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mm/mremap: convert mremap code to use vma_flags_t

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Replace use of the legacy vm_flags_t flags with vma_flags_t values
throughout the mremap logic.

Note that, in replacing vm_flags_clear() (which takes the VMA write lock)
with vma_clear_flags() and vma_clear_flags_mask() (which do not)
respectively in unmap_source_vma() and dontunmap_complete(), we do not add
a VMA write lock to account for htis.

This is because, in both cases, move_vma() is their calling function and
this has already acquired the VMA write lock on vrm->vma whose VMA flags
are being cleared.

In the case of vma_set_flags() in unmap_source_vma() we do need to do this
- as prev and next were not necessarily write locked at this point.

Additionally update comments to reflect the changes to be consistent.

No functional change intended.

Link: https://lore.kernel.org/20260711-b4-vma-flags-mm-v2-13-0fa2357d5431@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nico Pache <npache@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Lorenzo Stoakes
2026-07-11 19:45:10 +01:00
committed by Andrew Morton
parent 31b50515a7
commit f4a31afd96
1 changed files with 20 additions and 18 deletions
Download Patch File Download Diff File Expand all files Collapse all files

38
mm/mremap.c
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@@ -68,7 +68,7 @@ struct vma_remap_struct {
bool populate_expand; /* mlock()'d expanded, must populate. */
enum mremap_type remap_type; /* expand, shrink, etc. */
bool mmap_locked; /* Is mm currently write-locked? */
unsigned long charged; /* If VM_ACCOUNT, # pages to account. */
unsigned long charged; /* If VMA_ACCOUNT_BIT, # pgs to account */
bool vmi_needs_invalidate; /* Is the VMA iterator invalidated? */
};
@@ -963,7 +963,7 @@ static unsigned long vrm_set_new_addr(struct vma_remap_struct *vrm)
if (vrm->flags & MREMAP_FIXED)
map_flags |= MAP_FIXED;
if (vma->vm_flags & VM_MAYSHARE)
if (vma_test(vma, VMA_MAYSHARE_BIT))
map_flags |= MAP_SHARED;
res = get_unmapped_area(vma->vm_file, new_addr, vrm->new_len, pgoff,
@@ -985,7 +985,7 @@ static bool vrm_calc_charge(struct vma_remap_struct *vrm)
{
unsigned long charged;
if (!(vrm->vma->vm_flags & VM_ACCOUNT))
if (!vma_test(vrm->vma, VMA_ACCOUNT_BIT))
return true;
/*
@@ -1012,7 +1012,7 @@ static bool vrm_calc_charge(struct vma_remap_struct *vrm)
*/
static void vrm_uncharge(struct vma_remap_struct *vrm)
{
if (!(vrm->vma->vm_flags & VM_ACCOUNT))
if (!vma_test(vrm->vma, VMA_ACCOUNT_BIT))
return;
vm_unacct_memory(vrm->charged);
@@ -1032,7 +1032,7 @@ static void vrm_stat_account(struct vma_remap_struct *vrm,
struct vm_area_struct *vma = vrm->vma;
vm_stat_account(mm, vma->vm_flags, pages);
if (vma->vm_flags & VM_LOCKED)
if (vma_test(vma, VMA_LOCKED_BIT))
mm->locked_vm += pages;
}
@@ -1176,7 +1176,7 @@ static void unmap_source_vma(struct vma_remap_struct *vrm)
* arose, in which case we _do_ wish to unmap the _new_ VMA, which means
* we actually _do_ want it be unaccounted.
*/
bool accountable_move = (vma->vm_flags & VM_ACCOUNT) &&
bool accountable_move = vma_test(vma, VMA_ACCOUNT_BIT) &&
!(vrm->flags & MREMAP_DONTUNMAP);
/*
@@ -1195,7 +1195,7 @@ static void unmap_source_vma(struct vma_remap_struct *vrm)
* portions of the original VMA that remain.
*/
if (accountable_move) {
vm_flags_clear(vma, VM_ACCOUNT);
vma_clear_flags(vma, VMA_ACCOUNT_BIT);
/* We are about to split vma, so store the start/end. */
vm_start = vma->vm_start;
vm_end = vma->vm_end;
@@ -1220,8 +1220,8 @@ static void unmap_source_vma(struct vma_remap_struct *vrm)
* | |
* |-------------|
*
* Having cleared VM_ACCOUNT from the whole VMA, after we unmap above
* we'll end up with:
* Having cleared VMA_ACCOUNT_BIT from the whole VMA, after we unmap
* above we'll end up with:
*
* addr end
* | |
@@ -1241,13 +1241,15 @@ static void unmap_source_vma(struct vma_remap_struct *vrm)
if (vm_start < addr) {
struct vm_area_struct *prev = vma_prev(&vmi);
vm_flags_set(prev, VM_ACCOUNT); /* Acquires VMA lock. */
vma_start_write(prev);
vma_set_flags(prev, VMA_ACCOUNT_BIT);
}
if (vm_end > end) {
struct vm_area_struct *next = vma_next(&vmi);
vm_flags_set(next, VM_ACCOUNT); /* Acquires VMA lock. */
vma_start_write(next);
vma_set_flags(next, VMA_ACCOUNT_BIT);
}
}
}
@@ -1330,8 +1332,8 @@ static void dontunmap_complete(struct vma_remap_struct *vrm,
unsigned long old_start = vrm->vma->vm_start;
unsigned long old_end = vrm->vma->vm_end;
/* We always clear VM_LOCKED[ONFAULT] on the old VMA. */
vm_flags_clear(vrm->vma, VM_LOCKED_MASK);
/* We always clear VMA_LOCKED[ONFAULT]_BIT on the old VMA. */
vma_clear_flags_mask(vrm->vma, VMA_LOCKED_MASK);
/*
* anon_vma links of the old vma is no longer needed after its page
@@ -1767,14 +1769,14 @@ static int check_prep_vma(struct vma_remap_struct *vrm)
* based on the original. There are no known use cases for this
* behavior. As a result, fail such attempts.
*/
if (!old_len && !(vma->vm_flags & (VM_SHARED | VM_MAYSHARE))) {
if (!old_len && !vma_test_any(vma, VMA_SHARED_BIT, VMA_MAYSHARE_BIT)) {
pr_warn_once("%s (%d): attempted to duplicate a private mapping with mremap. This is not supported.\n",
current->comm, current->pid);
return -EINVAL;
}
if ((vrm->flags & MREMAP_DONTUNMAP) &&
(vma->vm_flags & (VM_DONTEXPAND | VM_PFNMAP)))
vma_test_any(vma, VMA_DONTEXPAND_BIT, VMA_PFNMAP_BIT))
return -EINVAL;
/*
@@ -1804,7 +1806,7 @@ static int check_prep_vma(struct vma_remap_struct *vrm)
return 0;
/* We are expanding and the VMA is mlock()'d so we need to populate. */
if (vma->vm_flags & VM_LOCKED)
if (vma_test(vma, VMA_LOCKED_BIT))
vrm->populate_expand = true;
/* Need to be careful about a growing mapping */
@@ -1812,10 +1814,10 @@ static int check_prep_vma(struct vma_remap_struct *vrm)
if (pgoff + (new_len >> PAGE_SHIFT) < pgoff)
return -EINVAL;
if (vma->vm_flags & (VM_DONTEXPAND | VM_PFNMAP))
if (vma_test_any(vma, VMA_DONTEXPAND_BIT, VMA_PFNMAP_BIT))
return -EFAULT;
if (!mlock_future_ok(mm, vma->vm_flags & VM_LOCKED, vrm->delta))
if (!mlock_future_ok(mm, vma_test(vma, VMA_LOCKED_BIT), vrm->delta))
return -EAGAIN;
if (!may_expand_vm(mm, &vma->flags, vrm->delta >> PAGE_SHIFT))