![Lukas Wunner](/assets/img/avatar_default.png)
When the PCI hotplug core and its first user, cpqphp, were introduced in February 2002 with historic commit a8a2069f432c, cpqphp allocated a slot struct for its internal use plus a hotplug_slot struct to be registered with the hotplug core and linked the two with pointers: https://git.kernel.org/tglx/history/c/a8a2069f432c Nowadays, the predominant pattern in the tree is to embed ("subclass") such structures in one another and cast to the containing struct with container_of(). But it wasn't until July 2002 that container_of() was introduced with historic commit ec4f214232cf: https://git.kernel.org/tglx/history/c/ec4f214232cf pnv_php, introduced in 2016, did the right thing and embedded struct hotplug_slot in its internal struct pnv_php_slot, but all other drivers cargo-culted cpqphp's design and linked separate structs with pointers. Embedding structs is preferrable to linking them with pointers because it requires fewer allocations, thereby reducing overhead and simplifying error paths. Casting an embedded struct to the containing struct becomes a cheap subtraction rather than a dereference. And having fewer pointers reduces the risk of them pointing nowhere either accidentally or due to an attack. Convert all drivers to embed struct hotplug_slot in their internal slot struct. The "private" pointer in struct hotplug_slot thereby becomes unused, so drop it. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com> # drivers/pci/hotplug/rpa* Acked-by: Sebastian Ott <sebott@linux.ibm.com> # drivers/pci/hotplug/s390* Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> # drivers/platform/x86 Cc: Len Brown <lenb@kernel.org> Cc: Scott Murray <scott@spiteful.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Oliver OHalloran <oliveroh@au1.ibm.com> Cc: Gavin Shan <gwshan@linux.vnet.ibm.com> Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com> Cc: Corentin Chary <corentin.chary@gmail.com> Cc: Darren Hart <dvhart@infradead.org>
102 lines
2.6 KiB
C
102 lines
2.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* CompactPCI Hot Plug Core Functions
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*
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* Copyright (C) 2002 SOMA Networks, Inc.
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* Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
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* Copyright (C) 2001 IBM Corp.
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*
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* All rights reserved.
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*
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* Send feedback to <scottm@somanetworks.com>
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*/
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#ifndef _CPCI_HOTPLUG_H
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#define _CPCI_HOTPLUG_H
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#include <linux/types.h>
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#include <linux/pci.h>
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#include <linux/pci_hotplug.h>
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/* PICMG 2.1 R2.0 HS CSR bits: */
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#define HS_CSR_INS 0x0080
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#define HS_CSR_EXT 0x0040
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#define HS_CSR_PI 0x0030
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#define HS_CSR_LOO 0x0008
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#define HS_CSR_PIE 0x0004
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#define HS_CSR_EIM 0x0002
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#define HS_CSR_DHA 0x0001
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struct slot {
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u8 number;
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unsigned int devfn;
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struct pci_bus *bus;
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struct pci_dev *dev;
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unsigned int latch_status:1;
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unsigned int adapter_status:1;
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unsigned int extracting;
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struct hotplug_slot hotplug_slot;
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struct list_head slot_list;
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};
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struct cpci_hp_controller_ops {
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int (*query_enum)(void);
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int (*enable_irq)(void);
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int (*disable_irq)(void);
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int (*check_irq)(void *dev_id);
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int (*hardware_test)(struct slot *slot, u32 value);
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u8 (*get_power)(struct slot *slot);
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int (*set_power)(struct slot *slot, int value);
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};
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struct cpci_hp_controller {
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unsigned int irq;
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unsigned long irq_flags;
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char *devname;
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void *dev_id;
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char *name;
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struct cpci_hp_controller_ops *ops;
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};
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static inline const char *slot_name(struct slot *slot)
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{
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return hotplug_slot_name(&slot->hotplug_slot);
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}
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static inline struct slot *to_slot(struct hotplug_slot *hotplug_slot)
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{
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return container_of(hotplug_slot, struct slot, hotplug_slot);
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}
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int cpci_hp_register_controller(struct cpci_hp_controller *controller);
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int cpci_hp_unregister_controller(struct cpci_hp_controller *controller);
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int cpci_hp_register_bus(struct pci_bus *bus, u8 first, u8 last);
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int cpci_hp_unregister_bus(struct pci_bus *bus);
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int cpci_hp_start(void);
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int cpci_hp_stop(void);
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/*
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* Internal function prototypes, these functions should not be used by
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* board/chassis drivers.
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*/
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u8 cpci_get_attention_status(struct slot *slot);
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u8 cpci_get_latch_status(struct slot *slot);
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u8 cpci_get_adapter_status(struct slot *slot);
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u16 cpci_get_hs_csr(struct slot *slot);
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int cpci_set_attention_status(struct slot *slot, int status);
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int cpci_check_and_clear_ins(struct slot *slot);
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int cpci_check_ext(struct slot *slot);
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int cpci_clear_ext(struct slot *slot);
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int cpci_led_on(struct slot *slot);
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int cpci_led_off(struct slot *slot);
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int cpci_configure_slot(struct slot *slot);
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int cpci_unconfigure_slot(struct slot *slot);
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#ifdef CONFIG_HOTPLUG_PCI_CPCI
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int cpci_hotplug_init(int debug);
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#else
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static inline int cpci_hotplug_init(int debug) { return 0; }
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#endif
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#endif /* _CPCI_HOTPLUG_H */
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