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linux-next/include/linux/enclosure.h
Gustavo A. R. Silva 192199464d enclosure.h: Replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
2020-04-18 15:44:54 -05:00

136 lines
4.0 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Enclosure Services
*
* Copyright (C) 2008 James Bottomley <James.Bottomley@HansenPartnership.com>
*
**-----------------------------------------------------------------------------
**
**
**-----------------------------------------------------------------------------
*/
#ifndef _LINUX_ENCLOSURE_H_
#define _LINUX_ENCLOSURE_H_
#include <linux/device.h>
#include <linux/list.h>
/* A few generic types ... taken from ses-2 */
enum enclosure_component_type {
ENCLOSURE_COMPONENT_DEVICE = 0x01,
ENCLOSURE_COMPONENT_CONTROLLER_ELECTRONICS = 0x07,
ENCLOSURE_COMPONENT_SCSI_TARGET_PORT = 0x14,
ENCLOSURE_COMPONENT_SCSI_INITIATOR_PORT = 0x15,
ENCLOSURE_COMPONENT_ARRAY_DEVICE = 0x17,
ENCLOSURE_COMPONENT_SAS_EXPANDER = 0x18,
};
/* ses-2 common element status */
enum enclosure_status {
ENCLOSURE_STATUS_UNSUPPORTED = 0,
ENCLOSURE_STATUS_OK,
ENCLOSURE_STATUS_CRITICAL,
ENCLOSURE_STATUS_NON_CRITICAL,
ENCLOSURE_STATUS_UNRECOVERABLE,
ENCLOSURE_STATUS_NOT_INSTALLED,
ENCLOSURE_STATUS_UNKNOWN,
ENCLOSURE_STATUS_UNAVAILABLE,
/* last element for counting purposes */
ENCLOSURE_STATUS_MAX
};
/* SFF-8485 activity light settings */
enum enclosure_component_setting {
ENCLOSURE_SETTING_DISABLED = 0,
ENCLOSURE_SETTING_ENABLED = 1,
ENCLOSURE_SETTING_BLINK_A_ON_OFF = 2,
ENCLOSURE_SETTING_BLINK_A_OFF_ON = 3,
ENCLOSURE_SETTING_BLINK_B_ON_OFF = 6,
ENCLOSURE_SETTING_BLINK_B_OFF_ON = 7,
};
struct enclosure_device;
struct enclosure_component;
struct enclosure_component_callbacks {
void (*get_status)(struct enclosure_device *,
struct enclosure_component *);
int (*set_status)(struct enclosure_device *,
struct enclosure_component *,
enum enclosure_status);
void (*get_fault)(struct enclosure_device *,
struct enclosure_component *);
int (*set_fault)(struct enclosure_device *,
struct enclosure_component *,
enum enclosure_component_setting);
void (*get_active)(struct enclosure_device *,
struct enclosure_component *);
int (*set_active)(struct enclosure_device *,
struct enclosure_component *,
enum enclosure_component_setting);
void (*get_locate)(struct enclosure_device *,
struct enclosure_component *);
int (*set_locate)(struct enclosure_device *,
struct enclosure_component *,
enum enclosure_component_setting);
void (*get_power_status)(struct enclosure_device *,
struct enclosure_component *);
int (*set_power_status)(struct enclosure_device *,
struct enclosure_component *,
int);
int (*show_id)(struct enclosure_device *, char *buf);
};
struct enclosure_component {
void *scratch;
struct device cdev;
struct device *dev;
enum enclosure_component_type type;
int number;
int fault;
int active;
int locate;
int slot;
enum enclosure_status status;
int power_status;
};
struct enclosure_device {
void *scratch;
struct list_head node;
struct device edev;
struct enclosure_component_callbacks *cb;
int components;
struct enclosure_component component[];
};
static inline struct enclosure_device *
to_enclosure_device(struct device *dev)
{
return container_of(dev, struct enclosure_device, edev);
}
static inline struct enclosure_component *
to_enclosure_component(struct device *dev)
{
return container_of(dev, struct enclosure_component, cdev);
}
struct enclosure_device *
enclosure_register(struct device *, const char *, int,
struct enclosure_component_callbacks *);
void enclosure_unregister(struct enclosure_device *);
struct enclosure_component *
enclosure_component_alloc(struct enclosure_device *, unsigned int,
enum enclosure_component_type, const char *);
int enclosure_component_register(struct enclosure_component *);
int enclosure_add_device(struct enclosure_device *enclosure, int component,
struct device *dev);
int enclosure_remove_device(struct enclosure_device *, struct device *);
struct enclosure_device *enclosure_find(struct device *dev,
struct enclosure_device *start);
int enclosure_for_each_device(int (*fn)(struct enclosure_device *, void *),
void *data);
#endif /* _LINUX_ENCLOSURE_H_ */