Merge tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kerne…

…l/git/rdma/rdma

Pull hmm updates from Jason Gunthorpe:
 "This is more cleanup and consolidation of the hmm APIs and the very
  strongly related mmu_notifier interfaces. Many places across the tree
  using these interfaces are touched in the process. Beyond that a
  cleanup to the page walker API and a few memremap related changes
  round out the series:

   - General improvement of hmm_range_fault() and related APIs, more
     documentation, bug fixes from testing, API simplification &
     consolidation, and unused API removal

   - Simplify the hmm related kconfigs to HMM_MIRROR and DEVICE_PRIVATE,
     and make them internal kconfig selects

   - Hoist a lot of code related to mmu notifier attachment out of
     drivers by using a refcount get/put attachment idiom and remove the
     convoluted mmu_notifier_unregister_no_release() and related APIs.

   - General API improvement for the migrate_vma API and revision of its
     only user in nouveau

   - Annotate mmu_notifiers with lockdep and sleeping region debugging

  Two series unrelated to HMM or mmu_notifiers came along due to
  dependencies:

   - Allow pagemap's memremap_pages family of APIs to work without
     providing a struct device

   - Make walk_page_range() and related use a constant structure for
     function pointers"

* tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (75 commits)
  libnvdimm: Enable unit test infrastructure compile checks
  mm, notifier: Catch sleeping/blocking for !blockable
  kernel.h: Add non_block_start/end()
  drm/radeon: guard against calling an unpaired radeon_mn_unregister()
  csky: add missing brackets in a macro for tlb.h
  pagewalk: use lockdep_assert_held for locking validation
  pagewalk: separate function pointers from iterator data
  mm: split out a new pagewalk.h header from mm.h
  mm/mmu_notifiers: annotate with might_sleep()
  mm/mmu_notifiers: prime lockdep
  mm/mmu_notifiers: add a lockdep map for invalidate_range_start/end
  mm/mmu_notifiers: remove the __mmu_notifier_invalidate_range_start/end exports
  mm/hmm: hmm_range_fault() infinite loop
  mm/hmm: hmm_range_fault() NULL pointer bug
  mm/hmm: fix hmm_range_fault()'s handling of swapped out pages
  mm/mmu_notifiers: remove unregister_no_release
  RDMA/odp: remove ib_ucontext from ib_umem
  RDMA/odp: use mmu_notifier_get/put for 'struct ib_ucontext_per_mm'
  RDMA/mlx5: Use odp instead of mr->umem in pagefault_mr
  RDMA/mlx5: Use ib_umem_start instead of umem.address
  ...

Documentation/vm/hmm.rst

@@ -192,15 +192,14 @@ read only, or fully unmap, etc.). The device must complete the update before
 the driver callback returns.
 
 When the device driver wants to populate a range of virtual addresses, it can
-use either::
+use::
 
-  long hmm_range_snapshot(struct hmm_range *range);
-  long hmm_range_fault(struct hmm_range *range, bool block);
+  long hmm_range_fault(struct hmm_range *range, unsigned int flags);
 
-The first one (hmm_range_snapshot()) will only fetch present CPU page table
+With the HMM_RANGE_SNAPSHOT flag, it will only fetch present CPU page table
 entries and will not trigger a page fault on missing or non-present entries.
-The second one does trigger a page fault on missing or read-only entries if
-write access is requested (see below). Page faults use the generic mm page
+Without that flag, it does trigger a page fault on missing or read-only entries
+if write access is requested (see below). Page faults use the generic mm page
 fault code path just like a CPU page fault.
 
 Both functions copy CPU page table entries into their pfns array argument. Each
@@ -223,24 +222,24 @@ The usage pattern is::
       range.flags = ...;
       range.values = ...;
       range.pfn_shift = ...;
-      hmm_range_register(&range);
+      hmm_range_register(&range, mirror);
 
       /*
        * Just wait for range to be valid, safe to ignore return value as we
-       * will use the return value of hmm_range_snapshot() below under the
+       * will use the return value of hmm_range_fault() below under the
        * mmap_sem to ascertain the validity of the range.
        */
       hmm_range_wait_until_valid(&range, TIMEOUT_IN_MSEC);
 
  again:
       down_read(&mm->mmap_sem);
-      ret = hmm_range_snapshot(&range);
+      ret = hmm_range_fault(&range, HMM_RANGE_SNAPSHOT);
       if (ret) {
           up_read(&mm->mmap_sem);
           if (ret == -EBUSY) {
             /*
              * No need to check hmm_range_wait_until_valid() return value
-             * on retry we will get proper error with hmm_range_snapshot()
+             * on retry we will get proper error with hmm_range_fault()
              */
             hmm_range_wait_until_valid(&range, TIMEOUT_IN_MSEC);
             goto again;
@@ -340,58 +339,8 @@ Migration to and from device memory
 ===================================
 
 Because the CPU cannot access device memory, migration must use the device DMA
-engine to perform copy from and to device memory. For this we need a new
-migration helper::
-
- int migrate_vma(const struct migrate_vma_ops *ops,
-                 struct vm_area_struct *vma,
-                 unsigned long mentries,
-                 unsigned long start,
-                 unsigned long end,
-                 unsigned long *src,
-                 unsigned long *dst,
-                 void *private);
-
-Unlike other migration functions it works on a range of virtual address, there
-are two reasons for that. First, device DMA copy has a high setup overhead cost
-and thus batching multiple pages is needed as otherwise the migration overhead
-makes the whole exercise pointless. The second reason is because the
-migration might be for a range of addresses the device is actively accessing.
-
-The migrate_vma_ops struct defines two callbacks. First one (alloc_and_copy())
-controls destination memory allocation and copy operation. Second one is there
-to allow the device driver to perform cleanup operations after migration::
-
- struct migrate_vma_ops {
-     void (*alloc_and_copy)(struct vm_area_struct *vma,
-                            const unsigned long *src,
-                            unsigned long *dst,
-                            unsigned long start,
-                            unsigned long end,
-                            void *private);
-     void (*finalize_and_map)(struct vm_area_struct *vma,
-                              const unsigned long *src,
-                              const unsigned long *dst,
-                              unsigned long start,
-                              unsigned long end,
-                              void *private);
- };
-
-It is important to stress that these migration helpers allow for holes in the
-virtual address range. Some pages in the range might not be migrated for all
-the usual reasons (page is pinned, page is locked, ...). This helper does not
-fail but just skips over those pages.
-
-The alloc_and_copy() might decide to not migrate all pages in the
-range (for reasons under the callback control). For those, the callback just
-has to leave the corresponding dst entry empty.
-
-Finally, the migration of the struct page might fail (for file backed page) for
-various reasons (failure to freeze reference, or update page cache, ...). If
-that happens, then the finalize_and_map() can catch any pages that were not
-migrated. Note those pages were still copied to a new page and thus we wasted
-bandwidth but this is considered as a rare event and a price that we are
-willing to pay to keep all the code simpler.
+engine to perform copy from and to device memory. For this we need to use
+migrate_vma_setup(), migrate_vma_pages(), and migrate_vma_finalize() helpers.
 
 
 Memory cgroup (memcg) and rss accounting

arch/csky/include/asm/tlb.h

@@ -8,14 +8,14 @@
 
 #define tlb_start_vma(tlb, vma) \
 	do { \
-		if (!tlb->fullmm) \
-			flush_cache_range(vma, vma->vm_start, vma->vm_end); \
+		if (!(tlb)->fullmm) \
+			flush_cache_range(vma, (vma)->vm_start, (vma)->vm_end); \
 	}  while (0)
 
 #define tlb_end_vma(tlb, vma) \
 	do { \
-		if (!tlb->fullmm) \
-			flush_tlb_range(vma, vma->vm_start, vma->vm_end); \
+		if (!(tlb)->fullmm) \
+			flush_tlb_range(vma, (vma)->vm_start, (vma)->vm_end); \
 	}  while (0)
 
 #define tlb_flush(tlb) flush_tlb_mm((tlb)->mm)

arch/openrisc/kernel/dma.c

@@ -16,6 +16,7 @@
  */
 
 #include <linux/dma-noncoherent.h>
+#include <linux/pagewalk.h>
 
 #include <asm/cpuinfo.h>
 #include <asm/spr_defs.h>
@@ -43,6 +44,10 @@ page_set_nocache(pte_t *pte, unsigned long addr,
 	return 0;
 }
 
+static const struct mm_walk_ops set_nocache_walk_ops = {
+	.pte_entry		= page_set_nocache,
+};
+
 static int
 page_clear_nocache(pte_t *pte, unsigned long addr,
 		   unsigned long next, struct mm_walk *walk)
@@ -58,6 +63,10 @@ page_clear_nocache(pte_t *pte, unsigned long addr,
 	return 0;
 }
 
+static const struct mm_walk_ops clear_nocache_walk_ops = {
+	.pte_entry		= page_clear_nocache,
+};
+
 /*
  * Alloc "coherent" memory, which for OpenRISC means simply uncached.
  *
@@ -80,10 +89,6 @@ arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 {
 	unsigned long va;
 	void *page;
-	struct mm_walk walk = {
-		.pte_entry = page_set_nocache,
-		.mm = &init_mm
-	};
 
 	page = alloc_pages_exact(size, gfp | __GFP_ZERO);
 	if (!page)
@@ -98,7 +103,8 @@ arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 	 * We need to iterate through the pages, clearing the dcache for
 	 * them and setting the cache-inhibit bit.
 	 */
-	if (walk_page_range(va, va + size, &walk)) {
+	if (walk_page_range(&init_mm, va, va + size, &set_nocache_walk_ops,
+			NULL)) {
 		free_pages_exact(page, size);
 		return NULL;
 	}
@@ -111,13 +117,10 @@ arch_dma_free(struct device *dev, size_t size, void *vaddr,
 		dma_addr_t dma_handle, unsigned long attrs)
 {
 	unsigned long va = (unsigned long)vaddr;
-	struct mm_walk walk = {
-		.pte_entry = page_clear_nocache,
-		.mm = &init_mm
-	};
 
 	/* walk_page_range shouldn't be able to fail here */
-	WARN_ON(walk_page_range(va, va + size, &walk));
+	WARN_ON(walk_page_range(&init_mm, va, va + size,
+			&clear_nocache_walk_ops, NULL));
 
 	free_pages_exact(vaddr, size);
 }

arch/powerpc/mm/book3s64/subpage_prot.c

@@ -7,7 +7,7 @@
 #include <linux/kernel.h>
 #include <linux/gfp.h>
 #include <linux/types.h>
-#include <linux/mm.h>
+#include <linux/pagewalk.h>
 #include <linux/hugetlb.h>
 #include <linux/syscalls.h>
 
@@ -139,14 +139,14 @@ static int subpage_walk_pmd_entry(pmd_t *pmd, unsigned long addr,
 	return 0;
 }
 
+static const struct mm_walk_ops subpage_walk_ops = {
+	.pmd_entry	= subpage_walk_pmd_entry,
+};
+
 static void subpage_mark_vma_nohuge(struct mm_struct *mm, unsigned long addr,
 				    unsigned long len)
 {
 	struct vm_area_struct *vma;
-	struct mm_walk subpage_proto_walk = {
-		.mm = mm,
-		.pmd_entry = subpage_walk_pmd_entry,
-	};
 
 	/*
 	 * We don't try too hard, we just mark all the vma in that range
@@ -163,7 +163,7 @@ static void subpage_mark_vma_nohuge(struct mm_struct *mm, unsigned long addr,
 		if (vma->vm_start >= (addr + len))
 			break;
 		vma->vm_flags |= VM_NOHUGEPAGE;
-		walk_page_vma(vma, &subpage_proto_walk);
+		walk_page_vma(vma, &subpage_walk_ops, NULL);
 		vma = vma->vm_next;
 	}
 }

arch/s390/mm/gmap.c

@@ -9,7 +9,7 @@
  */
 
 #include <linux/kernel.h>
-#include <linux/mm.h>
+#include <linux/pagewalk.h>
 #include <linux/swap.h>
 #include <linux/smp.h>
 #include <linux/spinlock.h>
@@ -2521,13 +2521,9 @@ static int __zap_zero_pages(pmd_t *pmd, unsigned long start,
 	return 0;
 }
 
-static inline void zap_zero_pages(struct mm_struct *mm)
-{
-	struct mm_walk walk = { .pmd_entry = __zap_zero_pages };
-
-	walk.mm = mm;
-	walk_page_range(0, TASK_SIZE, &walk);
-}
+static const struct mm_walk_ops zap_zero_walk_ops = {
+	.pmd_entry	= __zap_zero_pages,
+};
 
 /*
  * switch on pgstes for its userspace process (for kvm)
@@ -2546,7 +2542,7 @@ int s390_enable_sie(void)
 	mm->context.has_pgste = 1;
 	/* split thp mappings and disable thp for future mappings */
 	thp_split_mm(mm);
-	zap_zero_pages(mm);
+	walk_page_range(mm, 0, TASK_SIZE, &zap_zero_walk_ops, NULL);
 	up_write(&mm->mmap_sem);
 	return 0;
 }
@@ -2589,12 +2585,13 @@ static int __s390_enable_skey_hugetlb(pte_t *pte, unsigned long addr,
 	return 0;
 }
 
+static const struct mm_walk_ops enable_skey_walk_ops = {
+	.hugetlb_entry		= __s390_enable_skey_hugetlb,
+	.pte_entry		= __s390_enable_skey_pte,
+};
+
 int s390_enable_skey(void)
 {
-	struct mm_walk walk = {
-		.hugetlb_entry = __s390_enable_skey_hugetlb,
-		.pte_entry = __s390_enable_skey_pte,
-	};
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
 	int rc = 0;
@@ -2614,8 +2611,7 @@ int s390_enable_skey(void)
 	}
 	mm->def_flags &= ~VM_MERGEABLE;
 
-	walk.mm = mm;
-	walk_page_range(0, TASK_SIZE, &walk);
+	walk_page_range(mm, 0, TASK_SIZE, &enable_skey_walk_ops, NULL);
 
 out_up:
 	up_write(&mm->mmap_sem);
@@ -2633,13 +2629,14 @@ static int __s390_reset_cmma(pte_t *pte, unsigned long addr,
 	return 0;
 }
 
+static const struct mm_walk_ops reset_cmma_walk_ops = {
+	.pte_entry		= __s390_reset_cmma,
+};
+
 void s390_reset_cmma(struct mm_struct *mm)
 {
-	struct mm_walk walk = { .pte_entry = __s390_reset_cmma };
-
 	down_write(&mm->mmap_sem);
-	walk.mm = mm;
-	walk_page_range(0, TASK_SIZE, &walk);
+	walk_page_range(mm, 0, TASK_SIZE, &reset_cmma_walk_ops, NULL);
 	up_write(&mm->mmap_sem);
 }
 EXPORT_SYMBOL_GPL(s390_reset_cmma);

drivers/gpu/drm/amd/amdgpu/Kconfig

@@ -27,7 +27,9 @@ config DRM_AMDGPU_CIK
 config DRM_AMDGPU_USERPTR
 	bool "Always enable userptr write support"
 	depends on DRM_AMDGPU
-	depends on HMM_MIRROR
+	depends on MMU
+	select HMM_MIRROR
+	select MMU_NOTIFIER
 	help
 	  This option selects CONFIG_HMM and CONFIG_HMM_MIRROR if it
 	  isn't already selected to enabled full userptr support.

drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c

@@ -35,6 +35,7 @@
 #include <linux/pm_runtime.h>
 #include <linux/vga_switcheroo.h>
 #include <drm/drm_probe_helper.h>
+#include <linux/mmu_notifier.h>
 
 #include "amdgpu.h"
 #include "amdgpu_irq.h"
@@ -1469,6 +1470,7 @@ static void __exit amdgpu_exit(void)
 	amdgpu_unregister_atpx_handler();
 	amdgpu_sync_fini();
 	amdgpu_fence_slab_fini();
+	mmu_notifier_synchronize();
 }
 
 module_init(amdgpu_init);

drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c

@@ -195,13 +195,14 @@ static void amdgpu_mn_invalidate_node(struct amdgpu_mn_node *node,
  * Block for operations on BOs to finish and mark pages as accessed and
  * potentially dirty.
  */
-static int amdgpu_mn_sync_pagetables_gfx(struct hmm_mirror *mirror,
-			const struct hmm_update *update)
+static int
+amdgpu_mn_sync_pagetables_gfx(struct hmm_mirror *mirror,
+			      const struct mmu_notifier_range *update)
 {
 	struct amdgpu_mn *amn = container_of(mirror, struct amdgpu_mn, mirror);
 	unsigned long start = update->start;
 	unsigned long end = update->end;
-	bool blockable = update->blockable;
+	bool blockable = mmu_notifier_range_blockable(update);
 	struct interval_tree_node *it;
 
 	/* notification is exclusive, but interval is inclusive */
@@ -243,13 +244,14 @@ static int amdgpu_mn_sync_pagetables_gfx(struct hmm_mirror *mirror,
  * necessitates evicting all user-mode queues of the process. The BOs
  * are restorted in amdgpu_mn_invalidate_range_end_hsa.
  */
-static int amdgpu_mn_sync_pagetables_hsa(struct hmm_mirror *mirror,
-			const struct hmm_update *update)
+static int
+amdgpu_mn_sync_pagetables_hsa(struct hmm_mirror *mirror,
+			      const struct mmu_notifier_range *update)
 {
 	struct amdgpu_mn *amn = container_of(mirror, struct amdgpu_mn, mirror);
 	unsigned long start = update->start;
 	unsigned long end = update->end;
-	bool blockable = update->blockable;
+	bool blockable = mmu_notifier_range_blockable(update);
 	struct interval_tree_node *it;
 
 	/* notification is exclusive, but interval is inclusive */
@@ -482,6 +484,5 @@ void amdgpu_hmm_init_range(struct hmm_range *range)
 		range->flags = hmm_range_flags;
 		range->values = hmm_range_values;
 		range->pfn_shift = PAGE_SHIFT;
-		INIT_LIST_HEAD(&range->list);
 	}
 }