[PATCH v4 07/26] mm: Drop first_index/last_index in zap_details

From: Peter Xu
Date: Wed Jul 14 2021 - 18:21:43 EST


The first_index/last_index parameters in zap_details are actually only used in
unmap_mapping_range_tree(). At the meantime, this function is only called by
unmap_mapping_pages() once. Instead of passing these two variables through the
whole stack of page zapping code, remove them from zap_details and let them
simply be parameters of unmap_mapping_range_tree(), which is inlined.

Reviewed-by: Alistair Popple <apopple@xxxxxxxxxx>
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
---
include/linux/mm.h | 2 --
mm/memory.c | 29 ++++++++++++++++-------------
2 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 57453dba41b9..795b3cd643ca 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1720,8 +1720,6 @@ extern void user_shm_unlock(size_t, struct ucounts *);
*/
struct zap_details {
struct address_space *check_mapping; /* Check page->mapping if set */
- pgoff_t first_index; /* Lowest page->index to unmap */
- pgoff_t last_index; /* Highest page->index to unmap */
struct page *single_page; /* Locked page to be unmapped */
};

diff --git a/mm/memory.c b/mm/memory.c
index ba8033ca6682..4c269d7b3d83 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3322,20 +3322,20 @@ static void unmap_mapping_range_vma(struct vm_area_struct *vma,
}

static inline void unmap_mapping_range_tree(struct rb_root_cached *root,
+ pgoff_t first_index,
+ pgoff_t last_index,
struct zap_details *details)
{
struct vm_area_struct *vma;
pgoff_t vba, vea, zba, zea;

- vma_interval_tree_foreach(vma, root,
- details->first_index, details->last_index) {
-
+ vma_interval_tree_foreach(vma, root, first_index, last_index) {
vba = vma->vm_pgoff;
vea = vba + vma_pages(vma) - 1;
- zba = details->first_index;
+ zba = first_index;
if (zba < vba)
zba = vba;
- zea = details->last_index;
+ zea = last_index;
if (zea > vea)
zea = vea;

@@ -3361,18 +3361,21 @@ void unmap_mapping_page(struct page *page)
{
struct address_space *mapping = page->mapping;
struct zap_details details = { };
+ pgoff_t first_index, last_index;

VM_BUG_ON(!PageLocked(page));
VM_BUG_ON(PageTail(page));

+ first_index = page->index;
+ last_index = page->index + thp_nr_pages(page) - 1;
+
details.check_mapping = mapping;
- details.first_index = page->index;
- details.last_index = page->index + thp_nr_pages(page) - 1;
details.single_page = page;

i_mmap_lock_write(mapping);
if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root)))
- unmap_mapping_range_tree(&mapping->i_mmap, &details);
+ unmap_mapping_range_tree(&mapping->i_mmap, first_index,
+ last_index, &details);
i_mmap_unlock_write(mapping);
}

@@ -3391,17 +3394,17 @@ void unmap_mapping_page(struct page *page)
void unmap_mapping_pages(struct address_space *mapping, pgoff_t start,
pgoff_t nr, bool even_cows)
{
+ pgoff_t first_index = start, last_index = start + nr - 1;
struct zap_details details = { };

details.check_mapping = even_cows ? NULL : mapping;
- details.first_index = start;
- details.last_index = start + nr - 1;
- if (details.last_index < details.first_index)
- details.last_index = ULONG_MAX;
+ if (last_index < first_index)
+ last_index = ULONG_MAX;

i_mmap_lock_write(mapping);
if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root)))
- unmap_mapping_range_tree(&mapping->i_mmap, &details);
+ unmap_mapping_range_tree(&mapping->i_mmap, first_index,
+ last_index, &details);
i_mmap_unlock_write(mapping);
}

--
2.31.1