Update Linux to v5.10.157

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.157.tar.xz

Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
Change-Id: I7b30d9e98d8c465d6b44de8e7433b4a40b3289ba
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index fce705f..d8c63d7 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2387,11 +2387,11 @@
 		page = alloc_buddy_huge_page_with_mpol(h, vma, addr);
 		if (!page)
 			goto out_uncharge_cgroup;
+		spin_lock(&hugetlb_lock);
 		if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
 			SetPagePrivate(page);
 			h->resv_huge_pages--;
 		}
-		spin_lock(&hugetlb_lock);
 		list_add(&page->lru, &h->hugepage_activelist);
 		/* Fall through */
 	}
@@ -4337,6 +4337,7 @@
 	spinlock_t *ptl;
 	unsigned long haddr = address & huge_page_mask(h);
 	bool new_page = false;
+	u32 hash = hugetlb_fault_mutex_hash(mapping, idx);
 
 	/*
 	 * Currently, we are forced to kill the process in the event the
@@ -4346,7 +4347,7 @@
 	if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
 		pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
 			   current->pid);
-		return ret;
+		goto out;
 	}
 
 	/*
@@ -4365,7 +4366,6 @@
 		 * Check for page in userfault range
 		 */
 		if (userfaultfd_missing(vma)) {
-			u32 hash;
 			struct vm_fault vmf = {
 				.vma = vma,
 				.address = haddr,
@@ -4380,17 +4380,14 @@
 			};
 
 			/*
-			 * hugetlb_fault_mutex and i_mmap_rwsem must be
-			 * dropped before handling userfault.  Reacquire
-			 * after handling fault to make calling code simpler.
+			 * vma_lock and hugetlb_fault_mutex must be dropped
+			 * before handling userfault. Also mmap_lock will
+			 * be dropped during handling userfault, any vma
+			 * operation should be careful from here.
 			 */
-			hash = hugetlb_fault_mutex_hash(mapping, idx);
 			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 			i_mmap_unlock_read(mapping);
-			ret = handle_userfault(&vmf, VM_UFFD_MISSING);
-			i_mmap_lock_read(mapping);
-			mutex_lock(&hugetlb_fault_mutex_table[hash]);
-			goto out;
+			return handle_userfault(&vmf, VM_UFFD_MISSING);
 		}
 
 		page = alloc_huge_page(vma, haddr, 0);
@@ -4497,6 +4494,8 @@
 
 	unlock_page(page);
 out:
+	mutex_unlock(&hugetlb_fault_mutex_table[hash]);
+	i_mmap_unlock_read(mapping);
 	return ret;
 
 backout:
@@ -4592,10 +4591,12 @@
 	mutex_lock(&hugetlb_fault_mutex_table[hash]);
 
 	entry = huge_ptep_get(ptep);
-	if (huge_pte_none(entry)) {
-		ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
-		goto out_mutex;
-	}
+	if (huge_pte_none(entry))
+		/*
+		 * hugetlb_no_page will drop vma lock and hugetlb fault
+		 * mutex internally, which make us return immediately.
+		 */
+		return hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
 
 	ret = 0;
 
@@ -5465,7 +5466,14 @@
 	pud_clear(pud);
 	put_page(virt_to_page(ptep));
 	mm_dec_nr_pmds(mm);
-	*addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
+	/*
+	 * This update of passed address optimizes loops sequentially
+	 * processing addresses in increments of huge page size (PMD_SIZE
+	 * in this case).  By clearing the pud, a PUD_SIZE area is unmapped.
+	 * Update address to the 'last page' in the cleared area so that
+	 * calling loop can move to first page past this area.
+	 */
+	*addr |= PUD_SIZE - PMD_SIZE;
 	return 1;
 }
 #define want_pmd_share()	(1)