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authorMatthew Wilcox <willy@infradead.org>2018-07-04 10:50:12 -0400
committerMatthew Wilcox <willy@infradead.org>2018-10-21 10:46:32 -0400
commit371c752dc66948714ee3b66c3306f3ff1ff71d2e (patch)
treea9707d94787474e20b4efcd9bc81d5e6e1328a66 /include/linux/xarray.h
parent3d5bd6e1a04ae779bc5e0de9ba2e92aa55c40fe8 (diff)
downloadlinux-stericsson-371c752dc66948714ee3b66c3306f3ff1ff71d2e.tar.gz
xarray: Track free entries in an XArray
Add the optional ability to track which entries in an XArray are free and provide xa_alloc() to replace most of the functionality of the IDR. Signed-off-by: Matthew Wilcox <willy@infradead.org>
Diffstat (limited to 'include/linux/xarray.h')
-rw-r--r--include/linux/xarray.h101
1 files changed, 101 insertions, 0 deletions
diff --git a/include/linux/xarray.h b/include/linux/xarray.h
index bed63d3cfea8..e0b57af52e9b 100644
--- a/include/linux/xarray.h
+++ b/include/linux/xarray.h
@@ -205,6 +205,7 @@ typedef unsigned __bitwise xa_mark_t;
#define XA_MARK_2 ((__force xa_mark_t)2U)
#define XA_PRESENT ((__force xa_mark_t)8U)
#define XA_MARK_MAX XA_MARK_2
+#define XA_FREE_MARK XA_MARK_0
enum xa_lock_type {
XA_LOCK_IRQ = 1,
@@ -217,9 +218,12 @@ enum xa_lock_type {
*/
#define XA_FLAGS_LOCK_IRQ ((__force gfp_t)XA_LOCK_IRQ)
#define XA_FLAGS_LOCK_BH ((__force gfp_t)XA_LOCK_BH)
+#define XA_FLAGS_TRACK_FREE ((__force gfp_t)4U)
#define XA_FLAGS_MARK(mark) ((__force gfp_t)((1U << __GFP_BITS_SHIFT) << \
(__force unsigned)(mark)))
+#define XA_FLAGS_ALLOC (XA_FLAGS_TRACK_FREE | XA_FLAGS_MARK(XA_FREE_MARK))
+
/**
* struct xarray - The anchor of the XArray.
* @xa_lock: Lock that protects the contents of the XArray.
@@ -273,6 +277,15 @@ struct xarray {
*/
#define DEFINE_XARRAY(name) DEFINE_XARRAY_FLAGS(name, 0)
+/**
+ * DEFINE_XARRAY_ALLOC() - Define an XArray which can allocate IDs.
+ * @name: A string that names your XArray.
+ *
+ * This is intended for file scope definitions of allocating XArrays.
+ * See also DEFINE_XARRAY().
+ */
+#define DEFINE_XARRAY_ALLOC(name) DEFINE_XARRAY_FLAGS(name, XA_FLAGS_ALLOC)
+
void xa_init_flags(struct xarray *, gfp_t flags);
void *xa_load(struct xarray *, unsigned long index);
void *xa_store(struct xarray *, unsigned long index, void *entry, gfp_t);
@@ -439,6 +452,7 @@ 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_alloc(struct xarray *, u32 *id, u32 max, void *entry, 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);
@@ -518,6 +532,93 @@ static inline void *xa_erase_irq(struct xarray *xa, unsigned long index)
return entry;
}
+/**
+ * xa_alloc() - Find somewhere to store this entry in the XArray.
+ * @xa: XArray.
+ * @id: Pointer to ID.
+ * @max: Maximum ID to allocate (inclusive).
+ * @entry: New entry.
+ * @gfp: Memory allocation flags.
+ *
+ * Allocates an unused ID in the range specified by @id and @max.
+ * Updates the @id pointer with the index, then stores the entry at that
+ * index. A concurrent lookup will not see an uninitialised @id.
+ *
+ * Context: Process context. Takes and releases the xa_lock. May sleep if
+ * the @gfp flags permit.
+ * Return: 0 on success, -ENOMEM if memory allocation fails or -ENOSPC if
+ * there is no more space in the XArray.
+ */
+static inline int xa_alloc(struct xarray *xa, u32 *id, u32 max, void *entry,
+ gfp_t gfp)
+{
+ int err;
+
+ xa_lock(xa);
+ err = __xa_alloc(xa, id, max, entry, gfp);
+ xa_unlock(xa);
+
+ return err;
+}
+
+/**
+ * xa_alloc_bh() - Find somewhere to store this entry in the XArray.
+ * @xa: XArray.
+ * @id: Pointer to ID.
+ * @max: Maximum ID to allocate (inclusive).
+ * @entry: New entry.
+ * @gfp: Memory allocation flags.
+ *
+ * Allocates an unused ID in the range specified by @id and @max.
+ * Updates the @id pointer with the index, then stores the entry at that
+ * index. A concurrent lookup will not see an uninitialised @id.
+ *
+ * Context: Process context. Takes and releases the xa_lock while
+ * disabling softirqs. May sleep if the @gfp flags permit.
+ * Return: 0 on success, -ENOMEM if memory allocation fails or -ENOSPC if
+ * there is no more space in the XArray.
+ */
+static inline int xa_alloc_bh(struct xarray *xa, u32 *id, u32 max, void *entry,
+ gfp_t gfp)
+{
+ int err;
+
+ xa_lock_bh(xa);
+ err = __xa_alloc(xa, id, max, entry, gfp);
+ xa_unlock_bh(xa);
+
+ return err;
+}
+
+/**
+ * xa_alloc_irq() - Find somewhere to store this entry in the XArray.
+ * @xa: XArray.
+ * @id: Pointer to ID.
+ * @max: Maximum ID to allocate (inclusive).
+ * @entry: New entry.
+ * @gfp: Memory allocation flags.
+ *
+ * Allocates an unused ID in the range specified by @id and @max.
+ * Updates the @id pointer with the index, then stores the entry at that
+ * index. A concurrent lookup will not see an uninitialised @id.
+ *
+ * Context: Process context. Takes and releases the xa_lock while
+ * disabling interrupts. May sleep if the @gfp flags permit.
+ * Return: 0 on success, -ENOMEM if memory allocation fails or -ENOSPC if
+ * there is no more space in the XArray.
+ */
+static inline int xa_alloc_irq(struct xarray *xa, u32 *id, u32 max, void *entry,
+ gfp_t gfp)
+{
+ int err;
+
+ xa_lock_irq(xa);
+ err = __xa_alloc(xa, id, max, entry, gfp);
+ xa_unlock_irq(xa);
+
+ return err;
+}
+
/* Everything below here is the Advanced API. Proceed with caution. */
/*