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authorMatthew Wilcox <willy@infradead.org>2019-01-02 21:57:03 +0300
committerMatthew Wilcox <willy@infradead.org>2019-01-07 06:12:58 +0300
commitb0606fed6eece16a421034eca0bbea9a08b90e91 (patch)
treef705b58760a60fce2d6f03a934a5038154505c1b /include/linux/xarray.h
parent76b4e52995654af260f14558e0e07b5b039ae202 (diff)
downloadlinux-b0606fed6eece16a421034eca0bbea9a08b90e91.tar.xz
XArray: Honour reserved entries in xa_insert
xa_insert() should treat reserved entries as occupied, not as available. Also, it should treat requests to insert a NULL pointer as a request to reserve the slot. Add xa_insert_bh() and xa_insert_irq() for completeness. Signed-off-by: Matthew Wilcox <willy@infradead.org>
Diffstat (limited to 'include/linux/xarray.h')
-rw-r--r--include/linux/xarray.h110
1 files changed, 71 insertions, 39 deletions
diff --git a/include/linux/xarray.h b/include/linux/xarray.h
index 435c25b29079..12244aa98a69 100644
--- a/include/linux/xarray.h
+++ b/include/linux/xarray.h
@@ -463,40 +463,13 @@ void *__xa_erase(struct xarray *, unsigned long index);
void *__xa_store(struct xarray *, unsigned long index, void *entry, gfp_t);
void *__xa_cmpxchg(struct xarray *, unsigned long index, void *old,
void *entry, gfp_t);
+int __xa_insert(struct xarray *, unsigned long index, void *entry, gfp_t);
int __xa_alloc(struct xarray *, u32 *id, u32 max, void *entry, gfp_t);
int __xa_reserve(struct xarray *, unsigned long index, gfp_t);
void __xa_set_mark(struct xarray *, unsigned long index, xa_mark_t);
void __xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t);
/**
- * __xa_insert() - Store this entry in the XArray unless another entry is
- * already present.
- * @xa: XArray.
- * @index: Index into array.
- * @entry: New entry.
- * @gfp: Memory allocation flags.
- *
- * If you would rather see the existing entry in the array, use __xa_cmpxchg().
- * This function is for users who don't care what the entry is, only that
- * one is present.
- *
- * Context: Any context. Expects xa_lock to be held on entry. May
- * release and reacquire xa_lock if the @gfp flags permit.
- * Return: 0 if the store succeeded. -EEXIST if another entry was present.
- * -ENOMEM if memory could not be allocated.
- */
-static inline int __xa_insert(struct xarray *xa, unsigned long index,
- void *entry, gfp_t gfp)
-{
- void *curr = __xa_cmpxchg(xa, index, NULL, entry, gfp);
- if (!curr)
- return 0;
- if (xa_is_err(curr))
- return xa_err(curr);
- return -EEXIST;
-}
-
-/**
* xa_store_bh() - Store this entry in the XArray.
* @xa: XArray.
* @index: Index into array.
@@ -685,24 +658,83 @@ static inline void *xa_cmpxchg_irq(struct xarray *xa, unsigned long index,
* @entry: New entry.
* @gfp: Memory allocation flags.
*
- * If you would rather see the existing entry in the array, use xa_cmpxchg().
- * This function is for users who don't care what the entry is, only that
- * one is present.
+ * Inserting a NULL entry will store a reserved entry (like xa_reserve())
+ * if no entry is present. Inserting will fail if a reserved entry is
+ * present, even though loading from this index will return NULL.
*
- * Context: Process context. Takes and releases the xa_lock.
- * May sleep if the @gfp flags permit.
+ * Context: Any context. Takes and releases the xa_lock. May sleep if
+ * the @gfp flags permit.
* Return: 0 if the store succeeded. -EEXIST if another entry was present.
* -ENOMEM if memory could not be allocated.
*/
static inline int xa_insert(struct xarray *xa, unsigned long index,
void *entry, gfp_t gfp)
{
- void *curr = xa_cmpxchg(xa, index, NULL, entry, gfp);
- if (!curr)
- return 0;
- if (xa_is_err(curr))
- return xa_err(curr);
- return -EEXIST;
+ int err;
+
+ xa_lock(xa);
+ err = __xa_insert(xa, index, entry, gfp);
+ xa_unlock(xa);
+
+ return err;
+}
+
+/**
+ * xa_insert_bh() - Store this entry in the XArray unless another entry is
+ * already present.
+ * @xa: XArray.
+ * @index: Index into array.
+ * @entry: New entry.
+ * @gfp: Memory allocation flags.
+ *
+ * Inserting a NULL entry will store a reserved entry (like xa_reserve())
+ * if no entry is present. Inserting will fail if a reserved entry is
+ * present, even though loading from this index will return NULL.
+ *
+ * Context: Any context. Takes and releases the xa_lock while
+ * disabling softirqs. May sleep if the @gfp flags permit.
+ * Return: 0 if the store succeeded. -EEXIST if another entry was present.
+ * -ENOMEM if memory could not be allocated.
+ */
+static inline int xa_insert_bh(struct xarray *xa, unsigned long index,
+ void *entry, gfp_t gfp)
+{
+ int err;
+
+ xa_lock_bh(xa);
+ err = __xa_insert(xa, index, entry, gfp);
+ xa_unlock_bh(xa);
+
+ return err;
+}
+
+/**
+ * xa_insert_irq() - Store this entry in the XArray unless another entry is
+ * already present.
+ * @xa: XArray.
+ * @index: Index into array.
+ * @entry: New entry.
+ * @gfp: Memory allocation flags.
+ *
+ * Inserting a NULL entry will store a reserved entry (like xa_reserve())
+ * if no entry is present. Inserting will fail if a reserved entry is
+ * present, even though loading from this index will return NULL.
+ *
+ * Context: Process context. Takes and releases the xa_lock while
+ * disabling interrupts. May sleep if the @gfp flags permit.
+ * Return: 0 if the store succeeded. -EEXIST if another entry was present.
+ * -ENOMEM if memory could not be allocated.
+ */
+static inline int xa_insert_irq(struct xarray *xa, unsigned long index,
+ void *entry, gfp_t gfp)
+{
+ int err;
+
+ xa_lock_irq(xa);
+ err = __xa_insert(xa, index, entry, gfp);
+ xa_unlock_irq(xa);
+
+ return err;
}
/**