[PATCH 5/9] mm/madvise: define and use madvise_behavior struct for madvise_do_behavior()

SeongJae Park
2025-03-10T17:23:29Z

To implement batched tlb flushes for MADV_DONTNEED[_LOCKED] and
MADV_FREE, an mmu_gather object in addition to the behavior integer need
to be passed to the internal logics. Using a struct can make it easy
without increasing the number of parameters of all code paths towards
the internal logic. Define a struct for the purpose and use it on the
code path that starts from madvise_do_behavior() and ends on
madvise_dontneed_free().

Signed-off-by: SeongJae Park <sj@kernel.org>
---
mm/madvise.c | 36 ++++++++++++++++++++++++------------
1 file changed, 24 insertions(+), 12 deletions(-)

diff --git a/mm/madvise.c b/mm/madvise.c
index 469c25690a0e..ba2a78795207 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -890,11 +890,16 @@ static bool madvise_dontneed_free_valid_vma(struct vm_area_struct *vma,
return true;
}

+struct madvise_behavior {
+ int behavior;
+};
+
static long madvise_dontneed_free(struct vm_area_struct *vma,
struct vm_area_struct **prev,
unsigned long start, unsigned long end,
- int behavior)
+ struct madvise_behavior *madv_behavior)
{
+ int behavior = madv_behavior->behavior;
struct mm_struct *mm = vma->vm_mm;

*prev = vma;
@@ -1249,8 +1254,10 @@ static long madvise_guard_remove(struct vm_area_struct *vma,
static int madvise_vma_behavior(struct vm_area_struct *vma,
struct vm_area_struct **prev,
unsigned long start, unsigned long end,
- unsigned long behavior)
+ void *behavior_arg)
{
+ struct madvise_behavior *arg = behavior_arg;
+ int behavior = arg->behavior;
int error;
struct anon_vma_name *anon_name;
unsigned long new_flags = vma->vm_flags;
@@ -1270,7 +1277,7 @@ static int madvise_vma_behavior(struct vm_area_struct *vma,
case MADV_FREE:
case MADV_DONTNEED:
case MADV_DONTNEED_LOCKED:
- return madvise_dontneed_free(vma, prev, start, end, behavior);
+ return madvise_dontneed_free(vma, prev, start, end, arg);
case MADV_NORMAL:
new_flags = new_flags & ~VM_RAND_READ & ~VM_SEQ_READ;
break;
@@ -1487,10 +1494,10 @@ static bool process_madvise_remote_valid(int behavior)
*/
static
int madvise_walk_vmas(struct mm_struct *mm, unsigned long start,
- unsigned long end, unsigned long arg,
+ unsigned long end, void *arg,
int (*visit)(struct vm_area_struct *vma,
struct vm_area_struct **prev, unsigned long start,
- unsigned long end, unsigned long arg))
+ unsigned long end, void *arg))
{
struct vm_area_struct *vma;
struct vm_area_struct *prev;
@@ -1548,7 +1555,7 @@ int madvise_walk_vmas(struct mm_struct *mm, unsigned long start,
static int madvise_vma_anon_name(struct vm_area_struct *vma,
struct vm_area_struct **prev,
unsigned long start, unsigned long end,
- unsigned long anon_name)
+ void *anon_name)
{
int error;

@@ -1557,7 +1564,7 @@ static int madvise_vma_anon_name(struct vm_area_struct *vma,
return -EBADF;

error = madvise_update_vma(vma, prev, start, end, vma->vm_flags,
- (struct anon_vma_name *)anon_name);
+ anon_name);

/*
* madvise() returns EAGAIN if kernel resources, such as
@@ -1589,7 +1596,7 @@ int madvise_set_anon_name(struct mm_struct *mm, unsigned long start,
if (end == start)
return 0;

- return madvise_walk_vmas(mm, start, end, (unsigned long)anon_name,
+ return madvise_walk_vmas(mm, start, end, anon_name,
madvise_vma_anon_name);
}
#endif /* CONFIG_ANON_VMA_NAME */
@@ -1673,8 +1680,10 @@ static bool is_madvise_populate(int behavior)
}

static int madvise_do_behavior(struct mm_struct *mm,
- unsigned long start, size_t len_in, int behavior)
+ unsigned long start, size_t len_in,
+ struct madvise_behavior *madv_behavior)
{
+ int behavior = madv_behavior->behavior;
struct blk_plug plug;
unsigned long end;
int error;
@@ -1688,7 +1697,7 @@ static int madvise_do_behavior(struct mm_struct *mm,
if (is_madvise_populate(behavior))
error = madvise_populate(mm, start, end, behavior);
else
- error = madvise_walk_vmas(mm, start, end, behavior,
+ error = madvise_walk_vmas(mm, start, end, madv_behavior,
madvise_vma_behavior);
blk_finish_plug(&plug);
return error;
@@ -1769,13 +1778,14 @@ static int madvise_do_behavior(struct mm_struct *mm,
int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int behavior)
{
int error;
+ struct madvise_behavior madv_behavior = {.behavior = behavior};

if (madvise_should_skip(start, len_in, behavior, &error))
return error;
error = madvise_lock(mm, behavior);
if (error)
return error;
- error = madvise_do_behavior(mm, start, len_in, behavior);
+ error = madvise_do_behavior(mm, start, len_in, &madv_behavior);
madvise_unlock(mm, behavior);

return error;
@@ -1792,6 +1802,7 @@ static ssize_t vector_madvise(struct mm_struct *mm, struct iov_iter *iter,
{
ssize_t ret = 0;
size_t total_len;
+ struct madvise_behavior madv_behavior = {.behavior = behavior};

total_len = iov_iter_count(iter);

@@ -1807,7 +1818,8 @@ static ssize_t vector_madvise(struct mm_struct *mm, struct iov_iter *iter,
if (madvise_should_skip(start, len_in, behavior, &error))
ret = error;
else
- ret = madvise_do_behavior(mm, start, len_in, behavior);
+ ret = madvise_do_behavior(mm, start, len_in,
+ &madv_behavior);
/*
* An madvise operation is attempting to restart the syscall,
* but we cannot proceed as it would not be correct to repeat
--
2.39.5