lib/stackdepot: put functions in logical order

Patch series "lib/stackdepot: fixes and clean-ups", v2.

A set of fixes, comments, and clean-ups I came up with while reading
the stack depot code.

This patch (of 18):

Put stack depot functions' declarations and definitions in a more logical
order:

1. Functions that save stack traces into stack depot.
2. Functions that fetch and print stack traces.
3. stack_depot_get_extra_bits that operates on stack depot handles
   and does not interact with the stack depot storage.

No functional changes.

Link: https://lkml.kernel.org/r/cover.1676063693.git.andreyknvl@google.com
Link: https://lkml.kernel.org/r/daca1319b665d826b94c596b992a8d8117846147.1676063693.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h
index 9ca7798..1296a6e 100644 (file)
--- a/include/linux/stackdepot.h
+++ b/include/linux/stackdepot.h
@@ -14,17 +14,13 @@
 #include <linux/gfp.h>
 
 typedef u32 depot_stack_handle_t;
+
 /*
  * Number of bits in the handle that stack depot doesn't use. Users may store
  * information in them.
  */
 #define STACK_DEPOT_EXTRA_BITS 5
 
-depot_stack_handle_t __stack_depot_save(unsigned long *entries,
-                                       unsigned int nr_entries,
-                                       unsigned int extra_bits,
-                                       gfp_t gfp_flags, bool can_alloc);
-
 /*
  * Every user of stack depot has to call stack_depot_init() during its own init
  * when it's decided that it will be calling stack_depot_save() later. This is
@@ -59,17 +55,22 @@ static inline void stack_depot_want_early_init(void) { }
 static inline int stack_depot_early_init(void) { return 0; }
 #endif
 
+depot_stack_handle_t __stack_depot_save(unsigned long *entries,
+                                       unsigned int nr_entries,
+                                       unsigned int extra_bits,
+                                       gfp_t gfp_flags, bool can_alloc);
+
 depot_stack_handle_t stack_depot_save(unsigned long *entries,
                                      unsigned int nr_entries, gfp_t gfp_flags);
 
 unsigned int stack_depot_fetch(depot_stack_handle_t handle,
                               unsigned long **entries);
 
-unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle);
+void stack_depot_print(depot_stack_handle_t stack);
 
 int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size,
                       int spaces);
 
-void stack_depot_print(depot_stack_handle_t stack);
+unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle);
 
 #endif

diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index 79e894c..4bfaf3b 100644 (file)
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -79,84 +79,6 @@ static int next_slab_inited;
 static size_t depot_offset;
 static DEFINE_RAW_SPINLOCK(depot_lock);
 
-unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle)
-{
-       union handle_parts parts = { .handle = handle };
-
-       return parts.extra;
-}
-EXPORT_SYMBOL(stack_depot_get_extra_bits);
-
-static bool init_stack_slab(void **prealloc)
-{
-       if (!*prealloc)
-               return false;
-       /*
-        * This smp_load_acquire() pairs with smp_store_release() to
-        * |next_slab_inited| below and in depot_alloc_stack().
-        */
-       if (smp_load_acquire(&next_slab_inited))
-               return true;
-       if (stack_slabs[depot_index] == NULL) {
-               stack_slabs[depot_index] = *prealloc;
-               *prealloc = NULL;
-       } else {
-               /* If this is the last depot slab, do not touch the next one. */
-               if (depot_index + 1 < STACK_ALLOC_MAX_SLABS) {
-                       stack_slabs[depot_index + 1] = *prealloc;
-                       *prealloc = NULL;
-               }
-               /*
-                * This smp_store_release pairs with smp_load_acquire() from
-                * |next_slab_inited| above and in stack_depot_save().
-                */
-               smp_store_release(&next_slab_inited, 1);
-       }
-       return true;
-}
-
-/* Allocation of a new stack in raw storage */
-static struct stack_record *
-depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc)
-{
-       struct stack_record *stack;
-       size_t required_size = struct_size(stack, entries, size);
-
-       required_size = ALIGN(required_size, 1 << STACK_ALLOC_ALIGN);
-
-       if (unlikely(depot_offset + required_size > STACK_ALLOC_SIZE)) {
-               if (unlikely(depot_index + 1 >= STACK_ALLOC_MAX_SLABS)) {
-                       WARN_ONCE(1, "Stack depot reached limit capacity");
-                       return NULL;
-               }
-               depot_index++;
-               depot_offset = 0;
-               /*
-                * smp_store_release() here pairs with smp_load_acquire() from
-                * |next_slab_inited| in stack_depot_save() and
-                * init_stack_slab().
-                */
-               if (depot_index + 1 < STACK_ALLOC_MAX_SLABS)
-                       smp_store_release(&next_slab_inited, 0);
-       }
-       init_stack_slab(prealloc);
-       if (stack_slabs[depot_index] == NULL)
-               return NULL;
-
-       stack = stack_slabs[depot_index] + depot_offset;
-
-       stack->hash = hash;
-       stack->size = size;
-       stack->handle.slabindex = depot_index;
-       stack->handle.offset = depot_offset >> STACK_ALLOC_ALIGN;
-       stack->handle.valid = 1;
-       stack->handle.extra = 0;
-       memcpy(stack->entries, entries, flex_array_size(stack, entries, size));
-       depot_offset += required_size;
-
-       return stack;
-}
-
 /* one hash table bucket entry per 16kB of memory */
 #define STACK_HASH_SCALE       14
 /* limited between 4k and 1M buckets */
@@ -270,6 +192,76 @@ int stack_depot_init(void)
 }
 EXPORT_SYMBOL_GPL(stack_depot_init);
 
+static bool init_stack_slab(void **prealloc)
+{
+       if (!*prealloc)
+               return false;
+       /*
+        * This smp_load_acquire() pairs with smp_store_release() to
+        * |next_slab_inited| below and in depot_alloc_stack().
+        */
+       if (smp_load_acquire(&next_slab_inited))
+               return true;
+       if (stack_slabs[depot_index] == NULL) {
+               stack_slabs[depot_index] = *prealloc;
+               *prealloc = NULL;
+       } else {
+               /* If this is the last depot slab, do not touch the next one. */
+               if (depot_index + 1 < STACK_ALLOC_MAX_SLABS) {
+                       stack_slabs[depot_index + 1] = *prealloc;
+                       *prealloc = NULL;
+               }
+               /*
+                * This smp_store_release pairs with smp_load_acquire() from
+                * |next_slab_inited| above and in stack_depot_save().
+                */
+               smp_store_release(&next_slab_inited, 1);
+       }
+       return true;
+}
+
+/* Allocation of a new stack in raw storage */
+static struct stack_record *
+depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc)
+{
+       struct stack_record *stack;
+       size_t required_size = struct_size(stack, entries, size);
+
+       required_size = ALIGN(required_size, 1 << STACK_ALLOC_ALIGN);
+
+       if (unlikely(depot_offset + required_size > STACK_ALLOC_SIZE)) {
+               if (unlikely(depot_index + 1 >= STACK_ALLOC_MAX_SLABS)) {
+                       WARN_ONCE(1, "Stack depot reached limit capacity");
+                       return NULL;
+               }
+               depot_index++;
+               depot_offset = 0;
+               /*
+                * smp_store_release() here pairs with smp_load_acquire() from
+                * |next_slab_inited| in stack_depot_save() and
+                * init_stack_slab().
+                */
+               if (depot_index + 1 < STACK_ALLOC_MAX_SLABS)
+                       smp_store_release(&next_slab_inited, 0);
+       }
+       init_stack_slab(prealloc);
+       if (stack_slabs[depot_index] == NULL)
+               return NULL;
+
+       stack = stack_slabs[depot_index] + depot_offset;
+
+       stack->hash = hash;
+       stack->size = size;
+       stack->handle.slabindex = depot_index;
+       stack->handle.offset = depot_offset >> STACK_ALLOC_ALIGN;
+       stack->handle.valid = 1;
+       stack->handle.extra = 0;
+       memcpy(stack->entries, entries, flex_array_size(stack, entries, size));
+       depot_offset += required_size;
+
+       return stack;
+}
+
 /* Calculate hash for a stack */
 static inline u32 hash_stack(unsigned long *entries, unsigned int size)
 {
@@ -310,85 +302,6 @@ static inline struct stack_record *find_stack(struct stack_record *bucket,
 }
 
 /**
- * stack_depot_snprint - print stack entries from a depot into a buffer
- *
- * @handle:    Stack depot handle which was returned from
- *             stack_depot_save().
- * @buf:       Pointer to the print buffer
- *
- * @size:      Size of the print buffer
- *
- * @spaces:    Number of leading spaces to print
- *
- * Return:     Number of bytes printed.
- */
-int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size,
-                      int spaces)
-{
-       unsigned long *entries;
-       unsigned int nr_entries;
-
-       nr_entries = stack_depot_fetch(handle, &entries);
-       return nr_entries ? stack_trace_snprint(buf, size, entries, nr_entries,
-                                               spaces) : 0;
-}
-EXPORT_SYMBOL_GPL(stack_depot_snprint);
-
-/**
- * stack_depot_print - print stack entries from a depot
- *
- * @stack:             Stack depot handle which was returned from
- *                     stack_depot_save().
- *
- */
-void stack_depot_print(depot_stack_handle_t stack)
-{
-       unsigned long *entries;
-       unsigned int nr_entries;
-
-       nr_entries = stack_depot_fetch(stack, &entries);
-       if (nr_entries > 0)
-               stack_trace_print(entries, nr_entries, 0);
-}
-EXPORT_SYMBOL_GPL(stack_depot_print);
-
-/**
- * stack_depot_fetch - Fetch stack entries from a depot
- *
- * @handle:            Stack depot handle which was returned from
- *                     stack_depot_save().
- * @entries:           Pointer to store the entries address
- *
- * Return: The number of trace entries for this depot.
- */
-unsigned int stack_depot_fetch(depot_stack_handle_t handle,
-                              unsigned long **entries)
-{
-       union handle_parts parts = { .handle = handle };
-       void *slab;
-       size_t offset = parts.offset << STACK_ALLOC_ALIGN;
-       struct stack_record *stack;
-
-       *entries = NULL;
-       if (!handle)
-               return 0;
-
-       if (parts.slabindex > depot_index) {
-               WARN(1, "slab index %d out of bounds (%d) for stack id %08x\n",
-                       parts.slabindex, depot_index, handle);
-               return 0;
-       }
-       slab = stack_slabs[parts.slabindex];
-       if (!slab)
-               return 0;
-       stack = slab + offset;
-
-       *entries = stack->entries;
-       return stack->size;
-}
-EXPORT_SYMBOL_GPL(stack_depot_fetch);
-
-/**
  * __stack_depot_save - Save a stack trace from an array
  *
  * @entries:           Pointer to storage array
@@ -533,3 +446,90 @@ depot_stack_handle_t stack_depot_save(unsigned long *entries,
        return __stack_depot_save(entries, nr_entries, 0, alloc_flags, true);
 }
 EXPORT_SYMBOL_GPL(stack_depot_save);
+
+/**
+ * stack_depot_fetch - Fetch stack entries from a depot
+ *
+ * @handle:            Stack depot handle which was returned from
+ *                     stack_depot_save().
+ * @entries:           Pointer to store the entries address
+ *
+ * Return: The number of trace entries for this depot.
+ */
+unsigned int stack_depot_fetch(depot_stack_handle_t handle,
+                              unsigned long **entries)
+{
+       union handle_parts parts = { .handle = handle };
+       void *slab;
+       size_t offset = parts.offset << STACK_ALLOC_ALIGN;
+       struct stack_record *stack;
+
+       *entries = NULL;
+       if (!handle)
+               return 0;
+
+       if (parts.slabindex > depot_index) {
+               WARN(1, "slab index %d out of bounds (%d) for stack id %08x\n",
+                       parts.slabindex, depot_index, handle);
+               return 0;
+       }
+       slab = stack_slabs[parts.slabindex];
+       if (!slab)
+               return 0;
+       stack = slab + offset;
+
+       *entries = stack->entries;
+       return stack->size;
+}
+EXPORT_SYMBOL_GPL(stack_depot_fetch);
+
+/**
+ * stack_depot_print - print stack entries from a depot
+ *
+ * @stack:             Stack depot handle which was returned from
+ *                     stack_depot_save().
+ *
+ */
+void stack_depot_print(depot_stack_handle_t stack)
+{
+       unsigned long *entries;
+       unsigned int nr_entries;
+
+       nr_entries = stack_depot_fetch(stack, &entries);
+       if (nr_entries > 0)
+               stack_trace_print(entries, nr_entries, 0);
+}
+EXPORT_SYMBOL_GPL(stack_depot_print);
+
+/**
+ * stack_depot_snprint - print stack entries from a depot into a buffer
+ *
+ * @handle:    Stack depot handle which was returned from
+ *             stack_depot_save().
+ * @buf:       Pointer to the print buffer
+ *
+ * @size:      Size of the print buffer
+ *
+ * @spaces:    Number of leading spaces to print
+ *
+ * Return:     Number of bytes printed.
+ */
+int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size,
+                      int spaces)
+{
+       unsigned long *entries;
+       unsigned int nr_entries;
+
+       nr_entries = stack_depot_fetch(handle, &entries);
+       return nr_entries ? stack_trace_snprint(buf, size, entries, nr_entries,
+                                               spaces) : 0;
+}
+EXPORT_SYMBOL_GPL(stack_depot_snprint);
+
+unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle)
+{
+       union handle_parts parts = { .handle = handle };
+
+       return parts.extra;
+}
+EXPORT_SYMBOL(stack_depot_get_extra_bits);