From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F23785172EF; Wed, 30 Sep 2026 17:35:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790789742; cv=none; b=UHIKYgW8f5FFzGAwS/aDmcj8U8zgQc9Ojz4V8oAb0sx2qA2Mu+jPvEOcUsOom5+4WzRNeZjB0VZhWKjXKAaA1xn0xBfsl8ppNp077VXi9fBdTT/76uzSdcnBP5t7mSI6pCd5RA0MA4VYDA5d7RNJ1O7NPp96qqcA7K8hYN9pQfo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790789742; c=relaxed/simple; bh=gSYjg7ta3FDddXKoSoOyRyFcjpVTKUPymKiWjEyamHc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FO2ot6/pVrfOqgk4nTKesJz+V7OAvPrC6v5eunVvPYT8hhgKsbDUyNxywyEd3633pckiLSW2tRP0/u65knuWR8WIhvJ6wIuDcntFtfDqZZxPmEBaWeciSh/pIsFWlmVj4sxuNO/Ora4dwkzw6VlaBjvgf5Dtk3baXusuZDukcs4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hgagfk3j; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="hgagfk3j" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4D4C11F0089A; Wed, 30 Sep 2026 17:35:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790789740; bh=abrwkof5q9mTnOuGs1JN3KkyOxz8hNAB+0DBPFbl00k=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=hgagfk3j/V34sntu3NnWLI8de2Ti/M30dW8GMFO+dMLglpcFm6R9bUfhFhoHWQLrR f5dgGR5zDsPKjg/bn3EdnQfPBonOQQPeWbPTVmIwfT93KmNU0F9OPZIRgSZ1ndIuok 0jlvgf1fdIcati6A8aVjb7NMjWTlItm7wSRKZjkc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Bjorn Helgaas , Farhan Ali , Madhavan Srinivasan , Tyrel Datwyler , linuxppc-dev@lists.ozlabs.org, Sasha Levin Subject: [PATCH 6.12 582/877] PCI: Introduce PCI_SLOT_PLACEHOLDER constant for slot_nr placeholder value Date: Wed, 30 Sep 2026 17:24:53 +0200 Message-ID: <20260930152427.203723901@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152414.738996857@linuxfoundation.org> References: <20260930152414.738996857@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Farhan Ali [ 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 Signed-off-by: Farhan Ali Signed-off-by: Bjorn Helgaas Cc: Madhavan Srinivasan Cc: Tyrel Datwyler Cc: linuxppc-dev@lists.ozlabs.org Link: https://patch.msgid.link/20260805165518.794-2-alifm@linux.ibm.com 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 Signed-off-by: Greg Kroah-Hartman --- 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(-) --- a/drivers/pci/hotplug/pnv_php.c +++ b/drivers/pci/hotplug/pnv_php.c @@ -800,7 +800,7 @@ static struct pnv_php_slot *pnv_php_allo 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; --- a/drivers/pci/hotplug/rpaphp_slot.c +++ b/drivers/pci/hotplug/rpaphp_slot.c @@ -85,7 +85,7 @@ int rpaphp_register_slot(struct slot *sl 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, --- a/drivers/pci/slot.c +++ b/drivers/pci/slot.c @@ -38,11 +38,20 @@ static const struct sysfs_ops pci_slot_s 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 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 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_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/ * @hotplug: set if caller is hotplug driver, NULL otherwise * @@ -214,15 +226,26 @@ static struct pci_slot *get_slot(struct * 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 mutex_lock(&pci_slot_mutex); - if (slot_nr == -1) + if (slot_nr == PCI_SLOT_PLACEHOLDER) goto placeholder; /* @@ -287,7 +310,8 @@ placeholder: 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); --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -72,12 +72,23 @@ /* 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; };