mm/vma: support vma == NULL in init_vma_munmap()

Adding support for a NULL vma means the init_vma_munmap() can be
initialized for a less error-prone process when calling
vms_complete_munmap_vmas() later on.

Link: https://lkml.kernel.org/r/20240830040101.822209-11-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Bert Karwatzki <spasswolf@web.de>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Liam R. Howlett 2024-08-30 00:00:50 -04:00 committed by Andrew Morton
parent 9014b230d8
commit 58e60f8284
2 changed files with 9 additions and 4 deletions

View File

@ -1393,11 +1393,11 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
/* 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);
init_vma_munmap(&vms, &vmi, vma, addr, end, uf, /* unlock = */ false);
/* Prepare to unmap any existing mapping in the area */
error = vms_gather_munmap_vmas(&vms, &mas_detach);
if (error)

View File

@ -95,9 +95,14 @@ static inline void init_vma_munmap(struct vma_munmap_struct *vms,
{
vms->vmi = vmi;
vms->vma = vma;
vms->mm = vma->vm_mm;
vms->start = start;
vms->end = end;
if (vma) {
vms->mm = vma->vm_mm;
vms->start = start;
vms->end = end;
} else {
vms->mm = NULL;
vms->start = vms->end = 0;
}
vms->unlock = unlock;
vms->uf = uf;
vms->vma_count = 0;