Merge tag 'trace-v6.9-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux...

[sfrench/cifs-2.6.git] / include / linux / stackdepot.h

diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h
index adcbb8f23600072310e23f6bb5a395683c196fc3..3c6caa5abc7c4262b8d62f9ef46d3fa273e7fb1e 100644 (file)
--- a/include/linux/stackdepot.h
+++ b/include/linux/stackdepot.h
@@ -30,6 +30,53 @@ typedef u32 depot_stack_handle_t;
  */
 #define STACK_DEPOT_EXTRA_BITS 5
 
+#define DEPOT_HANDLE_BITS (sizeof(depot_stack_handle_t) * 8)
+
+#define DEPOT_POOL_ORDER 2 /* Pool size order, 4 pages */
+#define DEPOT_POOL_SIZE (1LL << (PAGE_SHIFT + DEPOT_POOL_ORDER))
+#define DEPOT_STACK_ALIGN 4
+#define DEPOT_OFFSET_BITS (DEPOT_POOL_ORDER + PAGE_SHIFT - DEPOT_STACK_ALIGN)
+#define DEPOT_POOL_INDEX_BITS (DEPOT_HANDLE_BITS - DEPOT_OFFSET_BITS - \
+                              STACK_DEPOT_EXTRA_BITS)
+
+#ifdef CONFIG_STACKDEPOT
+/* Compact structure that stores a reference to a stack. */
+union handle_parts {
+       depot_stack_handle_t handle;
+       struct {
+               /* pool_index is offset by 1 */
+               u32 pool_index  : DEPOT_POOL_INDEX_BITS;
+               u32 offset      : DEPOT_OFFSET_BITS;
+               u32 extra       : STACK_DEPOT_EXTRA_BITS;
+       };
+};
+
+struct stack_record {
+       struct list_head hash_list;     /* Links in the hash table */
+       u32 hash;                       /* Hash in hash table */
+       u32 size;                       /* Number of stored frames */
+       union handle_parts handle;      /* Constant after initialization */
+       refcount_t count;
+       union {
+               unsigned long entries[CONFIG_STACKDEPOT_MAX_FRAMES];    /* Frames */
+               struct {
+                       /*
+                        * An important invariant of the implementation is to
+                        * only place a stack record onto the freelist iff its
+                        * refcount is zero. Because stack records with a zero
+                        * refcount are never considered as valid, it is safe to
+                        * union @entries and freelist management state below.
+                        * Conversely, as soon as an entry is off the freelist
+                        * and its refcount becomes non-zero, the below must not
+                        * be accessed until being placed back on the freelist.
+                        */
+                       struct list_head free_list;     /* Links in the freelist */
+                       unsigned long rcu_state;        /* RCU cookie */
+               };
+       };
+};
+#endif
+
 typedef u32 depot_flags_t;
 
 /*
@@ -131,6 +178,17 @@ depot_stack_handle_t stack_depot_save_flags(unsigned long *entries,
 depot_stack_handle_t stack_depot_save(unsigned long *entries,
                                      unsigned int nr_entries, gfp_t gfp_flags);
 
+/**
+ * __stack_depot_get_stack_record - Get a pointer to a stack_record struct
+ *
+ * @handle: Stack depot handle
+ *
+ * This function is only for internal purposes.
+ *
+ * Return: Returns a pointer to a stack_record struct
+ */
+struct stack_record *__stack_depot_get_stack_record(depot_stack_handle_t handle);
+
 /**
  * stack_depot_fetch - Fetch a stack trace from stack depot
  *