(realloc_head)) reassign_resources_sorted(realloc_head, head); out: + /* Reset any failed resource, cannot use fail_head as it can be NULL. */ + list_for_each_entry(dev_res, head, list) { + res = dev_res->res; + dev = dev_res->dev; + + if (res->parent) + continue; + + /* + * If the failed resource is a ROM BAR and it will + * be enabled later, don't add it to the list. + */ + if (fail_head && !pci_resource_is_disabled_rom(res, idx)) { + add_to_list(fail_head, dev, res, + 0 /* don't care */, + 0 /* don't care */); + } + + reset_resource(res); + } + free_list(head); }