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)