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#define S_SIZE (1024 - (sizeof(unsigned int) + 1))
struct sbuff {
unsigned int count;
char buf[S_SIZE + 1];
};
static struct sbuff emergency, *emergency_ptr = &emergency;
static __printf(2, 3) int sb_add(struct sbuff *m, const char *f, ...)
{
va_list args;
int len;
if (likely(m->count < S_SIZE)) {
va_start(args, f);
len = vsnprintf(m->buf + m->count, S_SIZE - m->count, f, args);
va_end(args);
if (likely(m->count + len < S_SIZE)) {
m->count += len;
return 0;
}
}
m->count = S_SIZE;
printk_once(KERN_ERR KBUILD_MODNAME " please increase S_SIZE\n");
return -1;
}
static struct sbuff *sb_open(void)
{
struct sbuff *m = kmalloc(sizeof(*m), GFP_ATOMIC);
if (unlikely(!m)) {
local_bh_disable();
do {
m = xchg(&emergency_ptr, NULL);
} while (!m);
}
m->count = 0;
return m;
}
static void sb_close(struct sbuff *m)
{
m->buf[m->count] = 0;
printk("%s\n", m->buf);
if (likely(m != &emergency))
kfree(m);
else {
emergency_ptr = m;
local_bh_enable();
}
}
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