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mmap: change do_mas_munmap and do_mas_aligned_munmap() to use vma iterator

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Start passing the vma iterator through the mm code.  This will allow for
reuse of the state and cleaner invalidation if necessary.

Link: https://lkml.kernel.org/r/20230120162650.984577-13-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Liam R. Howlett 2023-01-20 11:26:13 -05:00 committed by Andrew Morton
parent 0378c0a0e9
commit 183654ce26
3 changed files with 39 additions and 46 deletions
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2
include/linux/mm.h
View file

@ -2905,7 +2905,7 @@ extern unsigned long mmap_region(struct file *file, unsigned long addr,
extern unsigned long do_mmap(struct file *file, unsigned long addr,
unsigned long len, unsigned long prot, unsigned long flags,
unsigned long pgoff, unsigned long *populate, struct list_head *uf);
extern int do_mas_munmap(struct ma_state *mas, struct mm_struct *mm,
extern int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm,
unsigned long start, size_t len, struct list_head *uf,
bool downgrade);
extern int do_munmap(struct mm_struct *, unsigned long, size_t,

77
mm/mmap.c
View file

@ -2305,8 +2305,8 @@ static inline int munmap_sidetree(struct vm_area_struct *vma,
}
/*
* do_mas_align_munmap() - munmap the aligned region from @start to @end.
* @mas: The maple_state, ideally set up to alter the correct tree location.
* do_vmi_align_munmap() - munmap the aligned region from @start to @end.
* @vmi: The vma iterator
* @vma: The starting vm_area_struct
* @mm: The mm_struct
* @start: The aligned start address to munmap.
@ -2317,7 +2317,7 @@ static inline int munmap_sidetree(struct vm_area_struct *vma,
* If @downgrade is true, check return code for potential release of the lock.
*/
static int
do_mas_align_munmap(struct ma_state *mas, 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,
unsigned long end, struct list_head *uf, bool downgrade)
{
@ -2329,7 +2329,6 @@ do_mas_align_munmap(struct ma_state *mas, struct vm_area_struct *vma,
mt_init_flags(&mt_detach, MT_FLAGS_LOCK_EXTERN);
mt_set_external_lock(&mt_detach, &mm->mmap_lock);
mas->last = end - 1;
/*
* If we need to split any vma, do it now to save pain later.
*
@ -2349,27 +2348,23 @@ do_mas_align_munmap(struct ma_state *mas, struct vm_area_struct *vma,
if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count)
goto map_count_exceeded;
/*
* mas_pause() is not needed since mas->index needs to be set
* differently than vma->vm_end anyways.
*/
error = __split_vma(mm, vma, start, 0);
if (error)
goto start_split_failed;
mas_set(mas, start);
vma = mas_walk(mas);
vma_iter_set(vmi, start);
vma = vma_find(vmi, end);
}
prev = mas_prev(mas, 0);
prev = vma_prev(vmi);
if (unlikely((!prev)))
mas_set(mas, start);
vma_iter_set(vmi, start);
/*
* Detach a range of VMAs from the mm. Using next as a temp variable as
* it is always overwritten.
*/
mas_for_each(mas, next, end - 1) {
for_each_vma_range(*vmi, next, end) {
/* Does it split the end? */
if (next->vm_end > end) {
struct vm_area_struct *split;
@ -2378,8 +2373,8 @@ do_mas_align_munmap(struct ma_state *mas, struct vm_area_struct *vma,
if (error)
goto end_split_failed;
mas_set(mas, end);
split = mas_prev(mas, 0);
vma_iter_set(vmi, end);
split = vma_prev(vmi);
error = munmap_sidetree(split, &mas_detach);
if (error)
goto munmap_sidetree_failed;
@ -2401,7 +2396,7 @@ do_mas_align_munmap(struct ma_state *mas, struct vm_area_struct *vma,
}
if (!next)
next = mas_next(mas, ULONG_MAX);
next = vma_next(vmi);
if (unlikely(uf)) {
/*
@ -2426,10 +2421,10 @@ do_mas_align_munmap(struct ma_state *mas, struct vm_area_struct *vma,
struct vm_area_struct *vma_mas, *vma_test;
int test_count = 0;
mas_set_range(mas, start, end - 1);
vma_iter_set(vmi, start);
rcu_read_lock();
vma_test = mas_find(&test, end - 1);
mas_for_each(mas, vma_mas, end - 1) {
for_each_vma_range(*vmi, vma_mas, end) {
BUG_ON(vma_mas != vma_test);
test_count++;
vma_test = mas_next(&test, end - 1);
@ -2439,8 +2434,8 @@ do_mas_align_munmap(struct ma_state *mas, struct vm_area_struct *vma,
}
#endif
/* Point of no return */
mas_set_range(mas, start, end - 1);
if (mas_store_gfp(mas, NULL, GFP_KERNEL))
vma_iter_set(vmi, start);
if (vma_iter_clear_gfp(vmi, start, end, GFP_KERNEL))
return -ENOMEM;
mm->map_count -= count;
@ -2478,8 +2473,8 @@ do_mas_align_munmap(struct ma_state *mas, struct vm_area_struct *vma,
}
/*
* do_mas_munmap() - munmap a given range.
* @mas: The maple state
* do_vmi_munmap() - munmap a given range.
* @vmi: The vma iterator
* @mm: The mm_struct
* @start: The start address to munmap
* @len: The length of the range to munmap
@ -2493,7 +2488,7 @@ do_mas_align_munmap(struct ma_state *mas, struct vm_area_struct *vma,
*
* Returns: -EINVAL on failure, 1 on success and unlock, 0 otherwise.
*/
int do_mas_munmap(struct ma_state *mas, struct mm_struct *mm,
int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm,
unsigned long start, size_t len, struct list_head *uf,
bool downgrade)
{
@ -2511,11 +2506,11 @@ int do_mas_munmap(struct ma_state *mas, struct mm_struct *mm,
arch_unmap(mm, start, end);
/* Find the first overlapping VMA */
vma = mas_find(mas, end - 1);
vma = vma_find(vmi, end);
if (!vma)
return 0;
return do_mas_align_munmap(mas, vma, mm, start, end, uf, downgrade);
return do_vmi_align_munmap(vmi, vma, mm, start, end, uf, downgrade);
}
/* do_munmap() - Wrapper function for non-maple tree aware do_munmap() calls.
@ -2527,9 +2522,9 @@ int do_mas_munmap(struct ma_state *mas, struct mm_struct *mm,
int do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
struct list_head *uf)
{
MA_STATE(mas, &mm->mm_mt, start, start);
VMA_ITERATOR(vmi, mm, start);
return do_mas_munmap(&mas, mm, start, len, uf, false);
return do_vmi_munmap(&vmi, mm, start, len, uf, false);
}
unsigned long mmap_region(struct file *file, unsigned long addr,
@ -2545,7 +2540,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
unsigned long merge_start = addr, merge_end = end;
pgoff_t vm_pgoff;
int error;
MA_STATE(mas, &mm->mm_mt, addr, end - 1);
VMA_ITERATOR(vmi, mm, addr);
/* Check against address space limit. */
if (!may_expand_vm(mm, vm_flags, len >> PAGE_SHIFT)) {
@ -2563,7 +2558,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
}
/* Unmap any existing mapping in the area */
if (do_mas_munmap(&mas, mm, addr, len, uf, false))
if (do_vmi_munmap(&vmi, mm, addr, len, uf, false))
return -ENOMEM;
/*
@ -2576,8 +2571,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
vm_flags |= VM_ACCOUNT;
}
next = mas_next(&mas, ULONG_MAX);
prev = mas_prev(&mas, 0);
next = vma_next(&vmi);
prev = vma_prev(&vmi);
if (vm_flags & VM_SPECIAL)
goto cannot_expand;
@ -2605,13 +2600,11 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
/* Actually expand, if possible */
if (vma &&
!vma_expand(&mas, vma, merge_start, merge_end, vm_pgoff, next)) {
!vma_expand(&vmi.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
@ -2650,7 +2643,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
error = -EINVAL;
goto close_and_free_vma;
}
mas_reset(&mas);
vma_iter_set(&vmi, addr);
/*
* If vm_flags changed after call_mmap(), we should try merge
@ -2706,7 +2699,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
goto free_vma;
}
if (mas_preallocate(&mas, GFP_KERNEL)) {
if (vma_iter_prealloc(&vmi)) {
error = -ENOMEM;
if (file)
goto close_and_free_vma;
@ -2719,7 +2712,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
if (vma->vm_file)
i_mmap_lock_write(vma->vm_file->f_mapping);
vma_mas_store(vma, &mas);
vma_iter_store(&vmi, vma);
mm->map_count++;
if (vma->vm_file) {
if (vma->vm_flags & VM_SHARED)
@ -2780,7 +2773,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
vma->vm_file = NULL;
/* Undo any partial mapping done by a device driver. */
unmap_region(mm, mas.tree, vma, prev, next, vma->vm_start, vma->vm_end);
unmap_region(mm, &mm->mm_mt, vma, prev, next, vma->vm_start, vma->vm_end);
if (file && (vm_flags & VM_SHARED))
mapping_unmap_writable(file->f_mapping);
free_vma:
@ -2797,12 +2790,12 @@ static int __vm_munmap(unsigned long start, size_t len, bool downgrade)
int ret;
struct mm_struct *mm = current->mm;
LIST_HEAD(uf);
MA_STATE(mas, &mm->mm_mt, start, start);
VMA_ITERATOR(vmi, mm, start);
if (mmap_write_lock_killable(mm))
return -EINTR;
ret = do_mas_munmap(&mas, mm, start, len, &uf, downgrade);
ret = do_vmi_munmap(&vmi, mm, start, len, &uf, downgrade);
/*
* Returning 1 indicates mmap_lock is downgraded.
* But 1 is not legal return value of vm_munmap() and munmap(), reset
@ -2934,7 +2927,7 @@ static int do_brk_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
int ret;
arch_unmap(mm, newbrk, oldbrk);
ret = do_mas_align_munmap(&vmi->mas, vma, mm, newbrk, oldbrk, uf, true);
ret = do_vmi_align_munmap(vmi, vma, mm, newbrk, oldbrk, uf, true);
validate_mm_mt(mm);
return ret;
}
@ -3057,7 +3050,7 @@ int vm_brk_flags(unsigned long addr, unsigned long request, unsigned long flags)
if (ret)
goto limits_failed;
ret = do_mas_munmap(&vmi.mas, mm, addr, len, &uf, 0);
ret = do_vmi_munmap(&vmi, mm, addr, len, &uf, 0);
if (ret)
goto munmap_failed;

6
mm/mremap.c
View file

@ -978,14 +978,14 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
/*
* Always allow a shrinking remap: that just unmaps
* the unnecessary pages..
* do_mas_munmap does all the needed commit accounting, and
* do_vmi_munmap does all the needed commit accounting, and
* downgrades mmap_lock to read if so directed.
*/
if (old_len >= new_len) {
int retval;
MA_STATE(mas, &mm->mm_mt, addr + new_len, addr + new_len);
VMA_ITERATOR(vmi, mm, addr + new_len);
retval = do_mas_munmap(&mas, mm, addr + new_len,
retval = do_vmi_munmap(&vmi, mm, addr + new_len,
old_len - new_len, &uf_unmap, true);
/* Returning 1 indicates mmap_lock is downgraded to read. */
if (retval == 1) {