From patchwork Thu Mar 10 18:11:45 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. 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Violators will be prosecuted; Thu, 10 Mar 2016 15:12:11 -0300 X-IBM-Helo: d24dlp01.br.ibm.com X-IBM-MailFrom: gpiccoli@linux.vnet.ibm.com X-IBM-RcptTo: linuxppc-dev@lists.ozlabs.org Received: from d24relay03.br.ibm.com (d24relay03.br.ibm.com [9.13.184.25]) by d24dlp01.br.ibm.com (Postfix) with ESMTP id AAB2F3520077 for ; Thu, 10 Mar 2016 13:12:00 -0500 (EST) Received: from d24av05.br.ibm.com (d24av05.br.ibm.com [9.18.232.44]) by d24relay03.br.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u2AHBfGJ5112202 for ; Thu, 10 Mar 2016 14:11:41 -0300 Received: from d24av05.br.ibm.com (localhost [127.0.0.1]) by d24av05.br.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u2AIC90l029550 for ; Thu, 10 Mar 2016 13:12:09 -0500 Received: from localhost (HarryBosch.br.ibm.com [9.18.235.42]) by d24av05.br.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id u2AIC9n3029544; Thu, 10 Mar 2016 13:12:09 -0500 From: "Guilherme G. Piccoli" To: linuxppc-dev@lists.ozlabs.org Subject: [PATCH] powerpc/pci: Reuse PHB number on pci_controller add if available Date: Thu, 10 Mar 2016 15:11:45 -0300 Message-Id: <1457633505-19857-2-git-send-email-gpiccoli@linux.vnet.ibm.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1457633505-19857-1-git-send-email-gpiccoli@linux.vnet.ibm.com> References: <1457633505-19857-1-git-send-email-gpiccoli@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16031018-0021-0000-0000-0000054707AE X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mikey@neuling.org, gpiccoli@linux.vnet.ibm.com, linux-pci@vger.kernel.org, gwshan@linux.vnet.ibm.com, paulus@samba.org, imunsie@au1.ibm.com, andrew.donnellan@au1.ibm.com, bhelgaas@google.com MIME-Version: 1.0 Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" The domain/PHB field of PCI addresses has its value obtained from a global variable, incremented each time a new domain (represented by struct pci_controller) is added on the system. The domain addition process happens during boot or due to PCI device hotplug. As recent kernels are using predictable naming for network interfaces, the network stack is more tied to PCI naming. This can be a problem in hotplug scenarios, because PCI addresses will change if a device is removed and then re-added. This situation seems unusual, but it can happen if a user wants to replace a NIC without rebooting the machine, for example. This patch changes the way PCI domain values are generated: the global variable is no longer used; instead, a list is introduced, containing a flag that indicates whenever a domain is in use or was released, for example by a PCI hotplug remove. If the new PHB being added finds a free domain, it will use its number; otherwise a new number is generated incrementing the higher domain value present on the system. No functional changes were introduced. Signed-off-by: Guilherme G. Piccoli --- arch/powerpc/kernel/pci-common.c | 47 +++++++++++++++++++++++++++++++++++++--- 1 file changed, 44 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c index 0f7a60f..6eac0dd 100644 --- a/arch/powerpc/kernel/pci-common.c +++ b/arch/powerpc/kernel/pci-common.c @@ -44,8 +44,12 @@ static DEFINE_SPINLOCK(hose_spinlock); LIST_HEAD(hose_list); -/* XXX kill that some day ... */ -static int global_phb_number; /* Global phb counter */ +/* Global PHB counter list */ +struct global_phb_number { + bool used; + struct list_head node; +}; +LIST_HEAD(global_phb_number_list); /* ISA Memory physical address */ resource_size_t isa_mem_base; @@ -64,6 +68,42 @@ struct dma_map_ops *get_pci_dma_ops(void) } EXPORT_SYMBOL(get_pci_dma_ops); +static int get_phb_number(void) +{ + struct global_phb_number *ptr; + int latest_number = 0; + + list_for_each_entry(ptr, &global_phb_number_list, node) { + if (!ptr->used) { + ptr->used = true; + return latest_number; + } + latest_number++; + } + + ptr = zalloc_maybe_bootmem(sizeof(struct global_phb_number), GFP_KERNEL); + BUG_ON(ptr == NULL); + + ptr->used = true; + list_add_tail(&ptr->node, &global_phb_number_list); + + return latest_number; +} + +static void release_phb_number(int phb_number) +{ + struct global_phb_number *ptr; + int current_number = 0; + + list_for_each_entry(ptr, &global_phb_number_list, node) { + if (current_number == phb_number) { + ptr->used = false; + return; + } + current_number++; + } +} + struct pci_controller *pcibios_alloc_controller(struct device_node *dev) { struct pci_controller *phb; @@ -72,7 +112,7 @@ struct pci_controller *pcibios_alloc_controller(struct device_node *dev) if (phb == NULL) return NULL; spin_lock(&hose_spinlock); - phb->global_number = global_phb_number++; + phb->global_number = get_phb_number(); list_add_tail(&phb->list_node, &hose_list); spin_unlock(&hose_spinlock); phb->dn = dev; @@ -94,6 +134,7 @@ EXPORT_SYMBOL_GPL(pcibios_alloc_controller); void pcibios_free_controller(struct pci_controller *phb) { spin_lock(&hose_spinlock); + release_phb_number(phb->global_number); list_del(&phb->list_node); spin_unlock(&hose_spinlock);