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mm: isolate mmap internal logic to mm/vma.c

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In previous commits we effected improvements to the mmap() logic in
mmap_region() and its newly introduced internal implementation function
__mmap_region().

However as these changes are intended to be backported, we kept the delta
as small as is possible and made as few changes as possible to the newly
introduced mm/vma.* files.

Take the opportunity to move this logic to mm/vma.c which not only
isolates it, but also makes it available for later userland testing which
can help us catch such logic errors far earlier.

Link: https://lkml.kernel.org/r/93fc2c3aa37dd30590b7e4ee067dfd832007bf7e.1729858176.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Lorenzo Stoakes 2024-10-25 13:26:24 +01:00 committed by Andrew Morton
parent c14f8046cd
commit 52956b0d7f
4 changed files with 329 additions and 330 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

234
mm/mmap.c
View file

@ -577,22 +577,6 @@ SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
} }
#endif /* __ARCH_WANT_SYS_OLD_MMAP */ #endif /* __ARCH_WANT_SYS_OLD_MMAP */
/*
* We account for memory if it's a private writeable mapping,
* not hugepages and VM_NORESERVE wasn't set.
*/
static inline bool accountable_mapping(struct file *file, vm_flags_t vm_flags)
{
/*
* hugetlb has its own accounting separate from the core VM
* VM_HUGETLB may not be set yet so we cannot check for that flag.
*/
if (file && is_file_hugepages(file))
return false;
return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE;
}
/** /**
* unmapped_area() - Find an area between the low_limit and the high_limit with * 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 * the correct alignment and offset, all from @info. Note: current->mm is used
@ -1362,224 +1346,6 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
return do_vmi_munmap(&vmi, mm, start, len, uf, false); return do_vmi_munmap(&vmi, mm, start, len, uf, false);
} }
static 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;
pgoff_t pglen = PHYS_PFN(len);
unsigned long charged = 0;
struct vma_munmap_struct vms;
struct ma_state mas_detach;
struct maple_tree mt_detach;
unsigned long end = addr + len;
int error;
VMA_ITERATOR(vmi, mm, addr);
VMG_STATE(vmg, mm, &vmi, addr, end, vm_flags, pgoff);
vmg.file = file;
/* Find the first overlapping VMA */
vma = vma_find(&vmi, end);
init_vma_munmap(&vms, &vmi, vma, addr, end, uf, /* unlock = */ false);
if (vma) {
mt_init_flags(&mt_detach, vmi.mas.tree->ma_flags & MT_FLAGS_LOCK_MASK);
mt_on_stack(mt_detach);
mas_init(&mas_detach, &mt_detach, /* addr = */ 0);
/* Prepare to unmap any existing mapping in the area */
error = vms_gather_munmap_vmas(&vms, &mas_detach);
if (error)
goto gather_failed;
vmg.next = vms.next;
vmg.prev = vms.prev;
vma = NULL;
} else {
vmg.next = vma_iter_next_rewind(&vmi, &vmg.prev);
}
/* Check against address space limit. */
if (!may_expand_vm(mm, vm_flags, pglen - vms.nr_pages)) {
error = -ENOMEM;
goto abort_munmap;
}
/*
* Private writable mapping: check memory availability
*/
if (accountable_mapping(file, vm_flags)) {
charged = pglen;
charged -= vms.nr_accounted;
if (charged) {
error = security_vm_enough_memory_mm(mm, charged);
if (error)
goto abort_munmap;
}
vms.nr_accounted = 0;
vm_flags |= VM_ACCOUNT;
vmg.flags = vm_flags;
}
/*
* clear PTEs while the vma is still in the tree so that rmap
* cannot race with the freeing later in the truncate scenario.
* This is also needed for mmap_file(), which is why vm_ops
* close function is called.
*/
vms_clean_up_area(&vms, &mas_detach);
vma = vma_merge_new_range(&vmg);
if (vma)
goto expanded;
/*
* 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_iter_config(&vmi, addr, end);
vma_set_range(vma, addr, end, pgoff);
vm_flags_init(vma, vm_flags);
vma->vm_page_prot = vm_get_page_prot(vm_flags);
if (vma_iter_prealloc(&vmi, vma)) {
error = -ENOMEM;
goto free_vma;
}
if (file) {
vma->vm_file = get_file(file);
error = mmap_file(file, vma);
if (error)
goto unmap_and_free_file_vma;
/* Drivers cannot alter the address of the VMA. */
WARN_ON_ONCE(addr != vma->vm_start);
/*
* Drivers should not permit writability when previously it was
* disallowed.
*/
VM_WARN_ON_ONCE(vm_flags != vma->vm_flags &&
!(vm_flags & VM_MAYWRITE) &&
(vma->vm_flags & VM_MAYWRITE));
vma_iter_config(&vmi, addr, end);
/*
* If vm_flags changed after mmap_file(), we should try merge
* vma again as we may succeed this time.
*/
if (unlikely(vm_flags != vma->vm_flags && vmg.prev)) {
struct vm_area_struct *merge;
vmg.flags = vma->vm_flags;
/* If this fails, state is reset ready for a reattempt. */
merge = vma_merge_new_range(&vmg);
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. */
vm_flags = vma->vm_flags;
goto file_expanded;
}
vma_iter_config(&vmi, addr, end);
}
vm_flags = vma->vm_flags;
} else if (vm_flags & VM_SHARED) {
error = shmem_zero_setup(vma);
if (error)
goto free_iter_vma;
} else {
vma_set_anonymous(vma);
}
#ifdef CONFIG_SPARC64
/* TODO: Fix SPARC ADI! */
WARN_ON_ONCE(!arch_validate_flags(vm_flags));
#endif
/* Lock the VMA since it is modified after insertion into VMA tree */
vma_start_write(vma);
vma_iter_store(&vmi, vma);
mm->map_count++;
vma_link_file(vma);
/*
* vma_merge_new_range() calls khugepaged_enter_vma() too, the below
* call covers the non-merge case.
*/
khugepaged_enter_vma(vma, vma->vm_flags);
file_expanded:
file = vma->vm_file;
ksm_add_vma(vma);
expanded:
perf_event_mmap(vma);
/* Unmap any existing mapping in the area */
vms_complete_munmap_vmas(&vms, &mas_detach);
vm_stat_account(mm, vm_flags, pglen);
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))
vm_flags_clear(vma, VM_LOCKED_MASK);
else
mm->locked_vm += pglen;
}
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).
*/
vm_flags_set(vma, VM_SOFTDIRTY);
vma_set_page_prot(vma);
return addr;
unmap_and_free_file_vma:
fput(vma->vm_file);
vma->vm_file = NULL;
vma_iter_set(&vmi, vma->vm_end);
/* Undo any partial mapping done by a device driver. */
unmap_region(&vmi.mas, vma, vmg.prev, vmg.next);
free_iter_vma:
vma_iter_free(&vmi);
free_vma:
vm_area_free(vma);
unacct_error:
if (charged)
vm_unacct_memory(charged);
abort_munmap:
vms_abort_munmap_vmas(&vms, &mas_detach);
gather_failed:
return error;
}
unsigned long mmap_region(struct file *file, unsigned long addr, unsigned long mmap_region(struct file *file, unsigned long addr,
unsigned long len, vm_flags_t vm_flags, unsigned long pgoff, unsigned long len, vm_flags_t vm_flags, unsigned long pgoff,
struct list_head *uf) struct list_head *uf)

323
mm/vma.c
View file

@ -1103,7 +1103,7 @@ static inline void vms_clear_ptes(struct vma_munmap_struct *vms,
vms->clear_ptes = false; vms->clear_ptes = false;
} }
void vms_clean_up_area(struct vma_munmap_struct *vms, static void vms_clean_up_area(struct vma_munmap_struct *vms,
struct ma_state *mas_detach) struct ma_state *mas_detach)
{ {
struct vm_area_struct *vma; struct vm_area_struct *vma;
@ -1126,7 +1126,7 @@ void vms_clean_up_area(struct vma_munmap_struct *vms,
* used for the munmap() and may downgrade the lock - if requested. Everything * used for the munmap() and may downgrade the lock - if requested. Everything
* needed to be done once the vma maple tree is updated. * needed to be done once the vma maple tree is updated.
*/ */
void vms_complete_munmap_vmas(struct vma_munmap_struct *vms, static void vms_complete_munmap_vmas(struct vma_munmap_struct *vms,
struct ma_state *mas_detach) struct ma_state *mas_detach)
{ {
struct vm_area_struct *vma; struct vm_area_struct *vma;
@ -1167,6 +1167,23 @@ void vms_complete_munmap_vmas(struct vma_munmap_struct *vms,
__mt_destroy(mas_detach->tree); __mt_destroy(mas_detach->tree);
} }
/*
* reattach_vmas() - Undo any munmap work and free resources
* @mas_detach: The maple state with the detached maple tree
*
* Reattach any detached vmas and free up the maple tree used to track the vmas.
*/
static void reattach_vmas(struct ma_state *mas_detach)
{
struct vm_area_struct *vma;
mas_set(mas_detach, 0);
mas_for_each(mas_detach, vma, ULONG_MAX)
vma_mark_detached(vma, false);
__mt_destroy(mas_detach->tree);
}
/* /*
* vms_gather_munmap_vmas() - Put all VMAs within a range into a maple tree * vms_gather_munmap_vmas() - Put all VMAs within a range into a maple tree
* for removal at a later date. Handles splitting first and last if necessary * for removal at a later date. Handles splitting first and last if necessary
@ -1177,7 +1194,7 @@ void vms_complete_munmap_vmas(struct vma_munmap_struct *vms,
* *
* Return: 0 on success, error otherwise * Return: 0 on success, error otherwise
*/ */
int vms_gather_munmap_vmas(struct vma_munmap_struct *vms, static int vms_gather_munmap_vmas(struct vma_munmap_struct *vms,
struct ma_state *mas_detach) struct ma_state *mas_detach)
{ {
struct vm_area_struct *next = NULL; struct vm_area_struct *next = NULL;
@ -1315,6 +1332,39 @@ int vms_gather_munmap_vmas(struct vma_munmap_struct *vms,
return error; return error;
} }
/*
* init_vma_munmap() - Initializer wrapper for vma_munmap_struct
* @vms: The vma munmap struct
* @vmi: The vma iterator
* @vma: The first vm_area_struct to munmap
* @start: The aligned start address to munmap
* @end: The aligned end address to munmap
* @uf: The userfaultfd list_head
* @unlock: Unlock after the operation. Only unlocked on success
*/
static void init_vma_munmap(struct vma_munmap_struct *vms,
struct vma_iterator *vmi, struct vm_area_struct *vma,
unsigned long start, unsigned long end, struct list_head *uf,
bool unlock)
{
vms->vmi = vmi;
vms->vma = vma;
if (vma) {
vms->start = start;
vms->end = end;
} else {
vms->start = vms->end = 0;
}
vms->unlock = unlock;
vms->uf = uf;
vms->vma_count = 0;
vms->nr_pages = vms->locked_vm = vms->nr_accounted = 0;
vms->exec_vm = vms->stack_vm = vms->data_vm = 0;
vms->unmap_start = FIRST_USER_ADDRESS;
vms->unmap_end = USER_PGTABLES_CEILING;
vms->clear_ptes = false;
}
/* /*
* do_vmi_align_munmap() - munmap the aligned region from @start to @end. * do_vmi_align_munmap() - munmap the aligned region from @start to @end.
* @vmi: The vma iterator * @vmi: The vma iterator
@ -2069,3 +2119,270 @@ void mm_drop_all_locks(struct mm_struct *mm)
mutex_unlock(&mm_all_locks_mutex); mutex_unlock(&mm_all_locks_mutex);
} }
/*
* We account for memory if it's a private writeable mapping,
* not hugepages and VM_NORESERVE wasn't set.
*/
static bool accountable_mapping(struct file *file, vm_flags_t vm_flags)
{
/*
* hugetlb has its own accounting separate from the core VM
* VM_HUGETLB may not be set yet so we cannot check for that flag.
*/
if (file && is_file_hugepages(file))
return false;
return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE;
}
/*
* vms_abort_munmap_vmas() - Undo as much as possible from an aborted munmap()
* operation.
* @vms: The vma unmap structure
* @mas_detach: The maple state with the detached maple tree
*
* Reattach any detached vmas, free up the maple tree used to track the vmas.
* If that's not possible because the ptes are cleared (and vm_ops->closed() may
* have been called), then a NULL is written over the vmas and the vmas are
* removed (munmap() completed).
*/
static void vms_abort_munmap_vmas(struct vma_munmap_struct *vms,
struct ma_state *mas_detach)
{
struct ma_state *mas = &vms->vmi->mas;
if (!vms->nr_pages)
return;
if (vms->clear_ptes)
return reattach_vmas(mas_detach);
/*
* Aborting cannot just call the vm_ops open() because they are often
* not symmetrical and state data has been lost. Resort to the old
* failure method of leaving a gap where the MAP_FIXED mapping failed.
*/
mas_set_range(mas, vms->start, vms->end - 1);
mas_store_gfp(mas, NULL, GFP_KERNEL|__GFP_NOFAIL);
/* Clean up the insertion of the unfortunate gap */
vms_complete_munmap_vmas(vms, mas_detach);
}
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;
pgoff_t pglen = PHYS_PFN(len);
unsigned long charged = 0;
struct vma_munmap_struct vms;
struct ma_state mas_detach;
struct maple_tree mt_detach;
unsigned long end = addr + len;
int error;
VMA_ITERATOR(vmi, mm, addr);
VMG_STATE(vmg, mm, &vmi, addr, end, vm_flags, pgoff);
vmg.file = file;
/* Find the first overlapping VMA */
vma = vma_find(&vmi, end);
init_vma_munmap(&vms, &vmi, vma, addr, end, uf, /* unlock = */ false);
if (vma) {
mt_init_flags(&mt_detach, vmi.mas.tree->ma_flags & MT_FLAGS_LOCK_MASK);
mt_on_stack(mt_detach);
mas_init(&mas_detach, &mt_detach, /* addr = */ 0);
/* Prepare to unmap any existing mapping in the area */
error = vms_gather_munmap_vmas(&vms, &mas_detach);
if (error)
goto gather_failed;
vmg.next = vms.next;
vmg.prev = vms.prev;
vma = NULL;
} else {
vmg.next = vma_iter_next_rewind(&vmi, &vmg.prev);
}
/* Check against address space limit. */
if (!may_expand_vm(mm, vm_flags, pglen - vms.nr_pages)) {
error = -ENOMEM;
goto abort_munmap;
}
/*
* Private writable mapping: check memory availability
*/
if (accountable_mapping(file, vm_flags)) {
charged = pglen;
charged -= vms.nr_accounted;
if (charged) {
error = security_vm_enough_memory_mm(mm, charged);
if (error)
goto abort_munmap;
}
vms.nr_accounted = 0;
vm_flags |= VM_ACCOUNT;
vmg.flags = vm_flags;
}
/*
* clear PTEs while the vma is still in the tree so that rmap
* cannot race with the freeing later in the truncate scenario.
* This is also needed for mmap_file(), which is why vm_ops
* close function is called.
*/
vms_clean_up_area(&vms, &mas_detach);
vma = vma_merge_new_range(&vmg);
if (vma)
goto expanded;
/*
* 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_iter_config(&vmi, addr, end);
vma_set_range(vma, addr, end, pgoff);
vm_flags_init(vma, vm_flags);
vma->vm_page_prot = vm_get_page_prot(vm_flags);
if (vma_iter_prealloc(&vmi, vma)) {
error = -ENOMEM;
goto free_vma;
}
if (file) {
vma->vm_file = get_file(file);
error = mmap_file(file, vma);
if (error)
goto unmap_and_free_file_vma;
/* Drivers cannot alter the address of the VMA. */
WARN_ON_ONCE(addr != vma->vm_start);
/*
* Drivers should not permit writability when previously it was
* disallowed.
*/
VM_WARN_ON_ONCE(vm_flags != vma->vm_flags &&
!(vm_flags & VM_MAYWRITE) &&
(vma->vm_flags & VM_MAYWRITE));
vma_iter_config(&vmi, addr, end);
/*
* If vm_flags changed after mmap_file(), we should try merge
* vma again as we may succeed this time.
*/
if (unlikely(vm_flags != vma->vm_flags && vmg.prev)) {
struct vm_area_struct *merge;
vmg.flags = vma->vm_flags;
/* If this fails, state is reset ready for a reattempt. */
merge = vma_merge_new_range(&vmg);
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. */
vm_flags = vma->vm_flags;
goto file_expanded;
}
vma_iter_config(&vmi, addr, end);
}
vm_flags = vma->vm_flags;
} else if (vm_flags & VM_SHARED) {
error = shmem_zero_setup(vma);
if (error)
goto free_iter_vma;
} else {
vma_set_anonymous(vma);
}
#ifdef CONFIG_SPARC64
/* TODO: Fix SPARC ADI! */
WARN_ON_ONCE(!arch_validate_flags(vm_flags));
#endif
/* Lock the VMA since it is modified after insertion into VMA tree */
vma_start_write(vma);
vma_iter_store(&vmi, vma);
mm->map_count++;
vma_link_file(vma);
/*
* vma_merge_new_range() calls khugepaged_enter_vma() too, the below
* call covers the non-merge case.
*/
khugepaged_enter_vma(vma, vma->vm_flags);
file_expanded:
file = vma->vm_file;
ksm_add_vma(vma);
expanded:
perf_event_mmap(vma);
/* Unmap any existing mapping in the area */
vms_complete_munmap_vmas(&vms, &mas_detach);
vm_stat_account(mm, vm_flags, pglen);
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))
vm_flags_clear(vma, VM_LOCKED_MASK);
else
mm->locked_vm += pglen;
}
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).
*/
vm_flags_set(vma, VM_SOFTDIRTY);
vma_set_page_prot(vma);
return addr;
unmap_and_free_file_vma:
fput(vma->vm_file);
vma->vm_file = NULL;
vma_iter_set(&vmi, vma->vm_end);
/* Undo any partial mapping done by a device driver. */
unmap_region(&vmi.mas, vma, vmg.prev, vmg.next);
free_iter_vma:
vma_iter_free(&vmi);
free_vma:
vm_area_free(vma);
unacct_error:
if (charged)
vm_unacct_memory(charged);
abort_munmap:
vms_abort_munmap_vmas(&vms, &mas_detach);
gather_failed:
return error;
}

97
mm/vma.h
View file

@ -165,99 +165,6 @@ static inline int vma_iter_store_gfp(struct vma_iterator *vmi,
return 0; return 0;
} }
#ifdef CONFIG_MMU
/*
* init_vma_munmap() - Initializer wrapper for vma_munmap_struct
* @vms: The vma munmap struct
* @vmi: The vma iterator
* @vma: The first vm_area_struct to munmap
* @start: The aligned start address to munmap
* @end: The aligned end address to munmap
* @uf: The userfaultfd list_head
* @unlock: Unlock after the operation. Only unlocked on success
*/
static inline void init_vma_munmap(struct vma_munmap_struct *vms,
struct vma_iterator *vmi, struct vm_area_struct *vma,
unsigned long start, unsigned long end, struct list_head *uf,
bool unlock)
{
vms->vmi = vmi;
vms->vma = vma;
if (vma) {
vms->start = start;
vms->end = end;
} else {
vms->start = vms->end = 0;
}
vms->unlock = unlock;
vms->uf = uf;
vms->vma_count = 0;
vms->nr_pages = vms->locked_vm = vms->nr_accounted = 0;
vms->exec_vm = vms->stack_vm = vms->data_vm = 0;
vms->unmap_start = FIRST_USER_ADDRESS;
vms->unmap_end = USER_PGTABLES_CEILING;
vms->clear_ptes = false;
}
#endif
int vms_gather_munmap_vmas(struct vma_munmap_struct *vms,
struct ma_state *mas_detach);
void vms_complete_munmap_vmas(struct vma_munmap_struct *vms,
struct ma_state *mas_detach);
void vms_clean_up_area(struct vma_munmap_struct *vms,
struct ma_state *mas_detach);
/*
* reattach_vmas() - Undo any munmap work and free resources
* @mas_detach: The maple state with the detached maple tree
*
* Reattach any detached vmas and free up the maple tree used to track the vmas.
*/
static inline void reattach_vmas(struct ma_state *mas_detach)
{
struct vm_area_struct *vma;
mas_set(mas_detach, 0);
mas_for_each(mas_detach, vma, ULONG_MAX)
vma_mark_detached(vma, false);
__mt_destroy(mas_detach->tree);
}
/*
* vms_abort_munmap_vmas() - Undo as much as possible from an aborted munmap()
* operation.
* @vms: The vma unmap structure
* @mas_detach: The maple state with the detached maple tree
*
* Reattach any detached vmas, free up the maple tree used to track the vmas.
* If that's not possible because the ptes are cleared (and vm_ops->closed() may
* have been called), then a NULL is written over the vmas and the vmas are
* removed (munmap() completed).
*/
static inline void vms_abort_munmap_vmas(struct vma_munmap_struct *vms,
struct ma_state *mas_detach)
{
struct ma_state *mas = &vms->vmi->mas;
if (!vms->nr_pages)
return;
if (vms->clear_ptes)
return reattach_vmas(mas_detach);
/*
* Aborting cannot just call the vm_ops open() because they are often
* not symmetrical and state data has been lost. Resort to the old
* failure method of leaving a gap where the MAP_FIXED mapping failed.
*/
mas_set_range(mas, vms->start, vms->end - 1);
mas_store_gfp(mas, NULL, GFP_KERNEL|__GFP_NOFAIL);
/* Clean up the insertion of the unfortunate gap */
vms_complete_munmap_vmas(vms, mas_detach);
}
int int
do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
struct mm_struct *mm, unsigned long start, struct mm_struct *mm, unsigned long start,
@ -336,6 +243,10 @@ bool vma_wants_writenotify(struct vm_area_struct *vma, pgprot_t vm_page_prot);
int mm_take_all_locks(struct mm_struct *mm); int mm_take_all_locks(struct mm_struct *mm);
void mm_drop_all_locks(struct mm_struct *mm); void mm_drop_all_locks(struct mm_struct *mm);
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);
static inline bool vma_wants_manual_pte_write_upgrade(struct vm_area_struct *vma) static inline bool vma_wants_manual_pte_write_upgrade(struct vm_area_struct *vma)
{ {
/* /*

5
mm/vma_internal.h
View file

@ -17,8 +17,10 @@
#include <linux/file.h> #include <linux/file.h>
#include <linux/fs.h> #include <linux/fs.h>
#include <linux/huge_mm.h> #include <linux/huge_mm.h>
#include <linux/hugetlb.h>
#include <linux/hugetlb_inline.h> #include <linux/hugetlb_inline.h>
#include <linux/kernel.h> #include <linux/kernel.h>
#include <linux/ksm.h>
#include <linux/khugepaged.h> #include <linux/khugepaged.h>
#include <linux/list.h> #include <linux/list.h>
#include <linux/maple_tree.h> #include <linux/maple_tree.h>
@ -32,11 +34,14 @@
#include <linux/mmu_context.h> #include <linux/mmu_context.h>
#include <linux/mutex.h> #include <linux/mutex.h>
#include <linux/pagemap.h> #include <linux/pagemap.h>
#include <linux/perf_event.h>
#include <linux/pfn.h> #include <linux/pfn.h>
#include <linux/rcupdate.h> #include <linux/rcupdate.h>
#include <linux/rmap.h> #include <linux/rmap.h>
#include <linux/rwsem.h> #include <linux/rwsem.h>
#include <linux/sched/signal.h> #include <linux/sched/signal.h>
#include <linux/security.h>
#include <linux/shmem_fs.h>
#include <linux/swap.h> #include <linux/swap.h>
#include <linux/uprobes.h> #include <linux/uprobes.h>
#include <linux/userfaultfd_k.h> #include <linux/userfaultfd_k.h>