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9ec6dbfbdc
When calling debugfs functions, there is no need to ever check the return value. The function can work or not, but the code logic should never do something different based on this. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
94 lines
2.0 KiB
C
94 lines
2.0 KiB
C
/*
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* custom_method.c - debugfs interface for customizing ACPI control method
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/uaccess.h>
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#include <linux/debugfs.h>
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#include <linux/acpi.h>
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#include "internal.h"
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#define _COMPONENT ACPI_SYSTEM_COMPONENT
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ACPI_MODULE_NAME("custom_method");
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MODULE_LICENSE("GPL");
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static struct dentry *cm_dentry;
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/* /sys/kernel/debug/acpi/custom_method */
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static ssize_t cm_write(struct file *file, const char __user * user_buf,
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size_t count, loff_t *ppos)
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{
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static char *buf;
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static u32 max_size;
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static u32 uncopied_bytes;
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struct acpi_table_header table;
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acpi_status status;
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if (!(*ppos)) {
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/* parse the table header to get the table length */
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if (count <= sizeof(struct acpi_table_header))
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return -EINVAL;
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if (copy_from_user(&table, user_buf,
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sizeof(struct acpi_table_header)))
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return -EFAULT;
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uncopied_bytes = max_size = table.length;
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buf = kzalloc(max_size, GFP_KERNEL);
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if (!buf)
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return -ENOMEM;
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}
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if (buf == NULL)
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return -EINVAL;
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if ((*ppos > max_size) ||
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(*ppos + count > max_size) ||
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(*ppos + count < count) ||
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(count > uncopied_bytes))
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return -EINVAL;
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if (copy_from_user(buf + (*ppos), user_buf, count)) {
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kfree(buf);
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buf = NULL;
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return -EFAULT;
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}
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uncopied_bytes -= count;
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*ppos += count;
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if (!uncopied_bytes) {
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status = acpi_install_method(buf);
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kfree(buf);
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buf = NULL;
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if (ACPI_FAILURE(status))
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return -EINVAL;
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add_taint(TAINT_OVERRIDDEN_ACPI_TABLE, LOCKDEP_NOW_UNRELIABLE);
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}
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return count;
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}
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static const struct file_operations cm_fops = {
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.write = cm_write,
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.llseek = default_llseek,
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};
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static int __init acpi_custom_method_init(void)
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{
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cm_dentry = debugfs_create_file("custom_method", S_IWUSR,
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acpi_debugfs_dir, NULL, &cm_fops);
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return 0;
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}
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static void __exit acpi_custom_method_exit(void)
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{
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debugfs_remove(cm_dentry);
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}
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module_init(acpi_custom_method_init);
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module_exit(acpi_custom_method_exit);
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