From: Farhan Ali <[email protected]> [ Upstream commit c243e6c470c4695965cc8287767925bc1d9a7867 ]
Introduce a constant for placeholder value and update the kerneldoc for pci_create_slot() to reference PCI_SLOT_PLACEHOLDER instead of -1 throughout. No functional change. Suggested-by: Bjorn Helgaas <[email protected]> Signed-off-by: Farhan Ali <[email protected]> Signed-off-by: Bjorn Helgaas <[email protected]> Cc: Madhavan Srinivasan <[email protected]> Cc: Tyrel Datwyler <[email protected]> Cc: [email protected] Link: https://patch.msgid.link/[email protected] Stable backport: this tree predates 102c8b26b54e ("PCI: Allow all bus devices to use the same slot"). Include its PCI_SLOT_ALL_DEVICES definition, slot-number documentation, and core matching/address handling so that subsequent commit dcc5bec09e23 ("PCI: Allow per function PCI slots to fix slot reset on s390") applies without conflicts. Keep the PCIe hotplug callers unchanged; enabling bus-wide slots there is outside this dependency. Retain the stable tree's kzalloc() and ATTRIBUTE_GROUPS() implementations. The placeholder conversion covers both PowerPC hotplug callers and the PCI core. All code changes stay within existing functions. Stable-dep-of: dcc5bec09e23 ("PCI: Allow per function PCI slots to fix slot reset on s390") Signed-off-by: Sasha Levin <[email protected]> --- drivers/pci/hotplug/pnv_php.c | 2 +- drivers/pci/hotplug/rpaphp_slot.c | 2 +- drivers/pci/slot.c | 50 +++++++++++++++++++++++-------- include/linux/pci.h | 13 +++++++- 4 files changed, 51 insertions(+), 16 deletions(-) diff --git a/drivers/pci/hotplug/pnv_php.c b/drivers/pci/hotplug/pnv_php.c index ec7828ad66617..2bd2b7599d1c4 100644 --- a/drivers/pci/hotplug/pnv_php.c +++ b/drivers/pci/hotplug/pnv_php.c @@ -799,7 +799,7 @@ static struct pnv_php_slot *pnv_php_alloc_slot(struct device_node *dn) if (dn->child && PCI_DN(dn->child)) php_slot->slot_no = PCI_SLOT(PCI_DN(dn->child)->devfn); else - php_slot->slot_no = -1; /* Placeholder slot */ + php_slot->slot_no = PCI_SLOT_PLACEHOLDER; /* Placeholder slot */ kref_init(&php_slot->kref); php_slot->state = PNV_PHP_STATE_INITIALIZED; diff --git a/drivers/pci/hotplug/rpaphp_slot.c b/drivers/pci/hotplug/rpaphp_slot.c index 779eab12e9810..ac8c512190df4 100644 --- a/drivers/pci/hotplug/rpaphp_slot.c +++ b/drivers/pci/hotplug/rpaphp_slot.c @@ -85,7 +85,7 @@ int rpaphp_register_slot(struct slot *slot) struct device_node *child; u32 my_index; int retval; - int slotno = -1; + int slotno = PCI_SLOT_PLACEHOLDER; dbg("%s registering slot:path[%pOF] index[%x], name[%s] pdomain[%x] type[%d]\n", __func__, slot->dn, slot->index, slot->name, diff --git a/drivers/pci/slot.c b/drivers/pci/slot.c index 7f4bcf359b917..82a37a4973f9a 100644 --- a/drivers/pci/slot.c +++ b/drivers/pci/slot.c @@ -38,11 +38,20 @@ static const struct sysfs_ops pci_slot_sysfs_ops = { static ssize_t address_read_file(struct pci_slot *slot, char *buf) { - if (slot->number == 0xff) + if (slot->number == PCI_SLOT_PLACEHOLDER) return sysfs_emit(buf, "%04x:%02x\n", pci_domain_nr(slot->bus), slot->bus->number); + /* + * Preserve legacy ABI expectations that hotplug drivers that manage + * multiple devices per slot emit 0 for the device number. + */ + if (slot->number == PCI_SLOT_ALL_DEVICES) + return sysfs_emit(buf, "%04x:%02x:00\n", + pci_domain_nr(slot->bus), + slot->bus->number); + return sysfs_emit(buf, "%04x:%02x:%02x\n", pci_domain_nr(slot->bus), slot->bus->number, @@ -74,7 +83,8 @@ static void pci_slot_release(struct kobject *kobj) down_read(&pci_bus_sem); list_for_each_entry(dev, &slot->bus->devices, bus_list) - if (PCI_SLOT(dev->devfn) == slot->number) + if (slot->number == PCI_SLOT_ALL_DEVICES || + PCI_SLOT(dev->devfn) == slot->number) dev->slot = NULL; up_read(&pci_bus_sem); @@ -167,7 +177,8 @@ void pci_dev_assign_slot(struct pci_dev *dev) mutex_lock(&pci_slot_mutex); list_for_each_entry(slot, &dev->bus->slots, list) - if (PCI_SLOT(dev->devfn) == slot->number) + if (slot->number == PCI_SLOT_ALL_DEVICES || + PCI_SLOT(dev->devfn) == slot->number) dev->slot = slot; mutex_unlock(&pci_slot_mutex); } @@ -189,7 +200,8 @@ static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr) /** * pci_create_slot - create or increment refcount for physical PCI slot * @parent: struct pci_bus of parent bridge - * @slot_nr: PCI_SLOT(pci_dev->devfn) or -1 for placeholder + * @slot_nr: PCI_SLOT(pci_dev->devfn), PCI_SLOT_PLACEHOLDER for placeholder, or + * PCI_SLOT_ALL_DEVICES * @name: user visible string presented in /sys/bus/pci/slots/<name> * @hotplug: set if caller is hotplug driver, NULL otherwise * @@ -214,15 +226,26 @@ static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr) * In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify * a slot. There is one notable exception - pSeries (rpaphp), where the * @slot_nr cannot be determined until a device is actually inserted into - * the slot. In this scenario, the caller may pass -1 for @slot_nr. + * the slot. In this scenario, the caller may pass PCI_SLOT_PLACEHOLDER for @slot_nr. * * The following semantics are imposed when the caller passes @slot_nr == - * -1. First, we no longer check for an existing %struct pci_slot, as there - * may be many slots with @slot_nr of -1. The other change in semantics is - * user-visible, which is the 'address' parameter presented in sysfs will - * consist solely of a dddd:bb tuple, where dddd is the PCI domain of the - * %struct pci_bus and bb is the bus number. In other words, the devfn of - * the 'placeholder' slot will not be displayed. + * PCI_SLOT_PLACEHOLDER. First, we no longer check for an existing %struct + * pci_slot, as there may be many slots with @slot_nr of + * PCI_SLOT_PLACEHOLDER. The other change in semantics is user-visible, + * which is the 'address' parameter presented in sysfs will consist solely + * of a dddd:bb tuple, where dddd is the PCI domain of the %struct pci_bus + * and bb is the bus number. In other words, the devfn of the 'placeholder' + * slot will not be displayed. + * + * Bus-wide slots: + * For PCIe hotplug, the physical slot encompasses the entire secondary + * bus, not just a single device number. If the device supports ARI and ARI + * Forwarding is enabled in the upstream bridge, a multi-function device + * may include functions that appear to have several different device + * numbers, i.e., PCI_SLOT() values. Pass @slot_nr == PCI_SLOT_ALL_DEVICES + * to create a slot that matches all devices on the bus. Unlike placeholder + * slots, bus-wide slots go through normal slot lookup and reuse existing + * slots if present. */ struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr, const char *name, @@ -235,7 +258,7 @@ struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr, mutex_lock(&pci_slot_mutex); - if (slot_nr == -1) + if (slot_nr == PCI_SLOT_PLACEHOLDER) goto placeholder; /* @@ -287,7 +310,8 @@ struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr, down_read(&pci_bus_sem); list_for_each_entry(dev, &parent->devices, bus_list) - if (PCI_SLOT(dev->devfn) == slot_nr) + if (slot_nr == PCI_SLOT_ALL_DEVICES || + PCI_SLOT(dev->devfn) == slot_nr) dev->slot = slot; up_read(&pci_bus_sem); diff --git a/include/linux/pci.h b/include/linux/pci.h index 282e86b9a35fe..8babaffbe8b11 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -71,12 +71,23 @@ /* return bus from PCI devid = ((u16)bus_number) << 8) | devfn */ #define PCI_BUS_NUM(x) (((x) >> 8) & 0xff) +/* + * PCI_SLOT_ALL_DEVICES indicates a slot that covers all devices on the bus. + * Used for PCIe hotplug where the physical slot is the entire secondary bus, + * and, if ARI Forwarding is enabled, functions may appear to be on multiple + * devices. + */ +#define PCI_SLOT_ALL_DEVICES 0xfe + +/* Used to identify a slot as a placeholder */ +#define PCI_SLOT_PLACEHOLDER 0xff + /* pci_slot represents a physical slot */ struct pci_slot { struct pci_bus *bus; /* Bus this slot is on */ struct list_head list; /* Node in list of slots */ struct hotplug_slot *hotplug; /* Hotplug info (move here) */ - unsigned char number; /* PCI_SLOT(pci_dev->devfn) */ + unsigned char number; /* Device nr, or PCI_SLOT_ALL_DEVICES */ struct kobject kobj; }; -- 2.53.0
