On Thu, Jan 15, 2015 at 05:54:55PM +0800, Dave Young wrote:
> > out_add_entry:
> > - for (j = i - 1; j > 0; j--) {
> > + for (j = i - 1; j >= 0; j--) {
> > entry = *(map_entries + j);
> > kobject_put(&entry->kobj);
> > }
>
> see below code, as for an invalid entry with i = 0, it will be not
> assigned to *(map_entries + i)
Yes. Of course, if the first iteration fails then we want the free loop
to be a noop and it is in my code as well. j = -1. -1 is not >= 0.
The problem is in later iterations.
>
> ---
> for (i = 0; i < nr_efi_runtime_map; i++) {
> entry = add_sysfs_runtime_map_entry(efi_kobj, i);
Assume that this is the second iteration and "i == 1".
> if (IS_ERR(entry)) {
> ret = PTR_ERR(entry);
> goto out_add_entry;
Assume it fails so we hit this goto. We want to free the first entry.
> }
> *(map_entries + i) = entry;
> }
>
> return 0;
> out_add_entry:
> for (j = i - 1; j > 0; j--) {
> entry = *(map_entries + j);
In your code, "j == 1 - 1" and that's not greater than zero so we don't
enter this loop. In my code, we go through the loop one time.
By the way this code would be a lot more clear if you used arrays.
"map_entries[j]" is more clear than "*(map_entries + j)". Even in the
other patch, passing "&foo[i]" is more clear than "foo + i".
regards,
dan carpenter
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