[PATCH v2 13/13] mm/mremap: convert mremap code to use vma_flags_t
From: Lorenzo Stoakes <ljs@kernel.org>
Date: 2026-07-11 18:50:14
Also in:
dri-devel, intel-gfx, intel-xe, linux-arm-msm, linux-fsdevel, linux-mips, linux-mm, linux-samsung-soc, linux-sound, linux-tegra, linuxppc-dev, lkml, nouveau, virtualization, xen-devel
Subsystem:
memory management, memory mapping, the rest · Maintainers:
Andrew Morton, Liam R. Howlett, Lorenzo Stoakes, Linus Torvalds
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. Reviewed-by: Zi Yan <ziy@nvidia.com> Signed-off-by: Lorenzo Stoakes <ljs@kernel.org> --- mm/mremap.c | 38 ++++++++++++++++++++------------------ 1 file changed, 20 insertions(+), 18 deletions(-)
diff --git a/mm/mremap.c b/mm/mremap.c
index 384ef4cc2195..b64aa1f6e07e 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c@@ -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))
--
2.55.0