On Sat, 2018-02-10 at 23:59 +0800, Donglin Peng wrote: > There are two redundant assignments in the traverse() function, because > the while loop will break after these two assignments, and after that > the variable index will be assigned to m->index again. [] > diff --git a/fs/seq_file.c b/fs/seq_file.c [] > @@ -120,14 +120,12 @@ static int traverse(struct seq_file *m, loff_t offset) > if (pos + m->count > offset) { > m->from = offset - pos; > m->count -= m->from; > - m->index = index; > break; > } > pos += m->count; > m->count = 0; > if (pos == offset) { > index++; > - m->index = index; > break; > } > p = m->op->next(m, p, &index); Of course this looks correct, but how are you _absolutely sure_ about this? Perhaps the m->op->stop(m, p) call below the break, which takes m as an argument, needs an updated m->index. Unless you can verify _all_ the indirect paths that stop() can take, this patch may not be correct.