[PATCH v12 27/69] mm/mmap: move mmap_region() below do_munmap()

Liam Howlett
2022-07-20T02:20:33Z

Relocation of code for the next commit. There should be no changes here.

Link: https://lkml.kernel.org/r/20220504011345.662299-12-Liam.Howlett@oracle.com
Link: https://lkml.kernel.org/r/20220621204632.3370049-28-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/mmap.c | 492 +++++++++++++++++++++++++++---------------------------
1 file changed, 246 insertions(+), 246 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index 26bb60318066..0cde534a8f9f 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1764,252 +1764,6 @@ static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags)
return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE;
}

-unsigned long mmap_region(struct file *file, unsigned long addr,
- unsigned long len, vm_flags_t vm_flags, unsigned long pgoff,
- struct list_head *uf)
-{
- struct mm_struct *mm = current->mm;
- struct vm_area_struct *vma = NULL;
- struct vm_area_struct *next, *prev, *merge;
- pgoff_t pglen = len >> PAGE_SHIFT;
- unsigned long charged = 0;
- unsigned long end = addr + len;
- unsigned long merge_start = addr, merge_end = end;
- pgoff_t vm_pgoff;
- int error;
- MA_STATE(mas, &mm->mm_mt, addr, end - 1);
-
- /* Check against address space limit. */
- if (!may_expand_vm(mm, vm_flags, len >> PAGE_SHIFT)) {
- unsigned long nr_pages;
-
- /*
- * MAP_FIXED may remove pages of mappings that intersects with
- * requested mapping. Account for the pages it would unmap.
- */
- nr_pages = count_vma_pages_range(mm, addr, end);
-
- if (!may_expand_vm(mm, vm_flags,
- (len >> PAGE_SHIFT) - nr_pages))
- return -ENOMEM;
- }
-
- /* Unmap any existing mapping in the area */
- if (do_munmap(mm, addr, len, uf))
- return -ENOMEM;
-
- /*
- * Private writable mapping: check memory availability
- */
- if (accountable_mapping(file, vm_flags)) {
- charged = len >> PAGE_SHIFT;
- if (security_vm_enough_memory_mm(mm, charged))
- return -ENOMEM;
- vm_flags |= VM_ACCOUNT;
- }
-
- next = mas_next(&mas, ULONG_MAX);
- prev = mas_prev(&mas, 0);
- if (vm_flags & VM_SPECIAL)
- goto cannot_expand;
-
- /* Attempt to expand an old mapping */
- /* Check next */
- if (next && next->vm_start == end && !vma_policy(next) &&
- can_vma_merge_before(next, vm_flags, NULL, file, pgoff+pglen,
- NULL_VM_UFFD_CTX, NULL)) {
- merge_end = next->vm_end;
- vma = next;
- vm_pgoff = next->vm_pgoff - pglen;
- }
-
- /* Check prev */
- if (prev && prev->vm_end == addr && !vma_policy(prev) &&
- (vma ? can_vma_merge_after(prev, vm_flags, vma->anon_vma, file,
- pgoff, vma->vm_userfaultfd_ctx, NULL) :
- can_vma_merge_after(prev, vm_flags, NULL, file, pgoff,
- NULL_VM_UFFD_CTX, NULL))) {
- merge_start = prev->vm_start;
- vma = prev;
- vm_pgoff = prev->vm_pgoff;
- }
-
-
- /* Actually expand, if possible */
- if (vma &&
- !vma_expand(&mas, vma, merge_start, merge_end, vm_pgoff, next)) {
- khugepaged_enter_vma(vma, vm_flags);
- goto expanded;
- }
-
- mas.index = addr;
- mas.last = end - 1;
-cannot_expand:
- /*
- * Determine the object being mapped and call the appropriate
- * specific mapper. the address has already been validated, but
- * not unmapped, but the maps are removed from the list.
- */
- vma = vm_area_alloc(mm);
- if (!vma) {
- error = -ENOMEM;
- goto unacct_error;
- }
-
- vma->vm_start = addr;
- vma->vm_end = end;
- vma->vm_flags = vm_flags;
- vma->vm_page_prot = vm_get_page_prot(vm_flags);
- vma->vm_pgoff = pgoff;
-
- if (file) {
- if (vm_flags & VM_SHARED) {
- error = mapping_map_writable(file->f_mapping);
- if (error)
- goto free_vma;
- }
-
- vma->vm_file = get_file(file);
- error = call_mmap(file, vma);
- if (error)
- goto unmap_and_free_vma;
-
- /* Can addr have changed??
- *
- * Answer: Yes, several device drivers can do it in their
- * f_op->mmap method. -DaveM
- */
- WARN_ON_ONCE(addr != vma->vm_start);
-
- addr = vma->vm_start;
- mas_reset(&mas);
-
- /*
- * If vm_flags changed after call_mmap(), we should try merge
- * vma again as we may succeed this time.
- */
- if (unlikely(vm_flags != vma->vm_flags && prev)) {
- merge = vma_merge(mm, prev, vma->vm_start, vma->vm_end, vma->vm_flags,
- NULL, vma->vm_file, vma->vm_pgoff, NULL, NULL_VM_UFFD_CTX, NULL);
- if (merge) {
- /*
- * ->mmap() can change vma->vm_file and fput
- * the original file. So fput the vma->vm_file
- * here or we would add an extra fput for file
- * and cause general protection fault
- * ultimately.
- */
- fput(vma->vm_file);
- vm_area_free(vma);
- vma = merge;
- /* Update vm_flags to pick up the change. */
- addr = vma->vm_start;
- vm_flags = vma->vm_flags;
- goto unmap_writable;
- }
- }
-
- vm_flags = vma->vm_flags;
- } else if (vm_flags & VM_SHARED) {
- error = shmem_zero_setup(vma);
- if (error)
- goto free_vma;
- } else {
- vma_set_anonymous(vma);
- }
-
- /* Allow architectures to sanity-check the vm_flags */
- if (!arch_validate_flags(vma->vm_flags)) {
- error = -EINVAL;
- if (file)
- goto unmap_and_free_vma;
- else
- goto free_vma;
- }
-
- if (mas_preallocate(&mas, vma, GFP_KERNEL)) {
- error = -ENOMEM;
- if (file)
- goto unmap_and_free_vma;
- else
- goto free_vma;
- }
-
- if (vma->vm_file)
- i_mmap_lock_write(vma->vm_file->f_mapping);
-
- vma_mas_store(vma, &mas);
- __vma_link_list(mm, vma, prev);
- mm->map_count++;
- if (vma->vm_file) {
- if (vma->vm_flags & VM_SHARED)
- mapping_allow_writable(vma->vm_file->f_mapping);
-
- flush_dcache_mmap_lock(vma->vm_file->f_mapping);
- vma_interval_tree_insert(vma, &vma->vm_file->f_mapping->i_mmap);
- flush_dcache_mmap_unlock(vma->vm_file->f_mapping);
- i_mmap_unlock_write(vma->vm_file->f_mapping);
- }
-
- /*
- * vma_merge() calls khugepaged_enter_vma() either, the below
- * call covers the non-merge case.
- */
- khugepaged_enter_vma(vma, vma->vm_flags);
-
- /* Once vma denies write, undo our temporary denial count */
-unmap_writable:
- if (file && vm_flags & VM_SHARED)
- mapping_unmap_writable(file->f_mapping);
- file = vma->vm_file;
-expanded:
- perf_event_mmap(vma);
-
- vm_stat_account(mm, vm_flags, len >> PAGE_SHIFT);
- if (vm_flags & VM_LOCKED) {
- if ((vm_flags & VM_SPECIAL) || vma_is_dax(vma) ||
- is_vm_hugetlb_page(vma) ||
- vma == get_gate_vma(current->mm))
- vma->vm_flags &= VM_LOCKED_CLEAR_MASK;
- else
- mm->locked_vm += (len >> PAGE_SHIFT);
- }
-
- if (file)
- uprobe_mmap(vma);
-
- /*
- * New (or expanded) vma always get soft dirty status.
- * Otherwise user-space soft-dirty page tracker won't
- * be able to distinguish situation when vma area unmapped,
- * then new mapped in-place (which must be aimed as
- * a completely new data area).
- */
- vma->vm_flags |= VM_SOFTDIRTY;
-
- vma_set_page_prot(vma);
-
- validate_mm(mm);
- return addr;
-
-unmap_and_free_vma:
- fput(vma->vm_file);
- vma->vm_file = NULL;
-
- /* Undo any partial mapping done by a device driver. */
- unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
- charged = 0;
- if (vm_flags & VM_SHARED)
- mapping_unmap_writable(file->f_mapping);
-free_vma:
- vm_area_free(vma);
-unacct_error:
- if (charged)
- vm_unacct_memory(charged);
- validate_mm(mm);
- return error;
-}
-
/**
* unmapped_area() - Find an area between the low_limit and the high_limit with
* the correct alignment and offset, all from @info. Note: current->mm is used
@@ -2883,6 +2637,252 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
return __do_munmap(mm, start, len, uf, false);
}

+unsigned long mmap_region(struct file *file, unsigned long addr,
+ unsigned long len, vm_flags_t vm_flags, unsigned long pgoff,
+ struct list_head *uf)
+{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma = NULL;
+ struct vm_area_struct *next, *prev, *merge;
+ pgoff_t pglen = len >> PAGE_SHIFT;
+ unsigned long charged = 0;
+ unsigned long end = addr + len;
+ unsigned long merge_start = addr, merge_end = end;
+ pgoff_t vm_pgoff;
+ int error;
+ MA_STATE(mas, &mm->mm_mt, addr, end - 1);
+
+ /* Check against address space limit. */
+ if (!may_expand_vm(mm, vm_flags, len >> PAGE_SHIFT)) {
+ unsigned long nr_pages;
+
+ /*
+ * MAP_FIXED may remove pages of mappings that intersects with
+ * requested mapping. Account for the pages it would unmap.
+ */
+ nr_pages = count_vma_pages_range(mm, addr, end);
+
+ if (!may_expand_vm(mm, vm_flags,
+ (len >> PAGE_SHIFT) - nr_pages))
+ return -ENOMEM;
+ }
+
+ /* Unmap any existing mapping in the area */
+ if (do_munmap(mm, addr, len, uf))
+ return -ENOMEM;
+
+ /*
+ * Private writable mapping: check memory availability
+ */
+ if (accountable_mapping(file, vm_flags)) {
+ charged = len >> PAGE_SHIFT;
+ if (security_vm_enough_memory_mm(mm, charged))
+ return -ENOMEM;
+ vm_flags |= VM_ACCOUNT;
+ }
+
+ next = mas_next(&mas, ULONG_MAX);
+ prev = mas_prev(&mas, 0);
+ if (vm_flags & VM_SPECIAL)
+ goto cannot_expand;
+
+ /* Attempt to expand an old mapping */
+ /* Check next */
+ if (next && next->vm_start == end && !vma_policy(next) &&
+ can_vma_merge_before(next, vm_flags, NULL, file, pgoff+pglen,
+ NULL_VM_UFFD_CTX, NULL)) {
+ merge_end = next->vm_end;
+ vma = next;
+ vm_pgoff = next->vm_pgoff - pglen;
+ }
+
+ /* Check prev */
+ if (prev && prev->vm_end == addr && !vma_policy(prev) &&
+ (vma ? can_vma_merge_after(prev, vm_flags, vma->anon_vma, file,
+ pgoff, vma->vm_userfaultfd_ctx, NULL) :
+ can_vma_merge_after(prev, vm_flags, NULL, file, pgoff,
+ NULL_VM_UFFD_CTX, NULL))) {
+ merge_start = prev->vm_start;
+ vma = prev;
+ vm_pgoff = prev->vm_pgoff;
+ }
+
+
+ /* Actually expand, if possible */
+ if (vma &&
+ !vma_expand(&mas, vma, merge_start, merge_end, vm_pgoff, next)) {
+ khugepaged_enter_vma(vma, vm_flags);
+ goto expanded;
+ }
+
+ mas.index = addr;
+ mas.last = end - 1;
+cannot_expand:
+ /*
+ * Determine the object being mapped and call the appropriate
+ * specific mapper. the address has already been validated, but
+ * not unmapped, but the maps are removed from the list.
+ */
+ vma = vm_area_alloc(mm);
+ if (!vma) {
+ error = -ENOMEM;
+ goto unacct_error;
+ }
+
+ vma->vm_start = addr;
+ vma->vm_end = end;
+ vma->vm_flags = vm_flags;
+ vma->vm_page_prot = vm_get_page_prot(vm_flags);
+ vma->vm_pgoff = pgoff;
+
+ if (file) {
+ if (vm_flags & VM_SHARED) {
+ error = mapping_map_writable(file->f_mapping);
+ if (error)
+ goto free_vma;
+ }
+
+ vma->vm_file = get_file(file);
+ error = call_mmap(file, vma);
+ if (error)
+ goto unmap_and_free_vma;
+
+ /* Can addr have changed??
+ *
+ * Answer: Yes, several device drivers can do it in their
+ * f_op->mmap method. -DaveM
+ */
+ WARN_ON_ONCE(addr != vma->vm_start);
+
+ addr = vma->vm_start;
+ mas_reset(&mas);
+
+ /*
+ * If vm_flags changed after call_mmap(), we should try merge
+ * vma again as we may succeed this time.
+ */
+ if (unlikely(vm_flags != vma->vm_flags && prev)) {
+ merge = vma_merge(mm, prev, vma->vm_start, vma->vm_end, vma->vm_flags,
+ NULL, vma->vm_file, vma->vm_pgoff, NULL, NULL_VM_UFFD_CTX, NULL);
+ if (merge) {
+ /*
+ * ->mmap() can change vma->vm_file and fput
+ * the original file. So fput the vma->vm_file
+ * here or we would add an extra fput for file
+ * and cause general protection fault
+ * ultimately.
+ */
+ fput(vma->vm_file);
+ vm_area_free(vma);
+ vma = merge;
+ /* Update vm_flags to pick up the change. */
+ addr = vma->vm_start;
+ vm_flags = vma->vm_flags;
+ goto unmap_writable;
+ }
+ }
+
+ vm_flags = vma->vm_flags;
+ } else if (vm_flags & VM_SHARED) {
+ error = shmem_zero_setup(vma);
+ if (error)
+ goto free_vma;
+ } else {
+ vma_set_anonymous(vma);
+ }
+
+ /* Allow architectures to sanity-check the vm_flags */
+ if (!arch_validate_flags(vma->vm_flags)) {
+ error = -EINVAL;
+ if (file)
+ goto unmap_and_free_vma;
+ else
+ goto free_vma;
+ }
+
+ if (mas_preallocate(&mas, vma, GFP_KERNEL)) {
+ error = -ENOMEM;
+ if (file)
+ goto unmap_and_free_vma;
+ else
+ goto free_vma;
+ }
+
+ if (vma->vm_file)
+ i_mmap_lock_write(vma->vm_file->f_mapping);
+
+ vma_mas_store(vma, &mas);
+ __vma_link_list(mm, vma, prev);
+ mm->map_count++;
+ if (vma->vm_file) {
+ if (vma->vm_flags & VM_SHARED)
+ mapping_allow_writable(vma->vm_file->f_mapping);
+
+ flush_dcache_mmap_lock(vma->vm_file->f_mapping);
+ vma_interval_tree_insert(vma, &vma->vm_file->f_mapping->i_mmap);
+ flush_dcache_mmap_unlock(vma->vm_file->f_mapping);
+ i_mmap_unlock_write(vma->vm_file->f_mapping);
+ }
+
+ /*
+ * vma_merge() calls khugepaged_enter_vma() either, the below
+ * call covers the non-merge case.
+ */
+ khugepaged_enter_vma(vma, vma->vm_flags);
+
+ /* Once vma denies write, undo our temporary denial count */
+unmap_writable:
+ if (file && vm_flags & VM_SHARED)
+ mapping_unmap_writable(file->f_mapping);
+ file = vma->vm_file;
+expanded:
+ perf_event_mmap(vma);
+
+ vm_stat_account(mm, vm_flags, len >> PAGE_SHIFT);
+ if (vm_flags & VM_LOCKED) {
+ if ((vm_flags & VM_SPECIAL) || vma_is_dax(vma) ||
+ is_vm_hugetlb_page(vma) ||
+ vma == get_gate_vma(current->mm))
+ vma->vm_flags &= VM_LOCKED_CLEAR_MASK;
+ else
+ mm->locked_vm += (len >> PAGE_SHIFT);
+ }
+
+ if (file)
+ uprobe_mmap(vma);
+
+ /*
+ * New (or expanded) vma always get soft dirty status.
+ * Otherwise user-space soft-dirty page tracker won't
+ * be able to distinguish situation when vma area unmapped,
+ * then new mapped in-place (which must be aimed as
+ * a completely new data area).
+ */
+ vma->vm_flags |= VM_SOFTDIRTY;
+
+ vma_set_page_prot(vma);
+
+ validate_mm(mm);
+ return addr;
+
+unmap_and_free_vma:
+ fput(vma->vm_file);
+ vma->vm_file = NULL;
+
+ /* Undo any partial mapping done by a device driver. */
+ unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
+ charged = 0;
+ if (vm_flags & VM_SHARED)
+ mapping_unmap_writable(file->f_mapping);
+free_vma:
+ vm_area_free(vma);
+unacct_error:
+ if (charged)
+ vm_unacct_memory(charged);
+ validate_mm(mm);
+ return error;
+}
+
static int __vm_munmap(unsigned long start, size_t len, bool downgrade)
{
int ret;
--
2.35.1