GitHub-Mirror/linux-bl808
2
0
Fork 0
mirror of https://github.com/Fishwaldo/linux-bl808.git synced 2025-06-05 14:14:54 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

x86/mm/pat: Change free_memtype() to support shrinking case

Browse source 
Using mremap() to shrink the map size of a VM_PFNMAP range causes
the following error message, and leaves the pfn range allocated.

 x86/PAT: test:3493 freeing invalid memtype [mem 0x483200000-0x4863fffff]

This is because rbt_memtype_erase(), called from free_memtype()
with spin_lock held, only supports to free a whole memtype node in
memtype_rbroot.  Therefore, this patch changes rbt_memtype_erase()
to support a request that shrinks the size of a memtype node for
mremap().

memtype_rb_exact_match() is renamed to memtype_rb_match(), and
is enhanced to support EXACT_MATCH and END_MATCH in @match_type.
Since the memtype_rbroot tree allows overlapping ranges,
rbt_memtype_erase() checks with EXACT_MATCH first, i.e. free
a whole node for the munmap case.  If no such entry is found,
it then checks with END_MATCH, i.e. shrink the size of a node
from the end for the mremap case.

On the mremap case, rbt_memtype_erase() proceeds in two steps,
1) remove the node, and then 2) insert the updated node.  This
allows proper update of augmented values, subtree_max_end, in
the tree.

Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: stsp@list.ru
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1450832064-10093-3-git-send-email-toshi.kani@hpe.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Toshi Kani 2015-12-22 17:54:24 -07:00 • committed by Thomas Gleixner
parent d9fe4fab11
commit 2039e6acaf
2 changed files with 44 additions and 10 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
arch/x86/mm/pat.c
View file

@ -586,7 +586,7 @@ int free_memtype(u64 start, u64 end)
entry = rbt_memtype_erase(start, end);
spin_unlock(&memtype_lock);
if (!entry) {
if (IS_ERR(entry)) {
pr_info("x86/PAT: %s:%d freeing invalid memtype [mem %#010Lx-%#010Lx]\n",
current->comm, current->pid, start, end - 1);
return -EINVAL;

52
arch/x86/mm/pat_rbtree.c
View file

@ -98,8 +98,13 @@ static struct memtype *memtype_rb_lowest_match(struct rb_root *root,
return last_lower; /* Returns NULL if there is no overlap */
}
static struct memtype *memtype_rb_exact_match(struct rb_root *root,
u64 start, u64 end)
enum {
MEMTYPE_EXACT_MATCH = 0,
MEMTYPE_END_MATCH = 1
};
static struct memtype *memtype_rb_match(struct rb_root *root,
u64 start, u64 end, int match_type)
{
struct memtype *match;
@ -107,7 +112,12 @@ static struct memtype *memtype_rb_exact_match(struct rb_root *root,
while (match != NULL && match->start < end) {
struct rb_node *node;
if (match->start == start && match->end == end)
if ((match_type == MEMTYPE_EXACT_MATCH) &&
(match->start == start) && (match->end == end))
return match;
if ((match_type == MEMTYPE_END_MATCH) &&
(match->start < start) && (match->end == end))
return match;
node = rb_next(&match->rb);
@ -117,7 +127,7 @@ static struct memtype *memtype_rb_exact_match(struct rb_root *root,
match = NULL;
}
return NULL; /* Returns NULL if there is no exact match */
return NULL; /* Returns NULL if there is no match */
}
static int memtype_rb_check_conflict(struct rb_root *root,
@ -210,12 +220,36 @@ struct memtype *rbt_memtype_erase(u64 start, u64 end)
{
struct memtype *data;
data = memtype_rb_exact_match(&memtype_rbroot, start, end);
if (!data)
goto out;
/*
* Since the memtype_rbroot tree allows overlapping ranges,
* rbt_memtype_erase() checks with EXACT_MATCH first, i.e. free
* a whole node for the munmap case. If no such entry is found,
* it then checks with END_MATCH, i.e. shrink the size of a node
* from the end for the mremap case.
*/
data = memtype_rb_match(&memtype_rbroot, start, end,
MEMTYPE_EXACT_MATCH);
if (!data) {
data = memtype_rb_match(&memtype_rbroot, start, end,
MEMTYPE_END_MATCH);
if (!data)
return ERR_PTR(-EINVAL);
}
if (data->start == start) {
/* munmap: erase this node */
rb_erase_augmented(&data->rb, &memtype_rbroot,
&memtype_rb_augment_cb);
} else {
/* mremap: update the end value of this node */
rb_erase_augmented(&data->rb, &memtype_rbroot,
&memtype_rb_augment_cb);
data->end = start;
data->subtree_max_end = data->end;
memtype_rb_insert(&memtype_rbroot, data);
return NULL;
}
rb_erase_augmented(&data->rb, &memtype_rbroot, &memtype_rb_augment_cb);
out:
return data;
}