[PATCH 03/17] prmem: vmalloc support for dynamic allocation

From: Igor Stoppa
Date: Tue Oct 23 2018 - 17:36:09 EST

Prepare vmalloc for:
- tagging areas used for dynamic allocation of protected memory
- supporting various tags, related to the property that an area might have
- extrapolating the pool containing a given area
- chaining the areas in each pool
- extrapolating the area containing a given memory address

Since there is a list_head structure that is used only when disposing of
the allocation (the field purge_list), there are two pointers for the take,
before it comes the time of freeing the allocation.
To avoid increasing the size of the vmap_area structure, instead of
using a standard doubly linked list for tracking the chain of
vmap_areas, only one pointer is spent for this purpose, in a single
linked list, while the other is used to provide a direct connection to the
parent pool.

Signed-off-by: Igor Stoppa <igor.stoppa@xxxxxxxxxx>
CC: Michal Hocko <mhocko@xxxxxxxxxx>
CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
CC: Chintan Pandya <cpandya@xxxxxxxxxxxxxx>
CC: Joe Perches <joe@xxxxxxxxxxx>
CC: "Luis R. Rodriguez" <mcgrof@xxxxxxxxxx>
CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CC: Kate Stewart <kstewart@xxxxxxxxxxxxxxxxxxx>
CC: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
CC: Philippe Ombredanne <pombredanne@xxxxxxxx>
CC: linux-mm@xxxxxxxxx
CC: linux-kernel@xxxxxxxxxxxxxxx
include/linux/vmalloc.h | 12 +++++++++++-
mm/vmalloc.c | 2 +-
2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 398e9c95cd61..4d14a3b8089e 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -21,6 +21,9 @@ struct notifier_block; /* in notifier.h */
#define VM_UNINITIALIZED 0x00000020 /* vm_struct is not fully initialized */
#define VM_NO_GUARD 0x00000040 /* don't add guard page */
#define VM_KASAN 0x00000080 /* has allocated kasan shadow memory */
+#define VM_PMALLOC 0x00000100 /* pmalloc area - see docs */
+#define VM_PMALLOC_WR 0x00000200 /* pmalloc write rare area */
+#define VM_PMALLOC_PROTECTED 0x00000400 /* pmalloc protected area */
/* bits [20..32] reserved for arch specific ioremap internals */

@@ -48,7 +51,13 @@ struct vmap_area {
unsigned long flags;
struct rb_node rb_node; /* address sorted rbtree */
struct list_head list; /* address sorted list */
- struct llist_node purge_list; /* "lazy purge" list */
+ union {
+ struct llist_node purge_list; /* "lazy purge" list */
+ struct {
+ struct vmap_area *next;
+ struct pmalloc_pool *pool;
+ };
+ };
struct vm_struct *vm;
struct rcu_head rcu_head;
@@ -134,6 +143,7 @@ extern struct vm_struct *__get_vm_area_caller(unsigned long size,
const void *caller);
extern struct vm_struct *remove_vm_area(const void *addr);
extern struct vm_struct *find_vm_area(const void *addr);
+extern struct vmap_area *find_vmap_area(unsigned long addr);

extern int map_vm_area(struct vm_struct *area, pgprot_t prot,
struct page **pages);
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index a728fc492557..15850005fea5 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -742,7 +742,7 @@ static void free_unmap_vmap_area(struct vmap_area *va)

-static struct vmap_area *find_vmap_area(unsigned long addr)
+struct vmap_area *find_vmap_area(unsigned long addr)
struct vmap_area *va;