On 19/09/2018 10:48, Janosch Frank wrote:
> Not yet sure if I'll keep this.
>
> The walk should only walk and not check I, but then it looks way
> nicer.
I agree, while it looks nicer, conceptually it is better to return if
"there is something" - in contrast to "pte_none" where there definitely
isn't "something".
>
> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> ---
> arch/s390/mm/gmap.c | 17 +++++++----------
> 1 file changed, 7 insertions(+), 10 deletions(-)
>
> diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
> index 0220a32aa2b9..8d5ce51637eb 100644
> --- a/arch/s390/mm/gmap.c
> +++ b/arch/s390/mm/gmap.c
> @@ -952,7 +952,8 @@ static inline pmd_t *gmap_pmd_op_walk(struct gmap *gmap, unsigned long gaddr,
> }
>
> pmdp = (pmd_t *) gmap_table_walk(gmap, gaddr, 1);
> - if (!pmdp || pmd_none(*pmdp)) {
> + if (!pmdp || pmd_none(*pmdp) ||
> + pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID) {
> if (*ptl)
> spin_unlock(*ptl);
> pmdp = NULL;
> @@ -1161,7 +1162,7 @@ static int gmap_protect_range(struct gmap *gmap, unsigned long gaddr,
> return vmaddr;
> vmaddr |= gaddr & ~PMD_MASK;
> pmdp = gmap_pmd_op_walk(gmap, gaddr, vmaddr, &ptl_pmd);
> - if (pmdp && !(pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID)) {
> + if (pmdp) {
> if (!pmd_large(*pmdp)) {
> ptep = gmap_pte_from_pmd(gmap, pmdp, gaddr,
> &ptl_pte);
> @@ -1266,7 +1267,7 @@ int gmap_read_table(struct gmap *gmap, unsigned long gaddr, unsigned long *val)
> if (IS_ERR_VALUE(vmaddr))
> return vmaddr;
> pmdp = gmap_pmd_op_walk(gmap, gaddr, vmaddr, &ptl_pmd);
> - if (pmdp && !(pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID)) {
> + if (pmdp) {
> if (!pmd_large(*pmdp)) {
> ptep = gmap_pte_from_pmd(gmap, pmdp, vmaddr, &ptl_pte);
> if (ptep) {
> @@ -1380,7 +1381,7 @@ static int gmap_protect_rmap(struct gmap *sg, unsigned long raddr,
> return vmaddr;
> vmaddr |= paddr & ~PMD_MASK;
> pmdp = gmap_pmd_op_walk(parent, paddr, vmaddr, &ptl_pmd);
> - if (pmdp && !(pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID)) {
> + if (pmdp) {
> if (!pmd_large(*pmdp)) {
> ptl_pte = NULL;
> ptep = gmap_pte_from_pmd(parent, pmdp, paddr,
> @@ -2362,8 +2363,7 @@ int gmap_shadow_segment(struct gmap *sg, unsigned long saddr, pmd_t pmd)
> break;
> }
> spmd = *spmdp;
> - if (!(pmd_val(spmd) & _SEGMENT_ENTRY_INVALID) &&
> - !((pmd_val(spmd) & _SEGMENT_ENTRY_PROTECT) &&
> + if (!((pmd_val(spmd) & _SEGMENT_ENTRY_PROTECT) &&
> !(pmd_val(pmd) & _SEGMENT_ENTRY_PROTECT))) {
>
> pmd_val(*spmdp) |= _SEGMENT_ENTRY_GMAP_VSIE;
> @@ -2436,7 +2436,7 @@ int gmap_shadow_page(struct gmap *sg, unsigned long saddr, pte_t pte)
> break;
> rc = -EAGAIN;
> spmdp = gmap_pmd_op_walk(parent, paddr, vmaddr, &ptl_pmd);
> - if (spmdp && !(pmd_val(*spmdp) & _SEGMENT_ENTRY_INVALID)) {
> + if (spmdp) {
> /* Get page table pointer */
> tptep = (pte_t *) gmap_table_walk(sg, saddr, 0);
> if (!tptep) {
> @@ -2869,9 +2869,6 @@ EXPORT_SYMBOL_GPL(gmap_pmdp_idte_global);
> bool gmap_test_and_clear_dirty_pmd(struct gmap *gmap, pmd_t *pmdp,
> unsigned long gaddr, unsigned long vmaddr)
> {
> - if (pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID)
> - return false;
> -
> /* Already protected memory, which did not change is clean */
> if (pmd_val(*pmdp) & _SEGMENT_ENTRY_PROTECT &&
> !(pmd_val(*pmdp) & _SEGMENT_ENTRY_GMAP_UC))
>
--
Thanks,
David / dhildenb
