cpumask: convert kernel/compat.c
Rusty Russell [Wed, 31 Dec 2008 23:42:24 +0000 (09:42 +1030)]
Impact: Reduce stack usage, use new cpumask API.

Straightforward conversion; cpumasks' size is given by cpumask_size() (now
a variable rather than fixed) and on-stack cpu masks use cpumask_var_t.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

kernel/compat.c

index 8eafe3e..d52e2ec 100644 (file)
@@ -454,16 +454,16 @@ asmlinkage long compat_sys_waitid(int which, compat_pid_t pid,
 }
 
 static int compat_get_user_cpu_mask(compat_ulong_t __user *user_mask_ptr,
-                                   unsigned len, cpumask_t *new_mask)
+                                   unsigned len, struct cpumask *new_mask)
 {
        unsigned long *k;
 
-       if (len < sizeof(cpumask_t))
-               memset(new_mask, 0, sizeof(cpumask_t));
-       else if (len > sizeof(cpumask_t))
-               len = sizeof(cpumask_t);
+       if (len < cpumask_size())
+               memset(new_mask, 0, cpumask_size());
+       else if (len > cpumask_size())
+               len = cpumask_size();
 
-       k = cpus_addr(*new_mask);
+       k = cpumask_bits(new_mask);
        return compat_get_bitmap(k, user_mask_ptr, len * 8);
 }
 
@@ -471,40 +471,51 @@ asmlinkage long compat_sys_sched_setaffinity(compat_pid_t pid,
                                             unsigned int len,
                                             compat_ulong_t __user *user_mask_ptr)
 {
-       cpumask_t new_mask;
+       cpumask_var_t new_mask;
        int retval;
 
-       retval = compat_get_user_cpu_mask(user_mask_ptr, len, &new_mask);
+       if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
+               return -ENOMEM;
+
+       retval = compat_get_user_cpu_mask(user_mask_ptr, len, new_mask);
        if (retval)
-               return retval;
+               goto out;
 
-       return sched_setaffinity(pid, &new_mask);
+       retval = sched_setaffinity(pid, new_mask);
+out:
+       free_cpumask_var(new_mask);
+       return retval;
 }
 
 asmlinkage long compat_sys_sched_getaffinity(compat_pid_t pid, unsigned int len,
                                             compat_ulong_t __user *user_mask_ptr)
 {
        int ret;
-       cpumask_t mask;
+       cpumask_var_t mask;
        unsigned long *k;
-       unsigned int min_length = sizeof(cpumask_t);
+       unsigned int min_length = cpumask_size();
 
-       if (NR_CPUS <= BITS_PER_COMPAT_LONG)
+       if (nr_cpu_ids <= BITS_PER_COMPAT_LONG)
                min_length = sizeof(compat_ulong_t);
 
        if (len < min_length)
                return -EINVAL;
 
-       ret = sched_getaffinity(pid, &mask);
+       if (!alloc_cpumask_var(&mask, GFP_KERNEL))
+               return -ENOMEM;
+
+       ret = sched_getaffinity(pid, mask);
        if (ret < 0)
-               return ret;
+               goto out;
 
-       k = cpus_addr(mask);
+       k = cpumask_bits(mask);
        ret = compat_put_bitmap(user_mask_ptr, k, min_length * 8);
-       if (ret)
-               return ret;
+       if (ret == 0)
+               ret = min_length;
 
-       return min_length;
+out:
+       free_cpumask_var(mask);
+       return ret;
 }
 
 int get_compat_itimerspec(struct itimerspec *dst,