Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module updates from Rusty Russell:
 "Main excitement here is Peter Zijlstra's lockless rbtree optimization
  to speed module address lookup.  He found some abusers of the module
  lock doing that too.

  A little bit of parameter work here too; including Dan Streetman's
  breaking up the big param mutex so writing a parameter can load
  another module (yeah, really).  Unfortunately that broke the usual
  suspects, !CONFIG_MODULES and !CONFIG_SYSFS, so those fixes were
  appended too"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (26 commits)
  modules: only use mod->param_lock if CONFIG_MODULES
  param: fix module param locks when !CONFIG_SYSFS.
  rcu: merge fix for Convert ACCESS_ONCE() to READ_ONCE() and WRITE_ONCE()
  module: add per-module param_lock
  module: make perm const
  params: suppress unused variable error, warn once just in case code changes.
  modules: clarify CONFIG_MODULE_COMPRESS help, suggest 'N'.
  kernel/module.c: avoid ifdefs for sig_enforce declaration
  kernel/workqueue.c: remove ifdefs over wq_power_efficient
  kernel/params.c: export param_ops_bool_enable_only
  kernel/params.c: generalize bool_enable_only
  kernel/module.c: use generic module param operaters for sig_enforce
  kernel/params: constify struct kernel_param_ops uses
  sysfs: tightened sysfs permission checks
  module: Rework module_addr_{min,max}
  module: Use __module_address() for module_address_lookup()
  module: Make the mod_tree stuff conditional on PERF_EVENTS || TRACING
  module: Optimize __module_address() using a latched RB-tree
  rbtree: Implement generic latch_tree
  seqlock: Introduce raw_read_seqcount_latch()
  ...

1 files changed, 41 insertions, 5 deletions

diff --git a/include/linux/module.h b/include/linux/module.h
index 7ffe0851d244..d67b1932cc59 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -17,6 +17,7 @@
 #include <linux/moduleparam.h>
 #include <linux/jump_label.h>
 #include <linux/export.h>
+#include <linux/rbtree_latch.h>
 
 #include <linux/percpu.h>
 #include <asm/module.h>
@@ -210,6 +211,13 @@ enum module_state {
         MODULE_STATE_UNFORMED,  /* Still setting it up. */
 };
 
+struct module;
+
+struct mod_tree_node {
+        struct module *mod;
+        struct latch_tree_node node;
+};
+
 struct module {
         enum module_state state;
 
@@ -232,6 +240,9 @@ struct module {
         unsigned int num_syms;
 
         /* Kernel parameters. */
+#ifdef CONFIG_SYSFS
+        struct mutex param_lock;
+#endif
         struct kernel_param *kp;
         unsigned int num_kp;
 
@@ -271,8 +282,15 @@ struct module {
         /* Startup function. */
         int (*init)(void);
 
-        /* If this is non-NULL, vfree after init() returns */
-        void *module_init;
+        /*
+         * If this is non-NULL, vfree() after init() returns.
+         *
+         * Cacheline align here, such that:
+         *   module_init, module_core, init_size, core_size,
+         *   init_text_size, core_text_size and mtn_core::{mod,node[0]}
+         * are on the same cacheline.
+         */
+        void *module_init       ____cacheline_aligned;
 
         /* Here is the actual code + data, vfree'd on unload. */
         void *module_core;
@@ -283,6 +301,16 @@ struct module {
         /* The size of the executable code in each section.  */
         unsigned int init_text_size, core_text_size;
 
+#ifdef CONFIG_MODULES_TREE_LOOKUP
+        /*
+         * We want mtn_core::{mod,node[0]} to be in the same cacheline as the
+         * above entries such that a regular lookup will only touch one
+         * cacheline.
+         */
+        struct mod_tree_node    mtn_core;
+        struct mod_tree_node    mtn_init;
+#endif
+
         /* Size of RO sections of the module (text+rodata) */
         unsigned int init_ro_size, core_ro_size;
 
@@ -369,7 +397,7 @@ struct module {
         ctor_fn_t *ctors;
         unsigned int num_ctors;
 #endif
-};
+} ____cacheline_aligned;
 #ifndef MODULE_ARCH_INIT
 #define MODULE_ARCH_INIT {}
 #endif
@@ -423,14 +451,22 @@ struct symsearch {
         bool unused;
 };
 
-/* Search for an exported symbol by name. */
+/*
+ * Search for an exported symbol by name.
+ *
+ * Must be called with module_mutex held or preemption disabled.
+ */
 const struct kernel_symbol *find_symbol(const char *name,
                                         struct module **owner,
                                         const unsigned long **crc,
                                         bool gplok,
                                         bool warn);
 
-/* Walk the exported symbol table */
+/*
+ * Walk the exported symbol table
+ *
+ * Must be called with module_mutex held or preemption disabled.
+ */
 bool each_symbol_section(bool (*fn)(const struct symsearch *arr,
                                     struct module *owner,
                                     void *data), void *data);