Merge branch 'component-for-driver' of git://ftp.arm.linux.org.uk/~rmk/linux-arm into driver-core-next

Russell writes:

These updates fix one bug in the component helper where the matched
components are not properly cleaned up when the master fails to bind.
I'll provide a version of this for stable trees if it's deemed that
we need to backport it.

The second patch causes the component helper to ignore duplicate
matches when adding components - this is something that was originally
needed for imx-drm, but since that has now been updated, we no longer
need to skip over a component which has already been matched.

The final patch starts the process of updating the component helper
API to achieve two goals: to allow the API to be more efficient when
deferred probing occurs, and to allow for future improvements to the
component helper without having a major impact on the users.

This represents groundwork for some other changes; once this has been
merged, I will then send two further pull requests (one for the staging
tree, and one for the DRM tree) to update the drivers to the new API.
This will result in these three commits being shared with those trees.

1 files changed, 47 insertions, 10 deletions

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index e60837dc785c..33514d88fef9 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -941,6 +941,37 @@ unlock:
 	spin_unlock(ptl);
 }
 
+/*
+ * Save CONFIG_DEBUG_PAGEALLOC from faulting falsely on tail pages
+ * during copy_user_huge_page()'s copy_page_rep(): in the case when
+ * the source page gets split and a tail freed before copy completes.
+ * Called under pmd_lock of checked pmd, so safe from splitting itself.
+ */
+static void get_user_huge_page(struct page *page)
+{
+	if (IS_ENABLED(CONFIG_DEBUG_PAGEALLOC)) {
+		struct page *endpage = page + HPAGE_PMD_NR;
+
+		atomic_add(HPAGE_PMD_NR, &page->_count);
+		while (++page < endpage)
+			get_huge_page_tail(page);
+	} else {
+		get_page(page);
+	}
+}
+
+static void put_user_huge_page(struct page *page)
+{
+	if (IS_ENABLED(CONFIG_DEBUG_PAGEALLOC)) {
+		struct page *endpage = page + HPAGE_PMD_NR;
+
+		while (page < endpage)
+			put_page(page++);
+	} else {
+		put_page(page);
+	}
+}
+
 static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm,
 					struct vm_area_struct *vma,
 					unsigned long address,
@@ -1074,7 +1105,7 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
 		ret |= VM_FAULT_WRITE;
 		goto out_unlock;
 	}
-	get_page(page);
+	get_user_huge_page(page);
 	spin_unlock(ptl);
 alloc:
 	if (transparent_hugepage_enabled(vma) &&
@@ -1095,7 +1126,7 @@ alloc:
 				split_huge_page(page);
 				ret |= VM_FAULT_FALLBACK;
 			}
-			put_page(page);
+			put_user_huge_page(page);
 		}
 		count_vm_event(THP_FAULT_FALLBACK);
 		goto out;
@@ -1105,7 +1136,7 @@ alloc:
 		put_page(new_page);
 		if (page) {
 			split_huge_page(page);
-			put_page(page);
+			put_user_huge_page(page);
 		} else
 			split_huge_page_pmd(vma, address, pmd);
 		ret |= VM_FAULT_FALLBACK;
@@ -1127,7 +1158,7 @@ alloc:
 
 	spin_lock(ptl);
 	if (page)
-		put_page(page);
+		put_user_huge_page(page);
 	if (unlikely(!pmd_same(*pmd, orig_pmd))) {
 		spin_unlock(ptl);
 		mem_cgroup_uncharge_page(new_page);
@@ -2392,8 +2423,6 @@ static void collapse_huge_page(struct mm_struct *mm,
 	pmd = mm_find_pmd(mm, address);
 	if (!pmd)
 		goto out;
-	if (pmd_trans_huge(*pmd))
-		goto out;
 
 	anon_vma_lock_write(vma->anon_vma);
 
@@ -2492,8 +2521,6 @@ static int khugepaged_scan_pmd(struct mm_struct *mm,
 	pmd = mm_find_pmd(mm, address);
 	if (!pmd)
 		goto out;
-	if (pmd_trans_huge(*pmd))
-		goto out;
 
 	memset(khugepaged_node_load, 0, sizeof(khugepaged_node_load));
 	pte = pte_offset_map_lock(mm, pmd, address, &ptl);
@@ -2846,12 +2873,22 @@ void split_huge_page_pmd_mm(struct mm_struct *mm, unsigned long address,
 static void split_huge_page_address(struct mm_struct *mm,
 				    unsigned long address)
 {
+	pgd_t *pgd;
+	pud_t *pud;
 	pmd_t *pmd;
 
 	VM_BUG_ON(!(address & ~HPAGE_PMD_MASK));
 
-	pmd = mm_find_pmd(mm, address);
-	if (!pmd)
+	pgd = pgd_offset(mm, address);
+	if (!pgd_present(*pgd))
+		return;
+
+	pud = pud_offset(pgd, address);
+	if (!pud_present(*pud))
+		return;
+
+	pmd = pmd_offset(pud, address);
+	if (!pmd_present(*pmd))
 		return;
 	/*
 	 * Caller holds the mmap_sem write mode, so a huge pmd cannot