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authorLinus Torvalds <torvalds@linux-foundation.org>2020-01-23 11:37:19 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-01-23 11:37:19 -0800
commit4703d9119972bf586d2cca76ec6438f819ffa30e (patch)
treedcfa2b44c5b613252b974b42471f5220ca4e81b6 /lib
parent34597c85be987cc731a840fa0c9bb969c92bd986 (diff)
parent00ed452c210a0bc1ff3ee79e1ce6b199f00a0638 (diff)
Merge tag 'xarray-5.5' of git://git.infradead.org/users/willy/linux-dax
Pull XArray fixes from Matthew Wilcox: "Primarily bugfixes, mostly around handling index wrap-around correctly. A couple of doc fixes and adding missing APIs. I had an oops live on stage at linux.conf.au this year, and it turned out to be a bug in xas_find() which I can't prove isn't triggerable in the current codebase. Then in looking for the bug, I spotted two more bugs. The bots have had a few days to chew on this with no problems reported, and it passes the test-suite (which now has more tests to make sure these problems don't come back)" * tag 'xarray-5.5' of git://git.infradead.org/users/willy/linux-dax: XArray: Add xa_for_each_range XArray: Fix xas_find returning too many entries XArray: Fix xa_find_after with multi-index entries XArray: Fix infinite loop with entry at ULONG_MAX XArray: Add wrappers for nested spinlocks XArray: Improve documentation of search marks XArray: Fix xas_pause at ULONG_MAX
Diffstat (limited to 'lib')
-rw-r--r--lib/test_xarray.c78
-rw-r--r--lib/xarray.c41
2 files changed, 93 insertions, 26 deletions
diff --git a/lib/test_xarray.c b/lib/test_xarray.c
index 7df4f7f395bf..55c14e8c8859 100644
--- a/lib/test_xarray.c
+++ b/lib/test_xarray.c
@@ -2,6 +2,7 @@
/*
* test_xarray.c: Test the XArray API
* Copyright (c) 2017-2018 Microsoft Corporation
+ * Copyright (c) 2019-2020 Oracle
* Author: Matthew Wilcox <willy@infradead.org>
*/
@@ -902,28 +903,34 @@ static noinline void check_store_iter(struct xarray *xa)
XA_BUG_ON(xa, !xa_empty(xa));
}
-static noinline void check_multi_find(struct xarray *xa)
+static noinline void check_multi_find_1(struct xarray *xa, unsigned order)
{
#ifdef CONFIG_XARRAY_MULTI
+ unsigned long multi = 3 << order;
+ unsigned long next = 4 << order;
unsigned long index;
- xa_store_order(xa, 12, 2, xa_mk_value(12), GFP_KERNEL);
- XA_BUG_ON(xa, xa_store_index(xa, 16, GFP_KERNEL) != NULL);
+ xa_store_order(xa, multi, order, xa_mk_value(multi), GFP_KERNEL);
+ XA_BUG_ON(xa, xa_store_index(xa, next, GFP_KERNEL) != NULL);
+ XA_BUG_ON(xa, xa_store_index(xa, next + 1, GFP_KERNEL) != NULL);
index = 0;
XA_BUG_ON(xa, xa_find(xa, &index, ULONG_MAX, XA_PRESENT) !=
- xa_mk_value(12));
- XA_BUG_ON(xa, index != 12);
- index = 13;
+ xa_mk_value(multi));
+ XA_BUG_ON(xa, index != multi);
+ index = multi + 1;
XA_BUG_ON(xa, xa_find(xa, &index, ULONG_MAX, XA_PRESENT) !=
- xa_mk_value(12));
- XA_BUG_ON(xa, (index < 12) || (index >= 16));
+ xa_mk_value(multi));
+ XA_BUG_ON(xa, (index < multi) || (index >= next));
XA_BUG_ON(xa, xa_find_after(xa, &index, ULONG_MAX, XA_PRESENT) !=
- xa_mk_value(16));
- XA_BUG_ON(xa, index != 16);
-
- xa_erase_index(xa, 12);
- xa_erase_index(xa, 16);
+ xa_mk_value(next));
+ XA_BUG_ON(xa, index != next);
+ XA_BUG_ON(xa, xa_find_after(xa, &index, next, XA_PRESENT) != NULL);
+ XA_BUG_ON(xa, index != next);
+
+ xa_erase_index(xa, multi);
+ xa_erase_index(xa, next);
+ xa_erase_index(xa, next + 1);
XA_BUG_ON(xa, !xa_empty(xa));
#endif
}
@@ -1046,12 +1053,33 @@ static noinline void check_find_3(struct xarray *xa)
xa_destroy(xa);
}
+static noinline void check_find_4(struct xarray *xa)
+{
+ unsigned long index = 0;
+ void *entry;
+
+ xa_store_index(xa, ULONG_MAX, GFP_KERNEL);
+
+ entry = xa_find_after(xa, &index, ULONG_MAX, XA_PRESENT);
+ XA_BUG_ON(xa, entry != xa_mk_index(ULONG_MAX));
+
+ entry = xa_find_after(xa, &index, ULONG_MAX, XA_PRESENT);
+ XA_BUG_ON(xa, entry);
+
+ xa_erase_index(xa, ULONG_MAX);
+}
+
static noinline void check_find(struct xarray *xa)
{
+ unsigned i;
+
check_find_1(xa);
check_find_2(xa);
check_find_3(xa);
- check_multi_find(xa);
+ check_find_4(xa);
+
+ for (i = 2; i < 10; i++)
+ check_multi_find_1(xa, i);
check_multi_find_2(xa);
}
@@ -1132,6 +1160,27 @@ static noinline void check_move_tiny(struct xarray *xa)
XA_BUG_ON(xa, !xa_empty(xa));
}
+static noinline void check_move_max(struct xarray *xa)
+{
+ XA_STATE(xas, xa, 0);
+
+ xa_store_index(xa, ULONG_MAX, GFP_KERNEL);
+ rcu_read_lock();
+ XA_BUG_ON(xa, xas_find(&xas, ULONG_MAX) != xa_mk_index(ULONG_MAX));
+ XA_BUG_ON(xa, xas_find(&xas, ULONG_MAX) != NULL);
+ rcu_read_unlock();
+
+ xas_set(&xas, 0);
+ rcu_read_lock();
+ XA_BUG_ON(xa, xas_find(&xas, ULONG_MAX) != xa_mk_index(ULONG_MAX));
+ xas_pause(&xas);
+ XA_BUG_ON(xa, xas_find(&xas, ULONG_MAX) != NULL);
+ rcu_read_unlock();
+
+ xa_erase_index(xa, ULONG_MAX);
+ XA_BUG_ON(xa, !xa_empty(xa));
+}
+
static noinline void check_move_small(struct xarray *xa, unsigned long idx)
{
XA_STATE(xas, xa, 0);
@@ -1240,6 +1289,7 @@ static noinline void check_move(struct xarray *xa)
xa_destroy(xa);
check_move_tiny(xa);
+ check_move_max(xa);
for (i = 0; i < 16; i++)
check_move_small(xa, 1UL << i);
diff --git a/lib/xarray.c b/lib/xarray.c
index 1237c213f52b..1d9fab7db8da 100644
--- a/lib/xarray.c
+++ b/lib/xarray.c
@@ -1,7 +1,8 @@
// SPDX-License-Identifier: GPL-2.0+
/*
* XArray implementation
- * Copyright (c) 2017 Microsoft Corporation
+ * Copyright (c) 2017-2018 Microsoft Corporation
+ * Copyright (c) 2018-2020 Oracle
* Author: Matthew Wilcox <willy@infradead.org>
*/
@@ -967,6 +968,7 @@ void xas_pause(struct xa_state *xas)
if (xas_invalid(xas))
return;
+ xas->xa_node = XAS_RESTART;
if (node) {
unsigned int offset = xas->xa_offset;
while (++offset < XA_CHUNK_SIZE) {
@@ -974,10 +976,11 @@ void xas_pause(struct xa_state *xas)
break;
}
xas->xa_index += (offset - xas->xa_offset) << node->shift;
+ if (xas->xa_index == 0)
+ xas->xa_node = XAS_BOUNDS;
} else {
xas->xa_index++;
}
- xas->xa_node = XAS_RESTART;
}
EXPORT_SYMBOL_GPL(xas_pause);
@@ -1079,13 +1082,15 @@ void *xas_find(struct xa_state *xas, unsigned long max)
{
void *entry;
- if (xas_error(xas))
+ if (xas_error(xas) || xas->xa_node == XAS_BOUNDS)
return NULL;
+ if (xas->xa_index > max)
+ return set_bounds(xas);
if (!xas->xa_node) {
xas->xa_index = 1;
return set_bounds(xas);
- } else if (xas_top(xas->xa_node)) {
+ } else if (xas->xa_node == XAS_RESTART) {
entry = xas_load(xas);
if (entry || xas_not_node(xas->xa_node))
return entry;
@@ -1150,6 +1155,8 @@ void *xas_find_marked(struct xa_state *xas, unsigned long max, xa_mark_t mark)
if (xas_error(xas))
return NULL;
+ if (xas->xa_index > max)
+ goto max;
if (!xas->xa_node) {
xas->xa_index = 1;
@@ -1824,6 +1831,17 @@ void *xa_find(struct xarray *xa, unsigned long *indexp,
}
EXPORT_SYMBOL(xa_find);
+static bool xas_sibling(struct xa_state *xas)
+{
+ struct xa_node *node = xas->xa_node;
+ unsigned long mask;
+
+ if (!node)
+ return false;
+ mask = (XA_CHUNK_SIZE << node->shift) - 1;
+ return (xas->xa_index & mask) > (xas->xa_offset << node->shift);
+}
+
/**
* xa_find_after() - Search the XArray for a present entry.
* @xa: XArray.
@@ -1847,21 +1865,20 @@ void *xa_find_after(struct xarray *xa, unsigned long *indexp,
XA_STATE(xas, xa, *indexp + 1);
void *entry;
+ if (xas.xa_index == 0)
+ return NULL;
+
rcu_read_lock();
for (;;) {
if ((__force unsigned int)filter < XA_MAX_MARKS)
entry = xas_find_marked(&xas, max, filter);
else
entry = xas_find(&xas, max);
- if (xas.xa_node == XAS_BOUNDS)
+
+ if (xas_invalid(&xas))
break;
- if (xas.xa_shift) {
- if (xas.xa_index & ((1UL << xas.xa_shift) - 1))
- continue;
- } else {
- if (xas.xa_offset < (xas.xa_index & XA_CHUNK_MASK))
- continue;
- }
+ if (xas_sibling(&xas))
+ continue;
if (!xas_retry(&xas, entry))
break;
}