[LU-6497] strange code in ll_page_mkwrite0

• Type: Bug
• Resolution: Unresolved
• Priority: Minor
• Labels: easy smatch
• Severity: 3
• Assignee: WC Triage
• Reporter: Oleg Drokin

Description

I am playing with new version of smatch and it highlighted this interesting piece in ll_page_mkwrite0:

        if (result == 0) {
                struct inode *inode = vma->vm_file->f_dentry->d_inode;
                struct ll_inode_info *lli = ll_i2info(inode);

                lock_page(vmpage);
                if (vmpage->mapping == NULL) {
                        unlock_page(vmpage);

                        /* page was truncated and lock was cancelled, return
                         * ENODATA so that VM_FAULT_NOPAGE will be returned
                         * to handle_mm_fault(). */
                        if (result == 0)
                                result = -ENODATA;

So we are on a path that already checked result to be 0 and then we check again? Is there a missing call to somewhere?