mirrors
/
linux-stable
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
1
0
Fork 0
Code Issues Releases Wiki Activity

mm/mmap: introduce init_vma_prep() and init_multi_vma_prep() 

Add init_vma_prep() and init_multi_vma_prep() to set up the struct
vma_prepare.  This is to abstract the locking when adjusting the VMAs.

Also change __vma_adjust() variable remove_next int in favour of a pointer
to the VMA to remove.  Rename next_next to remove2 since this better
reflects its use.

Link: https://lkml.kernel.org/r/20230120162650.984577-43-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 11:26:43 -05:00 committed by Andrew Morton
parent 9303d3e1c3
commit 68cefec539
1 changed files with 61 additions and 47 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

108
mm/mmap.c
View File

@ -457,6 +457,45 @@ static int vma_link(struct mm_struct *mm, struct vm_area_struct *vma)
return 0;
}
/*
* init_multi_vma_prep() - Initializer for struct vma_prepare
* @vp: The vma_prepare struct
* @vma: The vma that will be altered once locked
* @next: The next vma if it is to be adjusted
* @remove: The first vma to be removed
* @remove2: The second vma to be removed
*/
static inline void init_multi_vma_prep(struct vma_prepare *vp,
struct vm_area_struct *vma, struct vm_area_struct *next,
struct vm_area_struct *remove, struct vm_area_struct *remove2)
{
memset(vp, 0, sizeof(struct vma_prepare));
vp->vma = vma;
vp->anon_vma = vma->anon_vma;
vp->remove = remove;
vp->remove2 = remove2;
vp->adj_next = next;
if (!vp->anon_vma && next)
vp->anon_vma = next->anon_vma;
vp->file = vma->vm_file;
if (vp->file)
vp->mapping = vma->vm_file->f_mapping;
}
/*
* init_vma_prep() - Initializer wrapper for vma_prepare struct
* @vp: The vma_prepare struct
* @vma: The vma that will be altered once locked
*/
static inline void init_vma_prep(struct vma_prepare *vp,
struct vm_area_struct *vma)
{
init_multi_vma_prep(vp, vma, NULL, NULL, NULL);
}
/*
* vma_prepare() - Helper function for handling locking VMAs prior to altering
* @vp: The initialized vma_prepare struct
@ -566,7 +605,7 @@ again:
/*
* In mprotect's case 6 (see comments on vma_merge),
* we must remove next_next too.
* we must remove the one after next as well.
*/
if (vp->remove2) {
vp->remove = vp->remove2;
@ -599,17 +638,14 @@ inline int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
unsigned long start, unsigned long end, pgoff_t pgoff,
struct vm_area_struct *next)
{
bool remove_next = false;
struct vma_prepare vp;
memset(&vp, 0, sizeof(vp));
vp.vma = vma;
vp.anon_vma = vma->anon_vma;
if (next && (vma != next) && (end == next->vm_end)) {
vp.remove = next;
remove_next = true;
if (next->anon_vma && !vma->anon_vma) {
int error;
vp.anon_vma = next->anon_vma;
vma->anon_vma = next->anon_vma;
error = anon_vma_clone(vma, next);
if (error)
@ -617,6 +653,7 @@ inline int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
}
}
init_multi_vma_prep(&vp, vma, NULL, remove_next ? next : NULL, NULL);
/* Not merging but overwriting any part of next is not handled. */
VM_WARN_ON(next && !vp.remove &&
next != vma && end > next->vm_start);
@ -627,11 +664,6 @@ inline int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
goto nomem;
vma_adjust_trans_huge(vma, start, end, 0);
vp.file = vma->vm_file;
if (vp.file)
vp.mapping = vp.file->f_mapping;
/* VMA iterator points to previous, so set to start if necessary */
if (vma_iter_addr(vmi) != start)
vma_iter_set(vmi, start);
@ -662,14 +694,13 @@ int __vma_adjust(struct vma_iterator *vmi, struct vm_area_struct *vma,
struct vm_area_struct *insert, struct vm_area_struct *expand)
{
struct mm_struct *mm = vma->vm_mm;
struct vm_area_struct *next_next = NULL; /* uninit var warning */
struct vm_area_struct *remove2 = NULL;
struct vm_area_struct *remove = NULL;
struct vm_area_struct *next = find_vma(mm, vma->vm_end);
struct vm_area_struct *orig_vma = vma;
struct anon_vma *anon_vma = NULL;
struct file *file = vma->vm_file;
bool vma_changed = false;
long adjust_next = 0;
int remove_next = 0;
struct vm_area_struct *exporter = NULL, *importer = NULL;
struct vma_prepare vma_prep;
@ -688,25 +719,24 @@ int __vma_adjust(struct vma_iterator *vmi, struct vm_area_struct *vma,
*/
VM_WARN_ON(end != next->vm_end);
/*
* remove_next == 3 means we're
* removing "vma" and that to do so we
* we're removing "vma" and that to do so we
* swapped "vma" and "next".
*/
remove_next = 3;
VM_WARN_ON(file != next->vm_file);
swap(vma, next);
remove = next;
} else {
VM_WARN_ON(expand != vma);
/*
* case 1, 6, 7, remove_next == 2 is case 6,
* remove_next == 1 is case 1 or 7.
* case 1, 6, 7, remove next.
* case 6 also removes the one beyond next
*/
remove_next = 1 + (end > next->vm_end);
if (remove_next == 2)
next_next = find_vma(mm, next->vm_end);
remove = next;
if (end > next->vm_end)
remove2 = find_vma(mm, next->vm_end);
VM_WARN_ON(remove_next == 2 &&
end != next_next->vm_end);
VM_WARN_ON(remove2 != NULL &&
end != remove2->vm_end);
}
exporter = next;
@ -716,8 +746,8 @@ int __vma_adjust(struct vma_iterator *vmi, struct vm_area_struct *vma,
* If next doesn't have anon_vma, import from vma after
* next, if the vma overlaps with it.
*/
if (remove_next == 2 && !next->anon_vma)
exporter = next_next;
if (remove2 != NULL && !next->anon_vma)
exporter = remove2;
} else if (end > next->vm_start) {
/*
@ -758,30 +788,14 @@ int __vma_adjust(struct vma_iterator *vmi, struct vm_area_struct *vma,
if (vma_iter_prealloc(vmi))
return -ENOMEM;
anon_vma = vma->anon_vma;
if (!anon_vma && adjust_next)
anon_vma = next->anon_vma;
if (anon_vma)
VM_WARN_ON(adjust_next && next->anon_vma &&
anon_vma != next->anon_vma);
vma_adjust_trans_huge(orig_vma, start, end, adjust_next);
memset(&vma_prep, 0, sizeof(vma_prep));
vma_prep.vma = vma;
vma_prep.anon_vma = anon_vma;
vma_prep.file = file;
if (adjust_next)
vma_prep.adj_next = next;
if (file)
vma_prep.mapping = file->f_mapping;
vma_prep.insert = insert;
if (remove_next) {
vma_prep.remove = next;
vma_prep.remove2 = next_next;
}
init_multi_vma_prep(&vma_prep, vma, adjust_next ? next : NULL, remove,
remove2);
VM_WARN_ON(vma_prep.anon_vma && adjust_next && next->anon_vma &&
vma_prep.anon_vma != next->anon_vma);
vma_prep.insert = insert;
vma_prepare(&vma_prep);
if (start != vma->vm_start) {