module: refactor load_module

I'd start from the trivial stuff. There's a fair amount of straight-line
code that just makes the function hard to read just because you have to
page up and down so far. Some of it is trivial to just create a helper
function for.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 69 insertions, 61 deletions

diff --git a/kernel/module.c b/kernel/module.c
index 404e722930fc..12905ed44393 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2107,6 +2107,71 @@ static inline void kmemleak_load_module(struct module *mod, Elf_Ehdr *hdr,
 }
 #endif
 
+static void find_module_sections(struct module *mod, Elf_Ehdr *hdr,
+                                 Elf_Shdr *sechdrs, const char *secstrings)
+{
+        mod->kp = section_objs(hdr, sechdrs, secstrings, "__param",
+                               sizeof(*mod->kp), &mod->num_kp);
+        mod->syms = section_objs(hdr, sechdrs, secstrings, "__ksymtab",
+                                 sizeof(*mod->syms), &mod->num_syms);
+        mod->crcs = section_addr(hdr, sechdrs, secstrings, "__kcrctab");
+        mod->gpl_syms = section_objs(hdr, sechdrs, secstrings, "__ksymtab_gpl",
+                                     sizeof(*mod->gpl_syms),
+                                     &mod->num_gpl_syms);
+        mod->gpl_crcs = section_addr(hdr, sechdrs, secstrings, "__kcrctab_gpl");
+        mod->gpl_future_syms = section_objs(hdr, sechdrs, secstrings,
+                                            "__ksymtab_gpl_future",
+                                            sizeof(*mod->gpl_future_syms),
+                                            &mod->num_gpl_future_syms);
+        mod->gpl_future_crcs = section_addr(hdr, sechdrs, secstrings,
+                                            "__kcrctab_gpl_future");
+
+#ifdef CONFIG_UNUSED_SYMBOLS
+        mod->unused_syms = section_objs(hdr, sechdrs, secstrings,
+                                        "__ksymtab_unused",
+                                        sizeof(*mod->unused_syms),
+                                        &mod->num_unused_syms);
+        mod->unused_crcs = section_addr(hdr, sechdrs, secstrings,
+                                        "__kcrctab_unused");
+        mod->unused_gpl_syms = section_objs(hdr, sechdrs, secstrings,
+                                            "__ksymtab_unused_gpl",
+                                            sizeof(*mod->unused_gpl_syms),
+                                            &mod->num_unused_gpl_syms);
+        mod->unused_gpl_crcs = section_addr(hdr, sechdrs, secstrings,
+                                            "__kcrctab_unused_gpl");
+#endif
+#ifdef CONFIG_CONSTRUCTORS
+        mod->ctors = section_objs(hdr, sechdrs, secstrings, ".ctors",
+                                  sizeof(*mod->ctors), &mod->num_ctors);
+#endif
+
+#ifdef CONFIG_TRACEPOINTS
+        mod->tracepoints = section_objs(hdr, sechdrs, secstrings,
+                                        "__tracepoints",
+                                        sizeof(*mod->tracepoints),
+                                        &mod->num_tracepoints);
+#endif
+#ifdef CONFIG_EVENT_TRACING
+        mod->trace_events = section_objs(hdr, sechdrs, secstrings,
+                                         "_ftrace_events",
+                                         sizeof(*mod->trace_events),
+                                         &mod->num_trace_events);
+        /*
+         * This section contains pointers to allocated objects in the trace
+         * code and not scanning it leads to false positives.
+         */
+        kmemleak_scan_area(mod->trace_events, sizeof(*mod->trace_events) *
+                           mod->num_trace_events, GFP_KERNEL);
+#endif
+#ifdef CONFIG_FTRACE_MCOUNT_RECORD
+        /* sechdrs[0].sh_size is always zero */
+        mod->ftrace_callsites = section_objs(hdr, sechdrs, secstrings,
+                                             "__mcount_loc",
+                                             sizeof(*mod->ftrace_callsites),
+                                             &mod->num_ftrace_callsites);
+#endif
+}
+
 /* Allocate and load the module: note that size of section 0 is always
    zero, and we rely on this for optional sections. */
 static noinline struct module *load_module(void __user *umod,
@@ -2147,7 +2212,7 @@ static noinline struct module *load_module(void __user *umod,
         }
 
         /* Sanity checks against insmoding binaries or wrong arch,
-           weird elf version */
+           weird elf version */
         if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0
             || hdr->e_type != ET_REL
             || !elf_check_arch(hdr)
@@ -2326,7 +2391,8 @@ static noinline struct module *load_module(void __user *umod,
                                sechdrs[i].sh_size);
                 /* Update sh_addr to point to copy in image. */
                 sechdrs[i].sh_addr = (unsigned long)dest;
-                DEBUGP("\t0x%lx %s\n", sechdrs[i].sh_addr, secstrings + sechdrs[i].sh_name);
+                DEBUGP("\t0x%lx %s\n",
+                       sechdrs[i].sh_addr, secstrings + sechdrs[i].sh_name);
         }
         /* Module has been moved. */
         mod = (void *)sechdrs[modindex].sh_addr;
@@ -2368,66 +2434,8 @@ static noinline struct module *load_module(void __user *umod,
 
         /* Now we've got everything in the final locations, we can
          * find optional sections. */
-        mod->kp = section_objs(hdr, sechdrs, secstrings, "__param",
-                               sizeof(*mod->kp), &mod->num_kp);
-        mod->syms = section_objs(hdr, sechdrs, secstrings, "__ksymtab",
-                                 sizeof(*mod->syms), &mod->num_syms);
-        mod->crcs = section_addr(hdr, sechdrs, secstrings, "__kcrctab");
-        mod->gpl_syms = section_objs(hdr, sechdrs, secstrings, "__ksymtab_gpl",
-                                     sizeof(*mod->gpl_syms),
-                                     &mod->num_gpl_syms);
-        mod->gpl_crcs = section_addr(hdr, sechdrs, secstrings, "__kcrctab_gpl");
-        mod->gpl_future_syms = section_objs(hdr, sechdrs, secstrings,
-                                            "__ksymtab_gpl_future",
-                                            sizeof(*mod->gpl_future_syms),
-                                            &mod->num_gpl_future_syms);
-        mod->gpl_future_crcs = section_addr(hdr, sechdrs, secstrings,
-                                            "__kcrctab_gpl_future");
+        find_module_sections(mod, hdr, sechdrs, secstrings);
 
-#ifdef CONFIG_UNUSED_SYMBOLS
-        mod->unused_syms = section_objs(hdr, sechdrs, secstrings,
-                                        "__ksymtab_unused",
-                                        sizeof(*mod->unused_syms),
-                                        &mod->num_unused_syms);
-        mod->unused_crcs = section_addr(hdr, sechdrs, secstrings,
-                                        "__kcrctab_unused");
-        mod->unused_gpl_syms = section_objs(hdr, sechdrs, secstrings,
-                                            "__ksymtab_unused_gpl",
-                                            sizeof(*mod->unused_gpl_syms),
-                                            &mod->num_unused_gpl_syms);
-        mod->unused_gpl_crcs = section_addr(hdr, sechdrs, secstrings,
-                                            "__kcrctab_unused_gpl");
-#endif
-#ifdef CONFIG_CONSTRUCTORS
-        mod->ctors = section_objs(hdr, sechdrs, secstrings, ".ctors",
-                                  sizeof(*mod->ctors), &mod->num_ctors);
-#endif
-
-#ifdef CONFIG_TRACEPOINTS
-        mod->tracepoints = section_objs(hdr, sechdrs, secstrings,
-                                        "__tracepoints",
-                                        sizeof(*mod->tracepoints),
-                                        &mod->num_tracepoints);
-#endif
-#ifdef CONFIG_EVENT_TRACING
-        mod->trace_events = section_objs(hdr, sechdrs, secstrings,
-                                         "_ftrace_events",
-                                         sizeof(*mod->trace_events),
-                                         &mod->num_trace_events);
-        /*
-         * This section contains pointers to allocated objects in the trace
-         * code and not scanning it leads to false positives.
-         */
-        kmemleak_scan_area(mod->trace_events, sizeof(*mod->trace_events) *
-                           mod->num_trace_events, GFP_KERNEL);
-#endif
-#ifdef CONFIG_FTRACE_MCOUNT_RECORD
-        /* sechdrs[0].sh_size is always zero */
-        mod->ftrace_callsites = section_objs(hdr, sechdrs, secstrings,
-                                             "__mcount_loc",
-                                             sizeof(*mod->ftrace_callsites),
-                                             &mod->num_ftrace_callsites);
-#endif
 #ifdef CONFIG_MODVERSIONS
         if ((mod->num_syms && !mod->crcs)
             || (mod->num_gpl_syms && !mod->gpl_crcs)