* (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)
{
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.
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));
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.
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);
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));
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.
* 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,
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))
* @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.
*/
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.
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.
* @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.
*/
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;
*
* 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
projects / linux-2.6-block.git / blobdiff