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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2016-01-21 16:40:25 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-21 17:20:51 -0800
commitb6ec57f4b92e9bae4617f7d98a054d45370284bb (patch)
tree31b894dc2fa7c8a885baa4be7094c73002999719 /mm
parent404a47410c26a115123885977053e9a1a4460929 (diff)
downloadlwn-b6ec57f4b92e9bae4617f7d98a054d45370284bb.tar.gz
lwn-b6ec57f4b92e9bae4617f7d98a054d45370284bb.zip
thp: change pmd_trans_huge_lock() interface to return ptl
After THP refcounting rework we have only two possible return values from pmd_trans_huge_lock(): success and failure. Return-by-pointer for ptl doesn't make much sense in this case. Let's convert pmd_trans_huge_lock() to return ptl on success and NULL on failure. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Minchan Kim <minchan@kernel.org> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/huge_memory.c24
-rw-r--r--mm/memcontrol.c6
-rw-r--r--mm/mincore.c3
3 files changed, 20 insertions, 13 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 8ad580273521..2d1ffe9d0e26 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1560,7 +1560,8 @@ int madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
struct mm_struct *mm = tlb->mm;
int ret = 0;
- if (!pmd_trans_huge_lock(pmd, vma, &ptl))
+ ptl = pmd_trans_huge_lock(pmd, vma);
+ if (!ptl)
goto out_unlocked;
orig_pmd = *pmd;
@@ -1627,7 +1628,8 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
pmd_t orig_pmd;
spinlock_t *ptl;
- if (!__pmd_trans_huge_lock(pmd, vma, &ptl))
+ ptl = __pmd_trans_huge_lock(pmd, vma);
+ if (!ptl)
return 0;
/*
* For architectures like ppc64 we look at deposited pgtable
@@ -1690,7 +1692,8 @@ bool move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma,
* We don't have to worry about the ordering of src and dst
* ptlocks because exclusive mmap_sem prevents deadlock.
*/
- if (__pmd_trans_huge_lock(old_pmd, vma, &old_ptl)) {
+ old_ptl = __pmd_trans_huge_lock(old_pmd, vma);
+ if (old_ptl) {
new_ptl = pmd_lockptr(mm, new_pmd);
if (new_ptl != old_ptl)
spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
@@ -1724,7 +1727,8 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
spinlock_t *ptl;
int ret = 0;
- if (__pmd_trans_huge_lock(pmd, vma, &ptl)) {
+ ptl = __pmd_trans_huge_lock(pmd, vma);
+ if (ptl) {
pmd_t entry;
bool preserve_write = prot_numa && pmd_write(*pmd);
ret = 1;
@@ -1760,14 +1764,14 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
* Note that if it returns true, this routine returns without unlocking page
* table lock. So callers must unlock it.
*/
-bool __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma,
- spinlock_t **ptl)
+spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma)
{
- *ptl = pmd_lock(vma->vm_mm, pmd);
+ spinlock_t *ptl;
+ ptl = pmd_lock(vma->vm_mm, pmd);
if (likely(pmd_trans_huge(*pmd) || pmd_devmap(*pmd)))
- return true;
- spin_unlock(*ptl);
- return false;
+ return ptl;
+ spin_unlock(ptl);
+ return NULL;
}
#define VM_NO_THP (VM_SPECIAL | VM_HUGETLB | VM_SHARED | VM_MAYSHARE)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index ca052f2a4a0b..d06cae2de783 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4638,7 +4638,8 @@ static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
pte_t *pte;
spinlock_t *ptl;
- if (pmd_trans_huge_lock(pmd, vma, &ptl)) {
+ ptl = pmd_trans_huge_lock(pmd, vma);
+ if (ptl) {
if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
mc.precharge += HPAGE_PMD_NR;
spin_unlock(ptl);
@@ -4826,7 +4827,8 @@ static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
union mc_target target;
struct page *page;
- if (pmd_trans_huge_lock(pmd, vma, &ptl)) {
+ ptl = pmd_trans_huge_lock(pmd, vma);
+ if (ptl) {
if (mc.precharge < HPAGE_PMD_NR) {
spin_unlock(ptl);
return 0;
diff --git a/mm/mincore.c b/mm/mincore.c
index 2a565ed8bb49..563f32045490 100644
--- a/mm/mincore.c
+++ b/mm/mincore.c
@@ -117,7 +117,8 @@ static int mincore_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
unsigned char *vec = walk->private;
int nr = (end - addr) >> PAGE_SHIFT;
- if (pmd_trans_huge_lock(pmd, vma, &ptl)) {
+ ptl = pmd_trans_huge_lock(pmd, vma);
+ if (ptl) {
memset(vec, 1, nr);
spin_unlock(ptl);
goto out;