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authorLinus Torvalds <torvalds@linux-foundation.org>2018-11-24 18:44:01 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-11-24 18:44:01 -0800
commite2125dac22f2c9c66c412cd8e049a7305af59f73 (patch)
tree8584af248ee592622bd6e8a7f9cee0b041b784cc /lib
parente195ca6cb6f21633e56322d5aa11ed59cdb22fb2 (diff)
parentfffc9a260e38acec3187515738122a3ecb24ac90 (diff)
downloadlinux-e2125dac22f2c9c66c412cd8e049a7305af59f73.tar.bz2
Merge tag 'xarray-4.20-rc4' of git://git.infradead.org/users/willy/linux-dax
Pull XArray updates from Matthew Wilcox: "We found some bugs in the DAX conversion to XArray (and one bug which predated the XArray conversion). There were a couple of bugs in some of the higher-level functions, which aren't actually being called in today's kernel, but surfaced as a result of converting existing radix tree & IDR users over to the XArray. Some of the other changes to how the higher-level APIs work were also motivated by converting various users; again, they're not in use in today's kernel, so changing them has a low probability of introducing a bug. Dan can still trigger a bug in the DAX code with hot-offline/online, and we're working on tracking that down" * tag 'xarray-4.20-rc4' of git://git.infradead.org/users/willy/linux-dax: XArray tests: Add missing locking dax: Avoid losing wakeup in dax_lock_mapping_entry dax: Fix huge page faults dax: Fix dax_unlock_mapping_entry for PMD pages dax: Reinstate RCU protection of inode dax: Make sure the unlocking entry isn't locked dax: Remove optimisation from dax_lock_mapping_entry XArray tests: Correct some 64-bit assumptions XArray: Correct xa_store_range XArray: Fix Documentation XArray: Handle NULL pointers differently for allocation XArray: Unify xa_store and __xa_store XArray: Add xa_store_bh() and xa_store_irq() XArray: Turn xa_erase into an exported function XArray: Unify xa_cmpxchg and __xa_cmpxchg XArray: Regularise xa_reserve nilfs2: Use xa_erase_irq XArray: Export __xa_foo to non-GPL modules XArray: Fix xa_for_each with a single element at 0
Diffstat (limited to 'lib')
-rw-r--r--lib/test_xarray.c50
-rw-r--r--lib/xarray.c139
2 files changed, 107 insertions, 82 deletions
diff --git a/lib/test_xarray.c b/lib/test_xarray.c
index aa47754150ce..0598e86af8fc 100644
--- a/lib/test_xarray.c
+++ b/lib/test_xarray.c
@@ -208,15 +208,19 @@ static noinline void check_xa_mark_1(struct xarray *xa, unsigned long index)
XA_BUG_ON(xa, xa_get_mark(xa, i, XA_MARK_2));
/* We should see two elements in the array */
+ rcu_read_lock();
xas_for_each(&xas, entry, ULONG_MAX)
seen++;
+ rcu_read_unlock();
XA_BUG_ON(xa, seen != 2);
/* One of which is marked */
xas_set(&xas, 0);
seen = 0;
+ rcu_read_lock();
xas_for_each_marked(&xas, entry, ULONG_MAX, XA_MARK_0)
seen++;
+ rcu_read_unlock();
XA_BUG_ON(xa, seen != 1);
}
XA_BUG_ON(xa, xa_get_mark(xa, next, XA_MARK_0));
@@ -373,6 +377,12 @@ static noinline void check_reserve(struct xarray *xa)
xa_erase_index(xa, 12345678);
XA_BUG_ON(xa, !xa_empty(xa));
+ /* And so does xa_insert */
+ xa_reserve(xa, 12345678, GFP_KERNEL);
+ XA_BUG_ON(xa, xa_insert(xa, 12345678, xa_mk_value(12345678), 0) != 0);
+ xa_erase_index(xa, 12345678);
+ XA_BUG_ON(xa, !xa_empty(xa));
+
/* Can iterate through a reserved entry */
xa_store_index(xa, 5, GFP_KERNEL);
xa_reserve(xa, 6, GFP_KERNEL);
@@ -436,7 +446,9 @@ static noinline void check_multi_store_1(struct xarray *xa, unsigned long index,
XA_BUG_ON(xa, xa_load(xa, max) != NULL);
XA_BUG_ON(xa, xa_load(xa, min - 1) != NULL);
+ xas_lock(&xas);
XA_BUG_ON(xa, xas_store(&xas, xa_mk_value(min)) != xa_mk_value(index));
+ xas_unlock(&xas);
XA_BUG_ON(xa, xa_load(xa, min) != xa_mk_value(min));
XA_BUG_ON(xa, xa_load(xa, max - 1) != xa_mk_value(min));
XA_BUG_ON(xa, xa_load(xa, max) != NULL);
@@ -452,9 +464,11 @@ static noinline void check_multi_store_2(struct xarray *xa, unsigned long index,
XA_STATE(xas, xa, index);
xa_store_order(xa, index, order, xa_mk_value(0), GFP_KERNEL);
+ xas_lock(&xas);
XA_BUG_ON(xa, xas_store(&xas, xa_mk_value(1)) != xa_mk_value(0));
XA_BUG_ON(xa, xas.xa_index != index);
XA_BUG_ON(xa, xas_store(&xas, NULL) != xa_mk_value(1));
+ xas_unlock(&xas);
XA_BUG_ON(xa, !xa_empty(xa));
}
#endif
@@ -498,7 +512,7 @@ static noinline void check_multi_store(struct xarray *xa)
rcu_read_unlock();
/* We can erase multiple values with a single store */
- xa_store_order(xa, 0, 63, NULL, GFP_KERNEL);
+ xa_store_order(xa, 0, BITS_PER_LONG - 1, NULL, GFP_KERNEL);
XA_BUG_ON(xa, !xa_empty(xa));
/* Even when the first slot is empty but the others aren't */
@@ -702,7 +716,7 @@ static noinline void check_multi_find_2(struct xarray *xa)
}
}
-static noinline void check_find(struct xarray *xa)
+static noinline void check_find_1(struct xarray *xa)
{
unsigned long i, j, k;
@@ -748,6 +762,34 @@ static noinline void check_find(struct xarray *xa)
XA_BUG_ON(xa, xa_get_mark(xa, i, XA_MARK_0));
}
XA_BUG_ON(xa, !xa_empty(xa));
+}
+
+static noinline void check_find_2(struct xarray *xa)
+{
+ void *entry;
+ unsigned long i, j, index = 0;
+
+ xa_for_each(xa, entry, index, ULONG_MAX, XA_PRESENT) {
+ XA_BUG_ON(xa, true);
+ }
+
+ for (i = 0; i < 1024; i++) {
+ xa_store_index(xa, index, GFP_KERNEL);
+ j = 0;
+ index = 0;
+ xa_for_each(xa, entry, index, ULONG_MAX, XA_PRESENT) {
+ XA_BUG_ON(xa, xa_mk_value(index) != entry);
+ XA_BUG_ON(xa, index != j++);
+ }
+ }
+
+ xa_destroy(xa);
+}
+
+static noinline void check_find(struct xarray *xa)
+{
+ check_find_1(xa);
+ check_find_2(xa);
check_multi_find(xa);
check_multi_find_2(xa);
}
@@ -1067,7 +1109,7 @@ static noinline void check_store_range(struct xarray *xa)
__check_store_range(xa, 4095 + i, 4095 + j);
__check_store_range(xa, 4096 + i, 4096 + j);
__check_store_range(xa, 123456 + i, 123456 + j);
- __check_store_range(xa, UINT_MAX + i, UINT_MAX + j);
+ __check_store_range(xa, (1 << 24) + i, (1 << 24) + j);
}
}
}
@@ -1146,10 +1188,12 @@ static noinline void check_account(struct xarray *xa)
XA_STATE(xas, xa, 1 << order);
xa_store_order(xa, 0, order, xa, GFP_KERNEL);
+ rcu_read_lock();
xas_load(&xas);
XA_BUG_ON(xa, xas.xa_node->count == 0);
XA_BUG_ON(xa, xas.xa_node->count > (1 << order));
XA_BUG_ON(xa, xas.xa_node->nr_values != 0);
+ rcu_read_unlock();
xa_store_order(xa, 1 << order, order, xa_mk_value(1 << order),
GFP_KERNEL);
diff --git a/lib/xarray.c b/lib/xarray.c
index 8b176f009c08..bbacca576593 100644
--- a/lib/xarray.c
+++ b/lib/xarray.c
@@ -610,8 +610,8 @@ static int xas_expand(struct xa_state *xas, void *head)
* (see the xa_cmpxchg() implementation for an example).
*
* Return: If the slot already existed, returns the contents of this slot.
- * If the slot was newly created, returns NULL. If it failed to create the
- * slot, returns NULL and indicates the error in @xas.
+ * If the slot was newly created, returns %NULL. If it failed to create the
+ * slot, returns %NULL and indicates the error in @xas.
*/
static void *xas_create(struct xa_state *xas)
{
@@ -1334,44 +1334,31 @@ void *__xa_erase(struct xarray *xa, unsigned long index)
XA_STATE(xas, xa, index);
return xas_result(&xas, xas_store(&xas, NULL));
}
-EXPORT_SYMBOL_GPL(__xa_erase);
+EXPORT_SYMBOL(__xa_erase);
/**
- * xa_store() - Store this entry in the XArray.
+ * xa_erase() - Erase this entry from the XArray.
* @xa: XArray.
- * @index: Index into array.
- * @entry: New entry.
- * @gfp: Memory allocation flags.
+ * @index: Index of entry.
*
- * After this function returns, loads from this index will return @entry.
- * Storing into an existing multislot entry updates the entry of every index.
- * The marks associated with @index are unaffected unless @entry is %NULL.
+ * This function is the equivalent of calling xa_store() with %NULL as
+ * the third argument. The XArray does not need to allocate memory, so
+ * the user does not need to provide GFP flags.
*
- * Context: Process context. Takes and releases the xa_lock. May sleep
- * if the @gfp flags permit.
- * Return: The old entry at this index on success, xa_err(-EINVAL) if @entry
- * cannot be stored in an XArray, or xa_err(-ENOMEM) if memory allocation
- * failed.
+ * Context: Any context. Takes and releases the xa_lock.
+ * Return: The entry which used to be at this index.
*/
-void *xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp)
+void *xa_erase(struct xarray *xa, unsigned long index)
{
- XA_STATE(xas, xa, index);
- void *curr;
-
- if (WARN_ON_ONCE(xa_is_internal(entry)))
- return XA_ERROR(-EINVAL);
+ void *entry;
- do {
- xas_lock(&xas);
- curr = xas_store(&xas, entry);
- if (xa_track_free(xa) && entry)
- xas_clear_mark(&xas, XA_FREE_MARK);
- xas_unlock(&xas);
- } while (xas_nomem(&xas, gfp));
+ xa_lock(xa);
+ entry = __xa_erase(xa, index);
+ xa_unlock(xa);
- return xas_result(&xas, curr);
+ return entry;
}
-EXPORT_SYMBOL(xa_store);
+EXPORT_SYMBOL(xa_erase);
/**
* __xa_store() - Store this entry in the XArray.
@@ -1395,10 +1382,12 @@ void *__xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp)
if (WARN_ON_ONCE(xa_is_internal(entry)))
return XA_ERROR(-EINVAL);
+ if (xa_track_free(xa) && !entry)
+ entry = XA_ZERO_ENTRY;
do {
curr = xas_store(&xas, entry);
- if (xa_track_free(xa) && entry)
+ if (xa_track_free(xa))
xas_clear_mark(&xas, XA_FREE_MARK);
} while (__xas_nomem(&xas, gfp));
@@ -1407,45 +1396,33 @@ void *__xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp)
EXPORT_SYMBOL(__xa_store);
/**
- * xa_cmpxchg() - Conditionally replace an entry in the XArray.
+ * xa_store() - Store this entry in the XArray.
* @xa: XArray.
* @index: Index into array.
- * @old: Old value to test against.
- * @entry: New value to place in array.
+ * @entry: New entry.
* @gfp: Memory allocation flags.
*
- * If the entry at @index is the same as @old, replace it with @entry.
- * If the return value is equal to @old, then the exchange was successful.
+ * After this function returns, loads from this index will return @entry.
+ * Storing into an existing multislot entry updates the entry of every index.
+ * The marks associated with @index are unaffected unless @entry is %NULL.
*
- * Context: Process context. Takes and releases the xa_lock. May sleep
- * if the @gfp flags permit.
- * Return: The old value at this index or xa_err() if an error happened.
+ * Context: Any context. Takes and releases the xa_lock.
+ * May sleep if the @gfp flags permit.
+ * Return: The old entry at this index on success, xa_err(-EINVAL) if @entry
+ * cannot be stored in an XArray, or xa_err(-ENOMEM) if memory allocation
+ * failed.
*/
-void *xa_cmpxchg(struct xarray *xa, unsigned long index,
- void *old, void *entry, gfp_t gfp)
+void *xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp)
{
- XA_STATE(xas, xa, index);
void *curr;
- if (WARN_ON_ONCE(xa_is_internal(entry)))
- return XA_ERROR(-EINVAL);
-
- do {
- xas_lock(&xas);
- curr = xas_load(&xas);
- if (curr == XA_ZERO_ENTRY)
- curr = NULL;
- if (curr == old) {
- xas_store(&xas, entry);
- if (xa_track_free(xa) && entry)
- xas_clear_mark(&xas, XA_FREE_MARK);
- }
- xas_unlock(&xas);
- } while (xas_nomem(&xas, gfp));
+ xa_lock(xa);
+ curr = __xa_store(xa, index, entry, gfp);
+ xa_unlock(xa);
- return xas_result(&xas, curr);
+ return curr;
}
-EXPORT_SYMBOL(xa_cmpxchg);
+EXPORT_SYMBOL(xa_store);
/**
* __xa_cmpxchg() - Store this entry in the XArray.
@@ -1471,6 +1448,8 @@ void *__xa_cmpxchg(struct xarray *xa, unsigned long index,
if (WARN_ON_ONCE(xa_is_internal(entry)))
return XA_ERROR(-EINVAL);
+ if (xa_track_free(xa) && !entry)
+ entry = XA_ZERO_ENTRY;
do {
curr = xas_load(&xas);
@@ -1478,7 +1457,7 @@ void *__xa_cmpxchg(struct xarray *xa, unsigned long index,
curr = NULL;
if (curr == old) {
xas_store(&xas, entry);
- if (xa_track_free(xa) && entry)
+ if (xa_track_free(xa))
xas_clear_mark(&xas, XA_FREE_MARK);
}
} while (__xas_nomem(&xas, gfp));
@@ -1488,7 +1467,7 @@ void *__xa_cmpxchg(struct xarray *xa, unsigned long index,
EXPORT_SYMBOL(__xa_cmpxchg);
/**
- * xa_reserve() - Reserve this index in the XArray.
+ * __xa_reserve() - Reserve this index in the XArray.
* @xa: XArray.
* @index: Index into array.
* @gfp: Memory allocation flags.
@@ -1496,33 +1475,32 @@ EXPORT_SYMBOL(__xa_cmpxchg);
* Ensures there is somewhere to store an entry at @index in the array.
* If there is already something stored at @index, this function does
* nothing. If there was nothing there, the entry is marked as reserved.
- * Loads from @index will continue to see a %NULL pointer until a
- * subsequent store to @index.
+ * Loading from a reserved entry returns a %NULL pointer.
*
* If you do not use the entry that you have reserved, call xa_release()
* or xa_erase() to free any unnecessary memory.
*
- * Context: Process context. Takes and releases the xa_lock, IRQ or BH safe
- * if specified in XArray flags. May sleep if the @gfp flags permit.
+ * Context: Any context. Expects the xa_lock to be held on entry. May
+ * release the lock, sleep and reacquire the lock if the @gfp flags permit.
* Return: 0 if the reservation succeeded or -ENOMEM if it failed.
*/
-int xa_reserve(struct xarray *xa, unsigned long index, gfp_t gfp)
+int __xa_reserve(struct xarray *xa, unsigned long index, gfp_t gfp)
{
XA_STATE(xas, xa, index);
- unsigned int lock_type = xa_lock_type(xa);
void *curr;
do {
- xas_lock_type(&xas, lock_type);
curr = xas_load(&xas);
- if (!curr)
+ if (!curr) {
xas_store(&xas, XA_ZERO_ENTRY);
- xas_unlock_type(&xas, lock_type);
- } while (xas_nomem(&xas, gfp));
+ if (xa_track_free(xa))
+ xas_clear_mark(&xas, XA_FREE_MARK);
+ }
+ } while (__xas_nomem(&xas, gfp));
return xas_error(&xas);
}
-EXPORT_SYMBOL(xa_reserve);
+EXPORT_SYMBOL(__xa_reserve);
#ifdef CONFIG_XARRAY_MULTI
static void xas_set_range(struct xa_state *xas, unsigned long first,
@@ -1587,8 +1565,9 @@ void *xa_store_range(struct xarray *xa, unsigned long first,
do {
xas_lock(&xas);
if (entry) {
- unsigned int order = (last == ~0UL) ? 64 :
- ilog2(last + 1);
+ unsigned int order = BITS_PER_LONG;
+ if (last + 1)
+ order = __ffs(last + 1);
xas_set_order(&xas, last, order);
xas_create(&xas);
if (xas_error(&xas))
@@ -1662,7 +1641,7 @@ EXPORT_SYMBOL(__xa_alloc);
* @index: Index of entry.
* @mark: Mark number.
*
- * Attempting to set a mark on a NULL entry does not succeed.
+ * Attempting to set a mark on a %NULL entry does not succeed.
*
* Context: Any context. Expects xa_lock to be held on entry.
*/
@@ -1674,7 +1653,7 @@ void __xa_set_mark(struct xarray *xa, unsigned long index, xa_mark_t mark)
if (entry)
xas_set_mark(&xas, mark);
}
-EXPORT_SYMBOL_GPL(__xa_set_mark);
+EXPORT_SYMBOL(__xa_set_mark);
/**
* __xa_clear_mark() - Clear this mark on this entry while locked.
@@ -1692,7 +1671,7 @@ void __xa_clear_mark(struct xarray *xa, unsigned long index, xa_mark_t mark)
if (entry)
xas_clear_mark(&xas, mark);
}
-EXPORT_SYMBOL_GPL(__xa_clear_mark);
+EXPORT_SYMBOL(__xa_clear_mark);
/**
* xa_get_mark() - Inquire whether this mark is set on this entry.
@@ -1732,7 +1711,7 @@ EXPORT_SYMBOL(xa_get_mark);
* @index: Index of entry.
* @mark: Mark number.
*
- * Attempting to set a mark on a NULL entry does not succeed.
+ * Attempting to set a mark on a %NULL entry does not succeed.
*
* Context: Process context. Takes and releases the xa_lock.
*/
@@ -1829,6 +1808,8 @@ void *xa_find_after(struct xarray *xa, unsigned long *indexp,
entry = xas_find_marked(&xas, max, filter);
else
entry = xas_find(&xas, max);
+ if (xas.xa_node == XAS_BOUNDS)
+ break;
if (xas.xa_shift) {
if (xas.xa_index & ((1UL << xas.xa_shift) - 1))
continue;
@@ -1899,7 +1880,7 @@ static unsigned int xas_extract_marked(struct xa_state *xas, void **dst,
*
* The @filter may be an XArray mark value, in which case entries which are
* marked with that mark will be copied. It may also be %XA_PRESENT, in
- * which case all entries which are not NULL will be copied.
+ * which case all entries which are not %NULL will be copied.
*
* The entries returned may not represent a snapshot of the XArray at a
* moment in time. For example, if another thread stores to index 5, then