linux-kernel - [PATCH 2/5] mm/vmalloc: Extend __alloc_vmap

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Date:   Tue,  7 Jun 2022 11:34:46 +0200
From:   "Uladzislau Rezki (Sony)" <urezki@...il.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-mm@...ck.org, LKML <linux-kernel@...r.kernel.org>,
        Christoph Hellwig <hch@...radead.org>,
        Matthew Wilcox <willy@...radead.org>,
        Nicholas Piggin <npiggin@...il.com>,
        Uladzislau Rezki <urezki@...il.com>,
        Oleksiy Avramchenko <oleksiy.avramchenko@...y.com>
Subject: [PATCH 2/5] mm/vmalloc: Extend __alloc_vmap_area() with extra arguments

It implies that __alloc_vmap_area() allocates only from the
global vmap space, therefore a list-head and rb-tree, which
represent a free vmap space, are not passed as parameters to
this function and are accessed directly from this function.

Extend the __alloc_vmap_area() and other dependent functions
to have a possibility to allocate from different trees making
an interface common and not specific.

There is no functional change as a result of this patch.

Signed-off-by: Uladzislau Rezki (Sony) <urezki@...il.com>
---
 mm/vmalloc.c | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 0102d6d5fcdf..745e89eb6ca1 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1234,15 +1234,15 @@ is_within_this_va(struct vmap_area *va, unsigned long size,
  * overhead.
  */
 static __always_inline struct vmap_area *
-find_vmap_lowest_match(unsigned long size, unsigned long align,
-	unsigned long vstart, bool adjust_search_size)
+find_vmap_lowest_match(struct rb_root *root, unsigned long size,
+	unsigned long align, unsigned long vstart, bool adjust_search_size)
 {
 	struct vmap_area *va;
 	struct rb_node *node;
 	unsigned long length;
 
 	/* Start from the root. */
-	node = free_vmap_area_root.rb_node;
+	node = root->rb_node;
 
 	/* Adjust the search size for alignment overhead. */
 	length = adjust_search_size ? size + align - 1 : size;
@@ -1370,9 +1370,9 @@ classify_va_fit_type(struct vmap_area *va,
 }
 
 static __always_inline int
-adjust_va_to_fit_type(struct vmap_area *va,
-	unsigned long nva_start_addr, unsigned long size,
-	enum fit_type type)
+adjust_va_to_fit_type(struct rb_root *root, struct list_head *head,
+	struct vmap_area *va, unsigned long nva_start_addr,
+	unsigned long size, enum fit_type type)
 {
 	struct vmap_area *lva = NULL;
 
@@ -1384,7 +1384,7 @@ adjust_va_to_fit_type(struct vmap_area *va,
 		 * V      NVA      V
 		 * |---------------|
 		 */
-		unlink_va_augment(va, &free_vmap_area_root);
+		unlink_va_augment(va, root);
 		kmem_cache_free(vmap_area_cachep, va);
 	} else if (type == LE_FIT_TYPE) {
 		/*
@@ -1462,8 +1462,7 @@ adjust_va_to_fit_type(struct vmap_area *va,
 		augment_tree_propagate_from(va);
 
 		if (lva)	/* type == NE_FIT_TYPE */
-			insert_vmap_area_augment(lva, &va->rb_node,
-				&free_vmap_area_root, &free_vmap_area_list);
+			insert_vmap_area_augment(lva, &va->rb_node, root, head);
 	}
 
 	return 0;
@@ -1474,7 +1473,8 @@ adjust_va_to_fit_type(struct vmap_area *va,
  * Otherwise a vend is returned that indicates failure.
  */
 static __always_inline unsigned long
-__alloc_vmap_area(unsigned long size, unsigned long align,
+__alloc_vmap_area(struct rb_root *root, struct list_head *head,
+	unsigned long size, unsigned long align,
 	unsigned long vstart, unsigned long vend)
 {
 	bool adjust_search_size = true;
@@ -1495,7 +1495,7 @@ __alloc_vmap_area(unsigned long size, unsigned long align,
 	if (align <= PAGE_SIZE || (align > PAGE_SIZE && (vend - vstart) == size))
 		adjust_search_size = false;
 
-	va = find_vmap_lowest_match(size, align, vstart, adjust_search_size);
+	va = find_vmap_lowest_match(root, size, align, vstart, adjust_search_size);
 	if (unlikely(!va))
 		return vend;
 
@@ -1514,7 +1514,7 @@ __alloc_vmap_area(unsigned long size, unsigned long align,
 		return vend;
 
 	/* Update the free vmap_area. */
-	ret = adjust_va_to_fit_type(va, nva_start_addr, size, type);
+	ret = adjust_va_to_fit_type(root, head, va, nva_start_addr, size, type);
 	if (ret)
 		return vend;
 
@@ -1605,7 +1605,8 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
 
 retry:
 	preload_this_cpu_lock(&free_vmap_area_lock, gfp_mask, node);
-	addr = __alloc_vmap_area(size, align, vstart, vend);
+	addr = __alloc_vmap_area(&free_vmap_area_root, &free_vmap_area_list,
+		size, align, vstart, vend);
 	spin_unlock(&free_vmap_area_lock);
 
 	/*
@@ -3886,7 +3887,8 @@ struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets,
 			/* It is a BUG(), but trigger recovery instead. */
 			goto recovery;
 
-		ret = adjust_va_to_fit_type(va, start, size, type);
+		ret = adjust_va_to_fit_type(&free_vmap_area_root,
+				&free_vmap_area_list, va, start, size, type);
 		if (unlikely(ret))
 			goto recovery;
 
-- 
2.30.2