The adj_start calculation has been a constant source of confusion in the
VMA merge code.
There are two cases to consider, one where we adjust the start of the
vmg->middle VMA (i.e. the __VMG_FLAG_ADJUST_MIDDLE_START merge flag is
set), in which case adj_start is calculated as:
(1) adj_start = vmg->end - vmg->middle->vm_start
And the case where we adjust the start of the vmg->next VMA (i.e.t he
__VMG_FLAG_ADJUST_NEXT_START merge flag is set), in which case adj_start is
calculated as:
(2) adj_start = -(vmg->middle->vm_end - vmg->end)
We apply (1) thusly:
vmg->middle->vm_start =
vmg->middle->vm_start + vmg->end - vmg->middle->vm_start
Which simplifies to:
vmg->middle->vm_start = vmg->end
Similarly, we apply (2) as:
vmg->next->vm_start =
vmg->next->vm_start + -(vmg->middle->vm_end - vmg->end)
Noting that for these VMAs to be mergeable vmg->middle->vm_end ==
vmg->next->vm_start and so this simplifies to:
vmg->next->vm_start =
vmg->next->vm_start + -(vmg->next->vm_start - vmg->end)
Which simplifies to:
vmg->next->vm_start = vmg->end
Therefore in each case, we simply need to adjust the start of the VMA to
vmg->end (!) and can do away with this adj_start calculation. The only
caveat is that we must ensure we update the vm_pgoff field correctly.
We therefore abstract this entire calculation to a new function
vmg_adjust_set_range() which performs this calculation and sets the
adjusted VMA's new range using the general vma_set_range() function.
We also must update vma_adjust_trans_huge() which expects the
now-abstracted adj_start parameter. It turns out this is wholly
unnecessary.
In vma_adjust_trans_huge() the relevant code is:
if (adjust_next > 0) {
struct vm_area_struct *next = find_vma(vma->vm_mm, vma->vm_end);
unsigned long nstart = next->vm_start;
nstart += adjust_next;
split_huge_pmd_if_needed(next, nstart);
}
The only case where this is relevant is when __VMG_FLAG_ADJUST_MIDDLE_START
is specified (in which case adj_next would have been positive), i.e. the
one in which the vma specified is vmg->prev and this the sought 'next' VMA
would be vmg->middle.
We can therefore eliminate the find_vma() invocation altogether and simply
provide the vmg->middle VMA in this instance, or NULL otherwise.
Again we have an adj_next offset calculation:
next->vm_start + vmg->end - vmg->middle->vm_start
Where next == vmg->middle this simplifies to vmg->end as previously
demonstrated.
Therefore nstart is equal to vmg->end, which is already passed to
vma_adjust_trans_huge() via the 'end' parameter and so this code (rather
delightfully) simplifies to:
if (next)
split_huge_pmd_if_needed(next, end);
With these changes in place, it becomes silly for commit_merge() to return
vmg->target, as it is always the same and threaded through vmg, so we
finally change commit_merge() to return an error value once again.
This patch has no change in functional behaviour.
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
---
include/linux/huge_mm.h | 2 +-
mm/huge_memory.c | 19 ++----
mm/vma.c | 102 +++++++++++++++----------------
tools/testing/vma/vma_internal.h | 4 +-
4 files changed, 58 insertions(+), 69 deletions(-)
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 93e509b6c00e..43f76b54b522 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -404,7 +404,7 @@ int madvise_collapse(struct vm_area_struct *vma,
struct vm_area_struct **prev,
unsigned long start, unsigned long end);
void vma_adjust_trans_huge(struct vm_area_struct *vma, unsigned long start,
- unsigned long end, long adjust_next);
+ unsigned long end, struct vm_area_struct *next);
spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma);
spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma);
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 3d3ebdc002d5..c44599f9ad09 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3017,9 +3017,9 @@ static inline void split_huge_pmd_if_needed(struct vm_area_struct *vma, unsigned
}
void vma_adjust_trans_huge(struct vm_area_struct *vma,
- unsigned long start,
- unsigned long end,
- long adjust_next)
+ unsigned long start,
+ unsigned long end,
+ struct vm_area_struct *next)
{
/* Check if we need to split start first. */
split_huge_pmd_if_needed(vma, start);
@@ -3027,16 +3027,9 @@ void vma_adjust_trans_huge(struct vm_area_struct *vma,
/* Check if we need to split end next. */
split_huge_pmd_if_needed(vma, end);
- /*
- * If we're also updating the next vma vm_start,
- * check if we need to split it.
- */
- if (adjust_next > 0) {
- struct vm_area_struct *next = find_vma(vma->vm_mm, vma->vm_end);
- unsigned long nstart = next->vm_start;
- nstart += adjust_next;
- split_huge_pmd_if_needed(next, nstart);
- }
+ /* If we're incrementing next->vm_start, we might need to split it. */
+ if (next)
+ split_huge_pmd_if_needed(next, end);
}
static void unmap_folio(struct folio *folio)
diff --git a/mm/vma.c b/mm/vma.c
index cfcadca7b116..48a7acc83a82 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -515,7 +515,7 @@ __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
init_vma_prep(&vp, vma);
vp.insert = new;
vma_prepare(&vp);
- vma_adjust_trans_huge(vma, vma->vm_start, addr, 0);
+ vma_adjust_trans_huge(vma, vma->vm_start, addr, NULL);
if (new_below) {
vma->vm_start = addr;
@@ -646,47 +646,46 @@ void validate_mm(struct mm_struct *mm)
#endif /* CONFIG_DEBUG_VM_MAPLE_TREE */
/*
- * Actually perform the VMA merge operation.
- *
- * On success, returns the merged VMA. Otherwise returns NULL.
+ * Based on the vmg flag indicating whether we need to adjust the vm_start field
+ * for the middle or next VMA, we calculate what the range of the newly adjusted
+ * VMA ought to be, and set the VMA's range accordingly.
*/
-static struct vm_area_struct *commit_merge(struct vma_merge_struct *vmg)
+static void vmg_adjust_set_range(struct vma_merge_struct *vmg)
{
- struct vm_area_struct *vma;
- struct vma_prepare vp;
- struct vm_area_struct *adjust;
- long adj_start;
unsigned long flags = vmg->merge_flags;
+ struct vm_area_struct *adjust;
+ pgoff_t pgoff;
- /*
- * If modifying an existing VMA and we don't remove vmg->middle, then we
- * shrink the adjacent VMA.
- */
if (flags & __VMG_FLAG_ADJUST_MIDDLE_START) {
- vma = vmg->target;
adjust = vmg->middle;
- /* The POSITIVE value by which we offset vmg->middle->vm_start. */
- adj_start = vmg->end - vmg->middle->vm_start;
-
- /* Note: vma iterator must be pointing to 'start'. */
- vma_iter_config(vmg->vmi, vmg->start, vmg->end);
+ pgoff = adjust->vm_pgoff + PHYS_PFN(vmg->end - adjust->vm_start);
} else if (flags & __VMG_FLAG_ADJUST_NEXT_START) {
- /*
- * In this case alone, the VMA we manipulate is vmg->middle, but
- * we ultimately return vmg->next.
- */
- vma = vmg->middle;
adjust = vmg->next;
- /* The NEGATIVE value by which we offset vmg->next->vm_start. */
- adj_start = -(vmg->middle->vm_end - vmg->end);
+ pgoff = adjust->vm_pgoff - PHYS_PFN(adjust->vm_start - vmg->end);
+ } else {
+ return;
+ }
+
+ vma_set_range(adjust, vmg->end, adjust->vm_end, pgoff);
+}
+
+/*
+ * Actually perform the VMA merge operation.
+ *
+ * On success, returns the merged VMA. Otherwise returns NULL.
+ */
+static int commit_merge(struct vma_merge_struct *vmg)
+{
+ struct vm_area_struct *vma;
+ struct vma_prepare vp;
+ bool adj_middle = vmg->merge_flags & __VMG_FLAG_ADJUST_MIDDLE_START;
- vma_iter_config(vmg->vmi, vmg->next->vm_start + adj_start,
- vmg->next->vm_end);
+ if (vmg->merge_flags & __VMG_FLAG_ADJUST_NEXT_START) {
+ /* In this case we manipulate middle and return next. */
+ vma = vmg->middle;
+ vma_iter_config(vmg->vmi, vmg->end, vmg->next->vm_end);
} else {
vma = vmg->target;
- adjust = NULL;
- adj_start = 0;
-
/* Note: vma iterator must be pointing to 'start'. */
vma_iter_config(vmg->vmi, vmg->start, vmg->end);
}
@@ -694,22 +693,22 @@ static struct vm_area_struct *commit_merge(struct vma_merge_struct *vmg)
init_multi_vma_prep(&vp, vma, vmg);
if (vma_iter_prealloc(vmg->vmi, vma))
- return NULL;
+ return -ENOMEM;
vma_prepare(&vp);
- vma_adjust_trans_huge(vma, vmg->start, vmg->end, adj_start);
+ /*
+ * THP pages may need to do additional splits if we increase
+ * middle->vm_start.
+ */
+ vma_adjust_trans_huge(vma, vmg->start, vmg->end,
+ adj_middle ? vmg->middle : NULL);
vma_set_range(vma, vmg->start, vmg->end, vmg->pgoff);
-
- if (adj_start) {
- adjust->vm_start += adj_start;
- adjust->vm_pgoff += PHYS_PFN(adj_start);
- }
-
+ vmg_adjust_set_range(vmg);
vma_iter_store(vmg->vmi, vmg->target);
vma_complete(&vp, vmg->vmi, vma->vm_mm);
- return vmg->target;
+ return 0;
}
/* We can only remove VMAs when merging if they do not have a close hook. */
@@ -752,7 +751,7 @@ static __must_check struct vm_area_struct *vma_merge_existing_range(
{
struct vm_area_struct *middle = vmg->middle;
struct vm_area_struct *prev = vmg->prev;
- struct vm_area_struct *next, *res;
+ struct vm_area_struct *next;
struct vm_area_struct *anon_dup = NULL;
unsigned long start = vmg->start;
unsigned long end = vmg->end;
@@ -904,12 +903,7 @@ static __must_check struct vm_area_struct *vma_merge_existing_range(
vmg->end = next->vm_end;
vmg->pgoff = next->vm_pgoff - pglen;
} else {
- /*
- * We shrink middle and expand next.
- *
- * IMPORTANT: This is the ONLY case where the final
- * merged VMA is NOT vmg->target, but rather vmg->next.
- */
+ /* We shrink middle and expand next. */
vmg->merge_flags |= __VMG_FLAG_ADJUST_NEXT_START;
vmg->start = middle->vm_start;
vmg->end = start;
@@ -927,8 +921,10 @@ static __must_check struct vm_area_struct *vma_merge_existing_range(
if (merge_will_delete_next)
vmg->merge_flags |= __VMG_FLAG_REMOVE_NEXT;
- res = commit_merge(vmg);
- if (!res) {
+ err = commit_merge(vmg);
+ if (err) {
+ VM_WARN_ON(err != -ENOMEM);
+
if (anon_dup)
unlink_anon_vmas(anon_dup);
@@ -936,9 +932,9 @@ static __must_check struct vm_area_struct *vma_merge_existing_range(
return NULL;
}
- khugepaged_enter_vma(res, vmg->flags);
+ khugepaged_enter_vma(vmg->target, vmg->flags);
vmg->state = VMA_MERGE_SUCCESS;
- return res;
+ return vmg->target;
abort:
vma_iter_set(vmg->vmi, start);
@@ -1102,7 +1098,7 @@ int vma_expand(struct vma_merge_struct *vmg)
if (remove_next)
vmg->merge_flags |= __VMG_FLAG_REMOVE_NEXT;
- if (!commit_merge(vmg))
+ if (commit_merge(vmg))
goto nomem;
return 0;
@@ -1142,7 +1138,7 @@ int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma,
init_vma_prep(&vp, vma);
vma_prepare(&vp);
- vma_adjust_trans_huge(vma, start, end, 0);
+ vma_adjust_trans_huge(vma, start, end, NULL);
vma_iter_clear(vmi);
vma_set_range(vma, start, end, pgoff);
diff --git a/tools/testing/vma/vma_internal.h b/tools/testing/vma/vma_internal.h
index 1eae23039854..bb273927af0f 100644
--- a/tools/testing/vma/vma_internal.h
+++ b/tools/testing/vma/vma_internal.h
@@ -796,12 +796,12 @@ static inline void vma_start_write(struct vm_area_struct *vma)
static inline void vma_adjust_trans_huge(struct vm_area_struct *vma,
unsigned long start,
unsigned long end,
- long adjust_next)
+ struct vm_area_struct *next)
{
(void)vma;
(void)start;
(void)end;
- (void)adjust_next;
+ (void)next;
}
static inline void vma_iter_free(struct vma_iterator *vmi)
--
2.48.0On 1/27/25 16:50, Lorenzo Stoakes wrote:
> The adj_start calculation has been a constant source of confusion in the
> VMA merge code.
>
> There are two cases to consider, one where we adjust the start of the
> vmg->middle VMA (i.e. the __VMG_FLAG_ADJUST_MIDDLE_START merge flag is
> set), in which case adj_start is calculated as:
>
> (1) adj_start = vmg->end - vmg->middle->vm_start
>
> And the case where we adjust the start of the vmg->next VMA (i.e.t he
> __VMG_FLAG_ADJUST_NEXT_START merge flag is set), in which case adj_start is
> calculated as:
>
> (2) adj_start = -(vmg->middle->vm_end - vmg->end)
>
> We apply (1) thusly:
>
> vmg->middle->vm_start =
> vmg->middle->vm_start + vmg->end - vmg->middle->vm_start
>
> Which simplifies to:
>
> vmg->middle->vm_start = vmg->end
>
> Similarly, we apply (2) as:
>
> vmg->next->vm_start =
> vmg->next->vm_start + -(vmg->middle->vm_end - vmg->end)
>
> Noting that for these VMAs to be mergeable vmg->middle->vm_end ==
> vmg->next->vm_start and so this simplifies to:
>
> vmg->next->vm_start =
> vmg->next->vm_start + -(vmg->next->vm_start - vmg->end)
>
> Which simplifies to:
>
> vmg->next->vm_start = vmg->end
>
> Therefore in each case, we simply need to adjust the start of the VMA to
> vmg->end (!) and can do away with this adj_start calculation. The only
> caveat is that we must ensure we update the vm_pgoff field correctly.
>
> We therefore abstract this entire calculation to a new function
> vmg_adjust_set_range() which performs this calculation and sets the
> adjusted VMA's new range using the general vma_set_range() function.
>
> We also must update vma_adjust_trans_huge() which expects the
> now-abstracted adj_start parameter. It turns out this is wholly
> unnecessary.
>
> In vma_adjust_trans_huge() the relevant code is:
>
> if (adjust_next > 0) {
> struct vm_area_struct *next = find_vma(vma->vm_mm, vma->vm_end);
> unsigned long nstart = next->vm_start;
> nstart += adjust_next;
> split_huge_pmd_if_needed(next, nstart);
> }
>
> The only case where this is relevant is when __VMG_FLAG_ADJUST_MIDDLE_START
> is specified (in which case adj_next would have been positive), i.e. the
> one in which the vma specified is vmg->prev and this the sought 'next' VMA
> would be vmg->middle.
>
> We can therefore eliminate the find_vma() invocation altogether and simply
> provide the vmg->middle VMA in this instance, or NULL otherwise.
>
> Again we have an adj_next offset calculation:
>
> next->vm_start + vmg->end - vmg->middle->vm_start
>
> Where next == vmg->middle this simplifies to vmg->end as previously
> demonstrated.
>
> Therefore nstart is equal to vmg->end, which is already passed to
> vma_adjust_trans_huge() via the 'end' parameter and so this code (rather
> delightfully) simplifies to:
>
> if (next)
> split_huge_pmd_if_needed(next, end);
>
> With these changes in place, it becomes silly for commit_merge() to return
> vmg->target, as it is always the same and threaded through vmg, so we
> finally change commit_merge() to return an error value once again.
>
> This patch has no change in functional behaviour.
>
> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Yeah this makes the preparations worth it. Nice!
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
> +/*
> + * Actually perform the VMA merge operation.
> + *
> + * On success, returns the merged VMA. Otherwise returns NULL.
Needs updating?
> + */
> +static int commit_merge(struct vma_merge_struct *vmg)
> +{
> + struct vm_area_struct *vma;
> + struct vma_prepare vp;
> + bool adj_middle = vmg->merge_flags & __VMG_FLAG_ADJUST_MIDDLE_START;
>
> - vma_iter_config(vmg->vmi, vmg->next->vm_start + adj_start,
> - vmg->next->vm_end);
> + if (vmg->merge_flags & __VMG_FLAG_ADJUST_NEXT_START) {
> + /* In this case we manipulate middle and return next. */
Also we don't return next anymore? At least not here.
vma_merge_existing_range() does, but here it's rather "the target is next"?
> + vma = vmg->middle;
> + vma_iter_config(vmg->vmi, vmg->end, vmg->next->vm_end);
> } else {
On Wed, Jan 29, 2025 at 04:42:06PM +0100, Vlastimil Babka wrote:
> On 1/27/25 16:50, Lorenzo Stoakes wrote:
> > The adj_start calculation has been a constant source of confusion in the
> > VMA merge code.
> >
> > There are two cases to consider, one where we adjust the start of the
> > vmg->middle VMA (i.e. the __VMG_FLAG_ADJUST_MIDDLE_START merge flag is
> > set), in which case adj_start is calculated as:
> >
> > (1) adj_start = vmg->end - vmg->middle->vm_start
> >
> > And the case where we adjust the start of the vmg->next VMA (i.e.t he
> > __VMG_FLAG_ADJUST_NEXT_START merge flag is set), in which case adj_start is
> > calculated as:
> >
> > (2) adj_start = -(vmg->middle->vm_end - vmg->end)
> >
> > We apply (1) thusly:
> >
> > vmg->middle->vm_start =
> > vmg->middle->vm_start + vmg->end - vmg->middle->vm_start
> >
> > Which simplifies to:
> >
> > vmg->middle->vm_start = vmg->end
> >
> > Similarly, we apply (2) as:
> >
> > vmg->next->vm_start =
> > vmg->next->vm_start + -(vmg->middle->vm_end - vmg->end)
> >
> > Noting that for these VMAs to be mergeable vmg->middle->vm_end ==
> > vmg->next->vm_start and so this simplifies to:
> >
> > vmg->next->vm_start =
> > vmg->next->vm_start + -(vmg->next->vm_start - vmg->end)
> >
> > Which simplifies to:
> >
> > vmg->next->vm_start = vmg->end
> >
> > Therefore in each case, we simply need to adjust the start of the VMA to
> > vmg->end (!) and can do away with this adj_start calculation. The only
> > caveat is that we must ensure we update the vm_pgoff field correctly.
> >
> > We therefore abstract this entire calculation to a new function
> > vmg_adjust_set_range() which performs this calculation and sets the
> > adjusted VMA's new range using the general vma_set_range() function.
> >
> > We also must update vma_adjust_trans_huge() which expects the
> > now-abstracted adj_start parameter. It turns out this is wholly
> > unnecessary.
> >
> > In vma_adjust_trans_huge() the relevant code is:
> >
> > if (adjust_next > 0) {
> > struct vm_area_struct *next = find_vma(vma->vm_mm, vma->vm_end);
> > unsigned long nstart = next->vm_start;
> > nstart += adjust_next;
> > split_huge_pmd_if_needed(next, nstart);
> > }
> >
> > The only case where this is relevant is when __VMG_FLAG_ADJUST_MIDDLE_START
> > is specified (in which case adj_next would have been positive), i.e. the
> > one in which the vma specified is vmg->prev and this the sought 'next' VMA
> > would be vmg->middle.
> >
> > We can therefore eliminate the find_vma() invocation altogether and simply
> > provide the vmg->middle VMA in this instance, or NULL otherwise.
> >
> > Again we have an adj_next offset calculation:
> >
> > next->vm_start + vmg->end - vmg->middle->vm_start
> >
> > Where next == vmg->middle this simplifies to vmg->end as previously
> > demonstrated.
> >
> > Therefore nstart is equal to vmg->end, which is already passed to
> > vma_adjust_trans_huge() via the 'end' parameter and so this code (rather
> > delightfully) simplifies to:
> >
> > if (next)
> > split_huge_pmd_if_needed(next, end);
> >
> > With these changes in place, it becomes silly for commit_merge() to return
> > vmg->target, as it is always the same and threaded through vmg, so we
> > finally change commit_merge() to return an error value once again.
> >
> > This patch has no change in functional behaviour.
> >
> > Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
>
> Yeah this makes the preparations worth it. Nice!
>
> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Thanks!
>
> > +/*
> > + * Actually perform the VMA merge operation.
> > + *
> > + * On success, returns the merged VMA. Otherwise returns NULL.
>
> Needs updating?
Ah yeah you're right, will fix!
>
> > + */
> > +static int commit_merge(struct vma_merge_struct *vmg)
> > +{
> > + struct vm_area_struct *vma;
> > + struct vma_prepare vp;
> > + bool adj_middle = vmg->merge_flags & __VMG_FLAG_ADJUST_MIDDLE_START;
> >
> > - vma_iter_config(vmg->vmi, vmg->next->vm_start + adj_start,
> > - vmg->next->vm_end);
> > + if (vmg->merge_flags & __VMG_FLAG_ADJUST_NEXT_START) {
> > + /* In this case we manipulate middle and return next. */
>
> Also we don't return next anymore? At least not here.
> vma_merge_existing_range() does, but here it's rather "the target is next"?
Yeah we should reword as you say, will fix!
>
> > + vma = vmg->middle;
> > + vma_iter_config(vmg->vmi, vmg->end, vmg->next->vm_end);
> > } else {
Hi Lorenzo,
kernel test robot noticed the following build warnings:
[auto build test WARNING on akpm-mm/mm-everything]
url: https://github.com/intel-lab-lkp/linux/commits/Lorenzo-Stoakes/mm-simplify-vma-merge-structure-and-expand-comments/20250127-235322
base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link: https://lore.kernel.org/r/ef00aec42a892fe6ac9557b3a11f18f30a2e51b3.1737929364.git.lorenzo.stoakes%40oracle.com
patch subject: [PATCH 5/5] mm: completely abstract unnecessary adj_start calculation
config: x86_64-randconfig-122-20250128 (https://download.01.org/0day-ci/archive/20250128/202501281552.zDLVA5oq-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250128/202501281552.zDLVA5oq-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202501281552.zDLVA5oq-lkp@intel.com/
sparse warnings: (new ones prefixed by >>)
>> mm/vma.c:518:57: sparse: sparse: incorrect type in argument 4 (different base types) @@ expected long adjust_next @@ got void * @@
mm/vma.c:518:57: sparse: expected long adjust_next
mm/vma.c:518:57: sparse: got void *
>> mm/vma.c:704:42: sparse: sparse: incorrect type in argument 4 (different base types) @@ expected long adjust_next @@ got struct vm_area_struct * @@
mm/vma.c:704:42: sparse: expected long adjust_next
mm/vma.c:704:42: sparse: got struct vm_area_struct *
mm/vma.c:1141:48: sparse: sparse: incorrect type in argument 4 (different base types) @@ expected long adjust_next @@ got void * @@
mm/vma.c:1141:48: sparse: expected long adjust_next
mm/vma.c:1141:48: sparse: got void *
vim +518 mm/vma.c
459
460 /*
461 * __split_vma() bypasses sysctl_max_map_count checking. We use this where it
462 * has already been checked or doesn't make sense to fail.
463 * VMA Iterator will point to the original VMA.
464 */
465 static __must_check int
466 __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
467 unsigned long addr, int new_below)
468 {
469 struct vma_prepare vp;
470 struct vm_area_struct *new;
471 int err;
472
473 WARN_ON(vma->vm_start >= addr);
474 WARN_ON(vma->vm_end <= addr);
475
476 if (vma->vm_ops && vma->vm_ops->may_split) {
477 err = vma->vm_ops->may_split(vma, addr);
478 if (err)
479 return err;
480 }
481
482 new = vm_area_dup(vma);
483 if (!new)
484 return -ENOMEM;
485
486 if (new_below) {
487 new->vm_end = addr;
488 } else {
489 new->vm_start = addr;
490 new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
491 }
492
493 err = -ENOMEM;
494 vma_iter_config(vmi, new->vm_start, new->vm_end);
495 if (vma_iter_prealloc(vmi, new))
496 goto out_free_vma;
497
498 err = vma_dup_policy(vma, new);
499 if (err)
500 goto out_free_vmi;
501
502 err = anon_vma_clone(new, vma);
503 if (err)
504 goto out_free_mpol;
505
506 if (new->vm_file)
507 get_file(new->vm_file);
508
509 if (new->vm_ops && new->vm_ops->open)
510 new->vm_ops->open(new);
511
512 vma_start_write(vma);
513 vma_start_write(new);
514
515 init_vma_prep(&vp, vma);
516 vp.insert = new;
517 vma_prepare(&vp);
> 518 vma_adjust_trans_huge(vma, vma->vm_start, addr, NULL);
519
520 if (new_below) {
521 vma->vm_start = addr;
522 vma->vm_pgoff += (addr - new->vm_start) >> PAGE_SHIFT;
523 } else {
524 vma->vm_end = addr;
525 }
526
527 /* vma_complete stores the new vma */
528 vma_complete(&vp, vmi, vma->vm_mm);
529 validate_mm(vma->vm_mm);
530
531 /* Success. */
532 if (new_below)
533 vma_next(vmi);
534 else
535 vma_prev(vmi);
536
537 return 0;
538
539 out_free_mpol:
540 mpol_put(vma_policy(new));
541 out_free_vmi:
542 vma_iter_free(vmi);
543 out_free_vma:
544 vm_area_free(new);
545 return err;
546 }
547
548 /*
549 * Split a vma into two pieces at address 'addr', a new vma is allocated
550 * either for the first part or the tail.
551 */
552 static int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
553 unsigned long addr, int new_below)
554 {
555 if (vma->vm_mm->map_count >= sysctl_max_map_count)
556 return -ENOMEM;
557
558 return __split_vma(vmi, vma, addr, new_below);
559 }
560
561 /*
562 * dup_anon_vma() - Helper function to duplicate anon_vma
563 * @dst: The destination VMA
564 * @src: The source VMA
565 * @dup: Pointer to the destination VMA when successful.
566 *
567 * Returns: 0 on success.
568 */
569 static int dup_anon_vma(struct vm_area_struct *dst,
570 struct vm_area_struct *src, struct vm_area_struct **dup)
571 {
572 /*
573 * Easily overlooked: when mprotect shifts the boundary, make sure the
574 * expanding vma has anon_vma set if the shrinking vma had, to cover any
575 * anon pages imported.
576 */
577 if (src->anon_vma && !dst->anon_vma) {
578 int ret;
579
580 vma_assert_write_locked(dst);
581 dst->anon_vma = src->anon_vma;
582 ret = anon_vma_clone(dst, src);
583 if (ret)
584 return ret;
585
586 *dup = dst;
587 }
588
589 return 0;
590 }
591
592 #ifdef CONFIG_DEBUG_VM_MAPLE_TREE
593 void validate_mm(struct mm_struct *mm)
594 {
595 int bug = 0;
596 int i = 0;
597 struct vm_area_struct *vma;
598 VMA_ITERATOR(vmi, mm, 0);
599
600 mt_validate(&mm->mm_mt);
601 for_each_vma(vmi, vma) {
602 #ifdef CONFIG_DEBUG_VM_RB
603 struct anon_vma *anon_vma = vma->anon_vma;
604 struct anon_vma_chain *avc;
605 #endif
606 unsigned long vmi_start, vmi_end;
607 bool warn = 0;
608
609 vmi_start = vma_iter_addr(&vmi);
610 vmi_end = vma_iter_end(&vmi);
611 if (VM_WARN_ON_ONCE_MM(vma->vm_end != vmi_end, mm))
612 warn = 1;
613
614 if (VM_WARN_ON_ONCE_MM(vma->vm_start != vmi_start, mm))
615 warn = 1;
616
617 if (warn) {
618 pr_emerg("issue in %s\n", current->comm);
619 dump_stack();
620 dump_vma(vma);
621 pr_emerg("tree range: %px start %lx end %lx\n", vma,
622 vmi_start, vmi_end - 1);
623 vma_iter_dump_tree(&vmi);
624 }
625
626 #ifdef CONFIG_DEBUG_VM_RB
627 if (anon_vma) {
628 anon_vma_lock_read(anon_vma);
629 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
630 anon_vma_interval_tree_verify(avc);
631 anon_vma_unlock_read(anon_vma);
632 }
633 #endif
634 /* Check for a infinite loop */
635 if (++i > mm->map_count + 10) {
636 i = -1;
637 break;
638 }
639 }
640 if (i != mm->map_count) {
641 pr_emerg("map_count %d vma iterator %d\n", mm->map_count, i);
642 bug = 1;
643 }
644 VM_BUG_ON_MM(bug, mm);
645 }
646 #endif /* CONFIG_DEBUG_VM_MAPLE_TREE */
647
648 /*
649 * Based on the vmg flag indicating whether we need to adjust the vm_start field
650 * for the middle or next VMA, we calculate what the range of the newly adjusted
651 * VMA ought to be, and set the VMA's range accordingly.
652 */
653 static void vmg_adjust_set_range(struct vma_merge_struct *vmg)
654 {
655 unsigned long flags = vmg->merge_flags;
656 struct vm_area_struct *adjust;
657 pgoff_t pgoff;
658
659 if (flags & __VMG_FLAG_ADJUST_MIDDLE_START) {
660 adjust = vmg->middle;
661 pgoff = adjust->vm_pgoff + PHYS_PFN(vmg->end - adjust->vm_start);
662 } else if (flags & __VMG_FLAG_ADJUST_NEXT_START) {
663 adjust = vmg->next;
664 pgoff = adjust->vm_pgoff - PHYS_PFN(adjust->vm_start - vmg->end);
665 } else {
666 return;
667 }
668
669 vma_set_range(adjust, vmg->end, adjust->vm_end, pgoff);
670 }
671
672 /*
673 * Actually perform the VMA merge operation.
674 *
675 * On success, returns the merged VMA. Otherwise returns NULL.
676 */
677 static int commit_merge(struct vma_merge_struct *vmg)
678 {
679 struct vm_area_struct *vma;
680 struct vma_prepare vp;
681 bool adj_middle = vmg->merge_flags & __VMG_FLAG_ADJUST_MIDDLE_START;
682
683 if (vmg->merge_flags & __VMG_FLAG_ADJUST_NEXT_START) {
684 /* In this case we manipulate middle and return next. */
685 vma = vmg->middle;
686 vma_iter_config(vmg->vmi, vmg->end, vmg->next->vm_end);
687 } else {
688 vma = vmg->target;
689 /* Note: vma iterator must be pointing to 'start'. */
690 vma_iter_config(vmg->vmi, vmg->start, vmg->end);
691 }
692
693 init_multi_vma_prep(&vp, vma, vmg);
694
695 if (vma_iter_prealloc(vmg->vmi, vma))
696 return -ENOMEM;
697
698 vma_prepare(&vp);
699 /*
700 * THP pages may need to do additional splits if we increase
701 * middle->vm_start.
702 */
703 vma_adjust_trans_huge(vma, vmg->start, vmg->end,
> 704 adj_middle ? vmg->middle : NULL);
705 vma_set_range(vma, vmg->start, vmg->end, vmg->pgoff);
706 vmg_adjust_set_range(vmg);
707 vma_iter_store(vmg->vmi, vmg->target);
708
709 vma_complete(&vp, vmg->vmi, vma->vm_mm);
710
711 return 0;
712 }
713
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Hi Lorenzo,
kernel test robot noticed the following build warnings:
[auto build test WARNING on akpm-mm/mm-everything]
url: https://github.com/intel-lab-lkp/linux/commits/Lorenzo-Stoakes/mm-simplify-vma-merge-structure-and-expand-comments/20250127-235322
base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link: https://lore.kernel.org/r/ef00aec42a892fe6ac9557b3a11f18f30a2e51b3.1737929364.git.lorenzo.stoakes%40oracle.com
patch subject: [PATCH 5/5] mm: completely abstract unnecessary adj_start calculation
config: hexagon-randconfig-002-20250128 (https://download.01.org/0day-ci/archive/20250128/202501280408.9NtSz2Lt-lkp@intel.com/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250128/202501280408.9NtSz2Lt-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202501280408.9NtSz2Lt-lkp@intel.com/
All warnings (new ones prefixed by >>):
>> mm/vma.c:518:50: warning: incompatible pointer to integer conversion passing 'void *' to parameter of type 'long' [-Wint-conversion]
vma_adjust_trans_huge(vma, vma->vm_start, addr, NULL);
^~~~
include/linux/stddef.h:8:14: note: expanded from macro 'NULL'
#define NULL ((void *)0)
^~~~~~~~~~~
include/linux/huge_mm.h:574:12: note: passing argument to parameter 'adjust_next' here
long adjust_next)
^
>> mm/vma.c:704:10: warning: incompatible pointer to integer conversion passing 'struct vm_area_struct *' to parameter of type 'long' [-Wint-conversion]
adj_middle ? vmg->middle : NULL);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/huge_mm.h:574:12: note: passing argument to parameter 'adjust_next' here
long adjust_next)
^
mm/vma.c:1141:41: warning: incompatible pointer to integer conversion passing 'void *' to parameter of type 'long' [-Wint-conversion]
vma_adjust_trans_huge(vma, start, end, NULL);
^~~~
include/linux/stddef.h:8:14: note: expanded from macro 'NULL'
#define NULL ((void *)0)
^~~~~~~~~~~
include/linux/huge_mm.h:574:12: note: passing argument to parameter 'adjust_next' here
long adjust_next)
^
3 warnings generated.
vim +518 mm/vma.c
459
460 /*
461 * __split_vma() bypasses sysctl_max_map_count checking. We use this where it
462 * has already been checked or doesn't make sense to fail.
463 * VMA Iterator will point to the original VMA.
464 */
465 static __must_check int
466 __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
467 unsigned long addr, int new_below)
468 {
469 struct vma_prepare vp;
470 struct vm_area_struct *new;
471 int err;
472
473 WARN_ON(vma->vm_start >= addr);
474 WARN_ON(vma->vm_end <= addr);
475
476 if (vma->vm_ops && vma->vm_ops->may_split) {
477 err = vma->vm_ops->may_split(vma, addr);
478 if (err)
479 return err;
480 }
481
482 new = vm_area_dup(vma);
483 if (!new)
484 return -ENOMEM;
485
486 if (new_below) {
487 new->vm_end = addr;
488 } else {
489 new->vm_start = addr;
490 new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
491 }
492
493 err = -ENOMEM;
494 vma_iter_config(vmi, new->vm_start, new->vm_end);
495 if (vma_iter_prealloc(vmi, new))
496 goto out_free_vma;
497
498 err = vma_dup_policy(vma, new);
499 if (err)
500 goto out_free_vmi;
501
502 err = anon_vma_clone(new, vma);
503 if (err)
504 goto out_free_mpol;
505
506 if (new->vm_file)
507 get_file(new->vm_file);
508
509 if (new->vm_ops && new->vm_ops->open)
510 new->vm_ops->open(new);
511
512 vma_start_write(vma);
513 vma_start_write(new);
514
515 init_vma_prep(&vp, vma);
516 vp.insert = new;
517 vma_prepare(&vp);
> 518 vma_adjust_trans_huge(vma, vma->vm_start, addr, NULL);
519
520 if (new_below) {
521 vma->vm_start = addr;
522 vma->vm_pgoff += (addr - new->vm_start) >> PAGE_SHIFT;
523 } else {
524 vma->vm_end = addr;
525 }
526
527 /* vma_complete stores the new vma */
528 vma_complete(&vp, vmi, vma->vm_mm);
529 validate_mm(vma->vm_mm);
530
531 /* Success. */
532 if (new_below)
533 vma_next(vmi);
534 else
535 vma_prev(vmi);
536
537 return 0;
538
539 out_free_mpol:
540 mpol_put(vma_policy(new));
541 out_free_vmi:
542 vma_iter_free(vmi);
543 out_free_vma:
544 vm_area_free(new);
545 return err;
546 }
547
548 /*
549 * Split a vma into two pieces at address 'addr', a new vma is allocated
550 * either for the first part or the tail.
551 */
552 static int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
553 unsigned long addr, int new_below)
554 {
555 if (vma->vm_mm->map_count >= sysctl_max_map_count)
556 return -ENOMEM;
557
558 return __split_vma(vmi, vma, addr, new_below);
559 }
560
561 /*
562 * dup_anon_vma() - Helper function to duplicate anon_vma
563 * @dst: The destination VMA
564 * @src: The source VMA
565 * @dup: Pointer to the destination VMA when successful.
566 *
567 * Returns: 0 on success.
568 */
569 static int dup_anon_vma(struct vm_area_struct *dst,
570 struct vm_area_struct *src, struct vm_area_struct **dup)
571 {
572 /*
573 * Easily overlooked: when mprotect shifts the boundary, make sure the
574 * expanding vma has anon_vma set if the shrinking vma had, to cover any
575 * anon pages imported.
576 */
577 if (src->anon_vma && !dst->anon_vma) {
578 int ret;
579
580 vma_assert_write_locked(dst);
581 dst->anon_vma = src->anon_vma;
582 ret = anon_vma_clone(dst, src);
583 if (ret)
584 return ret;
585
586 *dup = dst;
587 }
588
589 return 0;
590 }
591
592 #ifdef CONFIG_DEBUG_VM_MAPLE_TREE
593 void validate_mm(struct mm_struct *mm)
594 {
595 int bug = 0;
596 int i = 0;
597 struct vm_area_struct *vma;
598 VMA_ITERATOR(vmi, mm, 0);
599
600 mt_validate(&mm->mm_mt);
601 for_each_vma(vmi, vma) {
602 #ifdef CONFIG_DEBUG_VM_RB
603 struct anon_vma *anon_vma = vma->anon_vma;
604 struct anon_vma_chain *avc;
605 #endif
606 unsigned long vmi_start, vmi_end;
607 bool warn = 0;
608
609 vmi_start = vma_iter_addr(&vmi);
610 vmi_end = vma_iter_end(&vmi);
611 if (VM_WARN_ON_ONCE_MM(vma->vm_end != vmi_end, mm))
612 warn = 1;
613
614 if (VM_WARN_ON_ONCE_MM(vma->vm_start != vmi_start, mm))
615 warn = 1;
616
617 if (warn) {
618 pr_emerg("issue in %s\n", current->comm);
619 dump_stack();
620 dump_vma(vma);
621 pr_emerg("tree range: %px start %lx end %lx\n", vma,
622 vmi_start, vmi_end - 1);
623 vma_iter_dump_tree(&vmi);
624 }
625
626 #ifdef CONFIG_DEBUG_VM_RB
627 if (anon_vma) {
628 anon_vma_lock_read(anon_vma);
629 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
630 anon_vma_interval_tree_verify(avc);
631 anon_vma_unlock_read(anon_vma);
632 }
633 #endif
634 /* Check for a infinite loop */
635 if (++i > mm->map_count + 10) {
636 i = -1;
637 break;
638 }
639 }
640 if (i != mm->map_count) {
641 pr_emerg("map_count %d vma iterator %d\n", mm->map_count, i);
642 bug = 1;
643 }
644 VM_BUG_ON_MM(bug, mm);
645 }
646 #endif /* CONFIG_DEBUG_VM_MAPLE_TREE */
647
648 /*
649 * Based on the vmg flag indicating whether we need to adjust the vm_start field
650 * for the middle or next VMA, we calculate what the range of the newly adjusted
651 * VMA ought to be, and set the VMA's range accordingly.
652 */
653 static void vmg_adjust_set_range(struct vma_merge_struct *vmg)
654 {
655 unsigned long flags = vmg->merge_flags;
656 struct vm_area_struct *adjust;
657 pgoff_t pgoff;
658
659 if (flags & __VMG_FLAG_ADJUST_MIDDLE_START) {
660 adjust = vmg->middle;
661 pgoff = adjust->vm_pgoff + PHYS_PFN(vmg->end - adjust->vm_start);
662 } else if (flags & __VMG_FLAG_ADJUST_NEXT_START) {
663 adjust = vmg->next;
664 pgoff = adjust->vm_pgoff - PHYS_PFN(adjust->vm_start - vmg->end);
665 } else {
666 return;
667 }
668
669 vma_set_range(adjust, vmg->end, adjust->vm_end, pgoff);
670 }
671
672 /*
673 * Actually perform the VMA merge operation.
674 *
675 * On success, returns the merged VMA. Otherwise returns NULL.
676 */
677 static int commit_merge(struct vma_merge_struct *vmg)
678 {
679 struct vm_area_struct *vma;
680 struct vma_prepare vp;
681 bool adj_middle = vmg->merge_flags & __VMG_FLAG_ADJUST_MIDDLE_START;
682
683 if (vmg->merge_flags & __VMG_FLAG_ADJUST_NEXT_START) {
684 /* In this case we manipulate middle and return next. */
685 vma = vmg->middle;
686 vma_iter_config(vmg->vmi, vmg->end, vmg->next->vm_end);
687 } else {
688 vma = vmg->target;
689 /* Note: vma iterator must be pointing to 'start'. */
690 vma_iter_config(vmg->vmi, vmg->start, vmg->end);
691 }
692
693 init_multi_vma_prep(&vp, vma, vmg);
694
695 if (vma_iter_prealloc(vmg->vmi, vma))
696 return -ENOMEM;
697
698 vma_prepare(&vp);
699 /*
700 * THP pages may need to do additional splits if we increase
701 * middle->vm_start.
702 */
703 vma_adjust_trans_huge(vma, vmg->start, vmg->end,
> 704 adj_middle ? vmg->middle : NULL);
705 vma_set_range(vma, vmg->start, vmg->end, vmg->pgoff);
706 vmg_adjust_set_range(vmg);
707 vma_iter_store(vmg->vmi, vmg->target);
708
709 vma_complete(&vp, vmg->vmi, vma->vm_mm);
710
711 return 0;
712 }
713
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Hi Lorenzo,
kernel test robot noticed the following build errors:
[auto build test ERROR on akpm-mm/mm-everything]
url: https://github.com/intel-lab-lkp/linux/commits/Lorenzo-Stoakes/mm-simplify-vma-merge-structure-and-expand-comments/20250127-235322
base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link: https://lore.kernel.org/r/ef00aec42a892fe6ac9557b3a11f18f30a2e51b3.1737929364.git.lorenzo.stoakes%40oracle.com
patch subject: [PATCH 5/5] mm: completely abstract unnecessary adj_start calculation
config: hexagon-randconfig-001-20250128 (https://download.01.org/0day-ci/archive/20250128/202501280337.7bKYRAYQ-lkp@intel.com/config)
compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project 19306351a2c45e266fa11b41eb1362b20b6ca56d)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250128/202501280337.7bKYRAYQ-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202501280337.7bKYRAYQ-lkp@intel.com/
All errors (new ones prefixed by >>):
In file included from mm/vma.c:7:
In file included from mm/vma_internal.h:29:
include/linux/mm_inline.h:47:41: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
47 | __mod_lruvec_state(lruvec, NR_LRU_BASE + lru, nr_pages);
| ~~~~~~~~~~~ ^ ~~~
include/linux/mm_inline.h:49:22: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
49 | NR_ZONE_LRU_BASE + lru, nr_pages);
| ~~~~~~~~~~~~~~~~ ^ ~~~
>> mm/vma.c:518:50: error: incompatible pointer to integer conversion passing 'void *' to parameter of type 'long' [-Wint-conversion]
518 | vma_adjust_trans_huge(vma, vma->vm_start, addr, NULL);
| ^~~~
include/linux/stddef.h:8:14: note: expanded from macro 'NULL'
8 | #define NULL ((void *)0)
| ^~~~~~~~~~~
include/linux/huge_mm.h:574:12: note: passing argument to parameter 'adjust_next' here
574 | long adjust_next)
| ^
>> mm/vma.c:704:10: error: incompatible pointer to integer conversion passing 'struct vm_area_struct *' to parameter of type 'long' [-Wint-conversion]
704 | adj_middle ? vmg->middle : NULL);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/huge_mm.h:574:12: note: passing argument to parameter 'adjust_next' here
574 | long adjust_next)
| ^
mm/vma.c:1141:41: error: incompatible pointer to integer conversion passing 'void *' to parameter of type 'long' [-Wint-conversion]
1141 | vma_adjust_trans_huge(vma, start, end, NULL);
| ^~~~
include/linux/stddef.h:8:14: note: expanded from macro 'NULL'
8 | #define NULL ((void *)0)
| ^~~~~~~~~~~
include/linux/huge_mm.h:574:12: note: passing argument to parameter 'adjust_next' here
574 | long adjust_next)
| ^
2 warnings and 3 errors generated.
vim +518 mm/vma.c
459
460 /*
461 * __split_vma() bypasses sysctl_max_map_count checking. We use this where it
462 * has already been checked or doesn't make sense to fail.
463 * VMA Iterator will point to the original VMA.
464 */
465 static __must_check int
466 __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
467 unsigned long addr, int new_below)
468 {
469 struct vma_prepare vp;
470 struct vm_area_struct *new;
471 int err;
472
473 WARN_ON(vma->vm_start >= addr);
474 WARN_ON(vma->vm_end <= addr);
475
476 if (vma->vm_ops && vma->vm_ops->may_split) {
477 err = vma->vm_ops->may_split(vma, addr);
478 if (err)
479 return err;
480 }
481
482 new = vm_area_dup(vma);
483 if (!new)
484 return -ENOMEM;
485
486 if (new_below) {
487 new->vm_end = addr;
488 } else {
489 new->vm_start = addr;
490 new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
491 }
492
493 err = -ENOMEM;
494 vma_iter_config(vmi, new->vm_start, new->vm_end);
495 if (vma_iter_prealloc(vmi, new))
496 goto out_free_vma;
497
498 err = vma_dup_policy(vma, new);
499 if (err)
500 goto out_free_vmi;
501
502 err = anon_vma_clone(new, vma);
503 if (err)
504 goto out_free_mpol;
505
506 if (new->vm_file)
507 get_file(new->vm_file);
508
509 if (new->vm_ops && new->vm_ops->open)
510 new->vm_ops->open(new);
511
512 vma_start_write(vma);
513 vma_start_write(new);
514
515 init_vma_prep(&vp, vma);
516 vp.insert = new;
517 vma_prepare(&vp);
> 518 vma_adjust_trans_huge(vma, vma->vm_start, addr, NULL);
519
520 if (new_below) {
521 vma->vm_start = addr;
522 vma->vm_pgoff += (addr - new->vm_start) >> PAGE_SHIFT;
523 } else {
524 vma->vm_end = addr;
525 }
526
527 /* vma_complete stores the new vma */
528 vma_complete(&vp, vmi, vma->vm_mm);
529 validate_mm(vma->vm_mm);
530
531 /* Success. */
532 if (new_below)
533 vma_next(vmi);
534 else
535 vma_prev(vmi);
536
537 return 0;
538
539 out_free_mpol:
540 mpol_put(vma_policy(new));
541 out_free_vmi:
542 vma_iter_free(vmi);
543 out_free_vma:
544 vm_area_free(new);
545 return err;
546 }
547
548 /*
549 * Split a vma into two pieces at address 'addr', a new vma is allocated
550 * either for the first part or the tail.
551 */
552 static int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
553 unsigned long addr, int new_below)
554 {
555 if (vma->vm_mm->map_count >= sysctl_max_map_count)
556 return -ENOMEM;
557
558 return __split_vma(vmi, vma, addr, new_below);
559 }
560
561 /*
562 * dup_anon_vma() - Helper function to duplicate anon_vma
563 * @dst: The destination VMA
564 * @src: The source VMA
565 * @dup: Pointer to the destination VMA when successful.
566 *
567 * Returns: 0 on success.
568 */
569 static int dup_anon_vma(struct vm_area_struct *dst,
570 struct vm_area_struct *src, struct vm_area_struct **dup)
571 {
572 /*
573 * Easily overlooked: when mprotect shifts the boundary, make sure the
574 * expanding vma has anon_vma set if the shrinking vma had, to cover any
575 * anon pages imported.
576 */
577 if (src->anon_vma && !dst->anon_vma) {
578 int ret;
579
580 vma_assert_write_locked(dst);
581 dst->anon_vma = src->anon_vma;
582 ret = anon_vma_clone(dst, src);
583 if (ret)
584 return ret;
585
586 *dup = dst;
587 }
588
589 return 0;
590 }
591
592 #ifdef CONFIG_DEBUG_VM_MAPLE_TREE
593 void validate_mm(struct mm_struct *mm)
594 {
595 int bug = 0;
596 int i = 0;
597 struct vm_area_struct *vma;
598 VMA_ITERATOR(vmi, mm, 0);
599
600 mt_validate(&mm->mm_mt);
601 for_each_vma(vmi, vma) {
602 #ifdef CONFIG_DEBUG_VM_RB
603 struct anon_vma *anon_vma = vma->anon_vma;
604 struct anon_vma_chain *avc;
605 #endif
606 unsigned long vmi_start, vmi_end;
607 bool warn = 0;
608
609 vmi_start = vma_iter_addr(&vmi);
610 vmi_end = vma_iter_end(&vmi);
611 if (VM_WARN_ON_ONCE_MM(vma->vm_end != vmi_end, mm))
612 warn = 1;
613
614 if (VM_WARN_ON_ONCE_MM(vma->vm_start != vmi_start, mm))
615 warn = 1;
616
617 if (warn) {
618 pr_emerg("issue in %s\n", current->comm);
619 dump_stack();
620 dump_vma(vma);
621 pr_emerg("tree range: %px start %lx end %lx\n", vma,
622 vmi_start, vmi_end - 1);
623 vma_iter_dump_tree(&vmi);
624 }
625
626 #ifdef CONFIG_DEBUG_VM_RB
627 if (anon_vma) {
628 anon_vma_lock_read(anon_vma);
629 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
630 anon_vma_interval_tree_verify(avc);
631 anon_vma_unlock_read(anon_vma);
632 }
633 #endif
634 /* Check for a infinite loop */
635 if (++i > mm->map_count + 10) {
636 i = -1;
637 break;
638 }
639 }
640 if (i != mm->map_count) {
641 pr_emerg("map_count %d vma iterator %d\n", mm->map_count, i);
642 bug = 1;
643 }
644 VM_BUG_ON_MM(bug, mm);
645 }
646 #endif /* CONFIG_DEBUG_VM_MAPLE_TREE */
647
648 /*
649 * Based on the vmg flag indicating whether we need to adjust the vm_start field
650 * for the middle or next VMA, we calculate what the range of the newly adjusted
651 * VMA ought to be, and set the VMA's range accordingly.
652 */
653 static void vmg_adjust_set_range(struct vma_merge_struct *vmg)
654 {
655 unsigned long flags = vmg->merge_flags;
656 struct vm_area_struct *adjust;
657 pgoff_t pgoff;
658
659 if (flags & __VMG_FLAG_ADJUST_MIDDLE_START) {
660 adjust = vmg->middle;
661 pgoff = adjust->vm_pgoff + PHYS_PFN(vmg->end - adjust->vm_start);
662 } else if (flags & __VMG_FLAG_ADJUST_NEXT_START) {
663 adjust = vmg->next;
664 pgoff = adjust->vm_pgoff - PHYS_PFN(adjust->vm_start - vmg->end);
665 } else {
666 return;
667 }
668
669 vma_set_range(adjust, vmg->end, adjust->vm_end, pgoff);
670 }
671
672 /*
673 * Actually perform the VMA merge operation.
674 *
675 * On success, returns the merged VMA. Otherwise returns NULL.
676 */
677 static int commit_merge(struct vma_merge_struct *vmg)
678 {
679 struct vm_area_struct *vma;
680 struct vma_prepare vp;
681 bool adj_middle = vmg->merge_flags & __VMG_FLAG_ADJUST_MIDDLE_START;
682
683 if (vmg->merge_flags & __VMG_FLAG_ADJUST_NEXT_START) {
684 /* In this case we manipulate middle and return next. */
685 vma = vmg->middle;
686 vma_iter_config(vmg->vmi, vmg->end, vmg->next->vm_end);
687 } else {
688 vma = vmg->target;
689 /* Note: vma iterator must be pointing to 'start'. */
690 vma_iter_config(vmg->vmi, vmg->start, vmg->end);
691 }
692
693 init_multi_vma_prep(&vp, vma, vmg);
694
695 if (vma_iter_prealloc(vmg->vmi, vma))
696 return -ENOMEM;
697
698 vma_prepare(&vp);
699 /*
700 * THP pages may need to do additional splits if we increase
701 * middle->vm_start.
702 */
703 vma_adjust_trans_huge(vma, vmg->start, vmg->end,
> 704 adj_middle ? vmg->middle : NULL);
705 vma_set_range(vma, vmg->start, vmg->end, vmg->pgoff);
706 vmg_adjust_set_range(vmg);
707 vma_iter_store(vmg->vmi, vmg->target);
708
709 vma_complete(&vp, vmg->vmi, vma->vm_mm);
710
711 return 0;
712 }
713
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Hi Lorenzo,
kernel test robot noticed the following build warnings:
[auto build test WARNING on akpm-mm/mm-everything]
url: https://github.com/intel-lab-lkp/linux/commits/Lorenzo-Stoakes/mm-simplify-vma-merge-structure-and-expand-comments/20250127-235322
base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link: https://lore.kernel.org/r/ef00aec42a892fe6ac9557b3a11f18f30a2e51b3.1737929364.git.lorenzo.stoakes%40oracle.com
patch subject: [PATCH 5/5] mm: completely abstract unnecessary adj_start calculation
config: um-randconfig-001-20250128 (https://download.01.org/0day-ci/archive/20250128/202501280232.qYHi6Rkt-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250128/202501280232.qYHi6Rkt-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202501280232.qYHi6Rkt-lkp@intel.com/
All warnings (new ones prefixed by >>):
In file included from include/uapi/linux/posix_types.h:5,
from include/uapi/linux/types.h:14,
from include/linux/types.h:6,
from include/linux/kasan-checks.h:5,
from include/asm-generic/rwonce.h:26,
from ./arch/x86/include/generated/asm/rwonce.h:1,
from include/linux/compiler.h:339,
from include/linux/array_size.h:5,
from include/linux/kernel.h:16,
from include/linux/backing-dev.h:12,
from mm/vma_internal.h:12,
from mm/vma.c:7:
mm/vma.c: In function '__split_vma':
>> include/linux/stddef.h:8:14: warning: passing argument 4 of 'vma_adjust_trans_huge' makes integer from pointer without a cast [-Wint-conversion]
8 | #define NULL ((void *)0)
| ^~~~~~~~~~~
| |
| void *
mm/vma.c:518:57: note: in expansion of macro 'NULL'
518 | vma_adjust_trans_huge(vma, vma->vm_start, addr, NULL);
| ^~~~
In file included from include/linux/mm.h:1133,
from arch/um/include/asm/tlbflush.h:9,
from arch/um/include/asm/cacheflush.h:4,
from include/linux/cacheflush.h:5,
from include/linux/highmem.h:8,
from include/linux/bvec.h:10,
from include/linux/blk_types.h:10,
from include/linux/writeback.h:13,
from include/linux/backing-dev.h:16:
include/linux/huge_mm.h:574:47: note: expected 'long int' but argument is of type 'void *'
574 | long adjust_next)
| ~~~~~^~~~~~~~~~~
mm/vma.c: In function 'commit_merge':
>> mm/vma.c:704:56: warning: passing argument 4 of 'vma_adjust_trans_huge' makes integer from pointer without a cast [-Wint-conversion]
704 | adj_middle ? vmg->middle : NULL);
include/linux/huge_mm.h:574:47: note: expected 'long int' but argument is of type 'struct vm_area_struct *'
574 | long adjust_next)
| ~~~~~^~~~~~~~~~~
mm/vma.c: In function 'vma_shrink':
>> include/linux/stddef.h:8:14: warning: passing argument 4 of 'vma_adjust_trans_huge' makes integer from pointer without a cast [-Wint-conversion]
8 | #define NULL ((void *)0)
| ^~~~~~~~~~~
| |
| void *
mm/vma.c:1141:48: note: in expansion of macro 'NULL'
1141 | vma_adjust_trans_huge(vma, start, end, NULL);
| ^~~~
include/linux/huge_mm.h:574:47: note: expected 'long int' but argument is of type 'void *'
574 | long adjust_next)
| ~~~~~^~~~~~~~~~~
vim +/vma_adjust_trans_huge +8 include/linux/stddef.h
^1da177e4c3f41 Linus Torvalds 2005-04-16 6
^1da177e4c3f41 Linus Torvalds 2005-04-16 7 #undef NULL
^1da177e4c3f41 Linus Torvalds 2005-04-16 @8 #define NULL ((void *)0)
6e218287432472 Richard Knutsson 2006-09-30 9
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
On Tue, Jan 28, 2025 at 02:50:55AM +0800, kernel test robot wrote:
> Hi Lorenzo,
>
> kernel test robot noticed the following build warnings:
>
> [auto build test WARNING on akpm-mm/mm-everything]
>
> url: https://github.com/intel-lab-lkp/linux/commits/Lorenzo-Stoakes/mm-simplify-vma-merge-structure-and-expand-comments/20250127-235322
> base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
> patch link: https://lore.kernel.org/r/ef00aec42a892fe6ac9557b3a11f18f30a2e51b3.1737929364.git.lorenzo.stoakes%40oracle.com
> patch subject: [PATCH 5/5] mm: completely abstract unnecessary adj_start calculation
> config: um-randconfig-001-20250128 (https://download.01.org/0day-ci/archive/20250128/202501280232.qYHi6Rkt-lkp@intel.com/config)
> compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250128/202501280232.qYHi6Rkt-lkp@intel.com/reproduce)
>
[snap]
Hm, this is actually only applicable in the case that
CONFIG_TRANSPARENT_HUGEPAGE is specified, I missed the stub.
Andrew - if this doesn't go for a respin before the merge window ends, I attach
a fix-patch which should resolve this.
Thanks!
----8<----
From 47cf78f1975133fea2862830b43ab9a6937fef78 Mon Sep 17 00:00:00 2001
From: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Date: Mon, 27 Jan 2025 19:56:13 +0000
Subject: [PATCH] fixup
---
include/linux/huge_mm.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 43f76b54b522..e1bea54820ff 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -571,7 +571,7 @@ static inline int madvise_collapse(struct vm_area_struct *vma,
static inline void vma_adjust_trans_huge(struct vm_area_struct *vma,
unsigned long start,
unsigned long end,
- long adjust_next)
+ struct vm_area_struct *next)
{
}
static inline int is_swap_pmd(pmd_t pmd)
--
2.48.0
On Tue, Jan 28, 2025 at 02:50:55AM +0800, kernel test robot wrote: > Hi Lorenzo, > > kernel test robot noticed the following build warnings: > > [auto build test WARNING on akpm-mm/mm-everything] > > url: https://github.com/intel-lab-lkp/linux/commits/Lorenzo-Stoakes/mm-simplify-vma-merge-structure-and-expand-comments/20250127-235322 > base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything > patch link: https://lore.kernel.org/r/ef00aec42a892fe6ac9557b3a11f18f30a2e51b3.1737929364.git.lorenzo.stoakes%40oracle.com > patch subject: [PATCH 5/5] mm: completely abstract unnecessary adj_start calculation > config: um-randconfig-001-20250128 (https://download.01.org/0day-ci/archive/20250128/202501280232.qYHi6Rkt-lkp@intel.com/config) > compiler: gcc-12 (Debian 12.2.0-14) 12.2.0 > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250128/202501280232.qYHi6Rkt-lkp@intel.com/reproduce) > > If you fix the issue in a separate patch/commit (i.e. not just a new version of > the same patch/commit), kindly add following tags > | Reported-by: kernel test robot <lkp@intel.com> > | Closes: https://lore.kernel.org/oe-kbuild-all/202501280232.qYHi6Rkt-lkp@intel.com/ > > All warnings (new ones prefixed by >>): > > In file included from include/uapi/linux/posix_types.h:5, > from include/uapi/linux/types.h:14, > from include/linux/types.h:6, > from include/linux/kasan-checks.h:5, > from include/asm-generic/rwonce.h:26, > from ./arch/x86/include/generated/asm/rwonce.h:1, > from include/linux/compiler.h:339, > from include/linux/array_size.h:5, > from include/linux/kernel.h:16, > from include/linux/backing-dev.h:12, > from mm/vma_internal.h:12, > from mm/vma.c:7: > mm/vma.c: In function '__split_vma': > >> include/linux/stddef.h:8:14: warning: passing argument 4 of 'vma_adjust_trans_huge' makes integer from pointer without a cast [-Wint-conversion] > 8 | #define NULL ((void *)0) > | ^~~~~~~~~~~ > | | > | void * > mm/vma.c:518:57: note: in expansion of macro 'NULL' > 518 | vma_adjust_trans_huge(vma, vma->vm_start, addr, NULL); > | ^~~~ > In file included from include/linux/mm.h:1133, > from arch/um/include/asm/tlbflush.h:9, > from arch/um/include/asm/cacheflush.h:4, > from include/linux/cacheflush.h:5, > from include/linux/highmem.h:8, > from include/linux/bvec.h:10, > from include/linux/blk_types.h:10, > from include/linux/writeback.h:13, > from include/linux/backing-dev.h:16: > include/linux/huge_mm.h:574:47: note: expected 'long int' but argument is of type 'void *' > 574 | long adjust_next) > | ~~~~~^~~~~~~~~~~ Doh! My bad. For some reason I didn't change the header, and my local compiles must have made this a warning only and had no problem with it... That'll teach me for disabling CONFIG_WERROR :) I'll fix that. Thanks! > mm/vma.c: In function 'commit_merge': > >> mm/vma.c:704:56: warning: passing argument 4 of 'vma_adjust_trans_huge' makes integer from pointer without a cast [-Wint-conversion] > 704 | adj_middle ? vmg->middle : NULL); > include/linux/huge_mm.h:574:47: note: expected 'long int' but argument is of type 'struct vm_area_struct *' > 574 | long adjust_next) > | ~~~~~^~~~~~~~~~~ > mm/vma.c: In function 'vma_shrink': > >> include/linux/stddef.h:8:14: warning: passing argument 4 of 'vma_adjust_trans_huge' makes integer from pointer without a cast [-Wint-conversion] > 8 | #define NULL ((void *)0) > | ^~~~~~~~~~~ > | | > | void * > mm/vma.c:1141:48: note: in expansion of macro 'NULL' > 1141 | vma_adjust_trans_huge(vma, start, end, NULL); > | ^~~~ > include/linux/huge_mm.h:574:47: note: expected 'long int' but argument is of type 'void *' > 574 | long adjust_next) > | ~~~~~^~~~~~~~~~~ > > > vim +/vma_adjust_trans_huge +8 include/linux/stddef.h > > ^1da177e4c3f41 Linus Torvalds 2005-04-16 6 > ^1da177e4c3f41 Linus Torvalds 2005-04-16 7 #undef NULL > ^1da177e4c3f41 Linus Torvalds 2005-04-16 @8 #define NULL ((void *)0) > 6e218287432472 Richard Knutsson 2006-09-30 9 > > -- > 0-DAY CI Kernel Test Service > https://github.com/intel/lkp-tests/wiki
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