/*
* Find an unused file structure and return a pointer to it.
* Returns NULL, if there are no more free file structures or
* we run out of memory.
*/
struct file * get_empty_filp(void)
{
int i;
int max = max_files;
struct file * f;
/*
* Reserve a few files for the super-user..
*/
if (current->euid)
max -= 10;
/* if the return is taken, we are in deep trouble */
if (!first_file && !grow_files())
return NULL;
do {
for (f = first_file, i=0; i < nr_files; i++, f = f->f_next)
if (!f->f_count) {
remove_file_free(f);
memset(f,0,sizeof(*f));
put_last_free(f);
f->f_count = 1;
f->f_version = ++event;
return f;
}
} while (nr_files < max && grow_files());
return NULL;
}
static void put_last_free(struct file *file)
{
remove_file_free(file);
file->f_prev = first_file->f_prev;
file->f_prev->f_next = file;
file->f_next = first_file;
file->f_next->f_prev = file;
}
struct file * get_empty_filp(void)
{
int i;
struct file * f;
if (!first_file)
grow_files();
repeat:
for (f = first_file, i=0; i < nr_files; i++, f = f->f_next)
if (!f->f_count) {
remove_file_free(f);
memset(f,0,sizeof(*f));
put_last_free(f);
f->f_count = 1;
return f;
}
if (nr_files < NR_FILE) {
grow_files();
goto repeat;
}
return NULL;
}
