On Wed, Sep 04, 2019 at 06:25:19PM +0000, Weiny, Ira wrote: > > On 9/4/19 12:26 PM, zhong jiang wrote: > > > With the help of unsigned_lesser_than_zero.cocci. Unsigned 'nr_pages"' > > > compare with zero. And __get_user_pages_locked will return an long > > value. > > > Hence, Convert the long to compare with zero is feasible. > > > > It would be nicer if the parameter nr_pages was long again instead of > > unsigned long (note there are two variants of the function, so both should be > > changed). > > Why? What does it mean for nr_pages to be negative? The check below seems valid. Unsigned can be 0 so the check can fail. IOW Checking unsigned > 0 seems ok. > > What am I missing? __get_user_pages can return a negative errno.
