The patch titled
Subject: z3fold: protect handle reads
has been removed from the -mm tree. Its filename was
z3fold-protect-handle-reads.patch
This patch was dropped because it was folded into z3fold-add-inter-page-compaction.patch
------------------------------------------------------
From: Vitaly Wool <vitalywool@xxxxxxxxx>
Subject: z3fold: protect handle reads
We need to make sure slots are protected on reading a handle. Since
handles are modified by free_handle() which only takes slot rwlock, that
lock should be used when handles are read.
Link: http://lkml.kernel.org/r/20191127152345.8059852f60947686674d726d@xxxxxxxxx
Signed-off-by: Vitaly Wool <vitaly.vul@xxxxxxxx>
Cc: Dan Streetman <ddstreet@xxxxxxxx>
Cc: Henry Burns <henrywolfeburns@xxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/z3fold.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
--- a/mm/z3fold.c~z3fold-protect-handle-reads
+++ a/mm/z3fold.c
@@ -486,8 +486,12 @@ static unsigned long encode_handle(struc
/* only for LAST bud, returns zero otherwise */
static unsigned short handle_to_chunks(unsigned long handle)
{
- unsigned long addr = *(unsigned long *)handle;
+ struct z3fold_buddy_slots *slots = handle_to_slots(handle);
+ unsigned long addr;
+ read_lock(&slots->lock);
+ addr = *(unsigned long *)handle;
+ read_unlock(&slots->lock);
return (addr & ~PAGE_MASK) >> BUDDY_SHIFT;
}
@@ -499,10 +503,13 @@ static unsigned short handle_to_chunks(u
static enum buddy handle_to_buddy(unsigned long handle)
{
struct z3fold_header *zhdr;
+ struct z3fold_buddy_slots *slots = handle_to_slots(handle);
unsigned long addr;
+ read_lock(&slots->lock);
WARN_ON(handle & (1 << PAGE_HEADLESS));
addr = *(unsigned long *)handle;
+ read_unlock(&slots->lock);
zhdr = (struct z3fold_header *)(addr & PAGE_MASK);
return (addr - zhdr->first_num) & BUDDY_MASK;
}
_
Patches currently in -mm which might be from vitalywool@xxxxxxxxx are
z3fold-add-inter-page-compaction.patch
