精通linux设备驱动开发 笔记

#include <linux/err.h>

char *
collect_data(char *userbuffer)
{

  char *buffer;

  /* ... */
  buffer = kmalloc(100, GFP_KERNEL);
  if (!buffer) { /* Out of memory */
    return ERR_PTR(-ENOMEM);
  }

  /* ... */
  if (copy_from_user(buffer, userbuffer, 100)) {
    return ERR_PTR(-EFAULT);
  }
  /* ... */

  return(buffer);
}

int
my_function(char *userbuffer)
{
  char *buf;

  /* ... */
  buf = collect_data(userbuffer);
  if (IS_ERR(buf)) {
    printk("Error returned is %d!\n", PTR_ERR(buf));
  }
  /* ... */

}