On 3/26/22 23:59, Xiaomeng Tong wrote:
On Sat, 26 Mar 2022 22:38:05 -0700, Guenter Roeck linux@roeck-us.net wrote:
@@ -103,11 +103,16 @@ nvkm_control_mthd_pstate_attr(struct nvkm_control *ctrl, void *data, u32 size) return -EINVAL; if (args->v0.state != NVIF_CONTROL_PSTATE_ATTR_V0_STATE_CURRENT) {
list_for_each_entry(pstate, &clk->states, head) {if (i++ == args->v0.state)
list_for_each_entry(iter, &clk->states, head) {if (i++ == args->v0.state) {pstate = iter;Is iter and the assignment really necessary ? Unless I am missing something, list_for_each_entry() always assigns pos (pstate/iter), even if the list is empty. If nothing is found, pstate would be NULL at the end, so
the pstate will not be NULL at the end! so the assignment is necessary! #define list_for_each_entry(pos, head, member) \ for (pos = __container_of((head)->next, pos, member); \ &pos->member != (head); \ pos = __container_of(pos->member.next, pos, member))
Uuh, yes, you are correct. Sorry for the noise.
Guenter