[src/trunk]: src/sys/kern kobj(9): Rephrase kobj_load and kobj_affix positively.

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/1d0652f5ac74
branches:  trunk
changeset: 371874:1d0652f5ac74
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sat Oct 15 15:28:23 2022 +0000

description:
kobj(9): Rephrase kobj_load and kobj_affix positively.

Write error cases as branches, normal cases as straight-line code.

Side effect: One fewer call to kobj_jettison in case of error in
kobj_affix, but it already calls kobj_jettison once in the error case
via kobj_unload, which does kobj_jettison itself, and kobj_jettison
is idempotent.

No functional change intended.

diffstat:

 sys/kern/subr_kobj.c |  76 ++++++++++++++++++++++++++++++---------------------
 1 files changed, 44 insertions(+), 32 deletions(-)

diffs (141 lines):

diff -r d397c4dcb432 -r 1d0652f5ac74 sys/kern/subr_kobj.c
--- a/sys/kern/subr_kobj.c      Sat Oct 15 15:27:20 2022 +0000
+++ b/sys/kern/subr_kobj.c      Sat Oct 15 15:28:23 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: subr_kobj.c,v 1.72 2022/10/15 15:27:20 riastradh Exp $ */
+/*     $NetBSD: subr_kobj.c,v 1.73 2022/10/15 15:28:23 riastradh Exp $ */
 
 /*
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -63,7 +63,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: subr_kobj.c,v 1.72 2022/10/15 15:27:20 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_kobj.c,v 1.73 2022/10/15 15:28:23 riastradh Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_modular.h"
@@ -610,10 +610,13 @@
         * symbols will be done by kobj_affix().
         */
        error = kobj_checksyms(ko, false);
-       if (error == 0) {
-               error = kobj_relocate(ko, true);
-       }
- out:
+       if (error)
+               goto out;
+
+       error = kobj_relocate(ko, true);
+       if (error)
+               goto out;
+out:
        if (hdr != NULL) {
                kobj_free(ko, hdr, sizeof(*hdr));
        }
@@ -731,21 +734,22 @@
 
        /* Cache addresses of undefined symbols. */
        error = kobj_checksyms(ko, true);
+       if (error)
+               goto out;
 
        /* Now do global relocations. */
-       if (error == 0)
-               error = kobj_relocate(ko, false);
+       error = kobj_relocate(ko, false);
+       if (error)
+               goto out;
 
        /*
         * Now that we know the name, register the symbol table.
         * Do after global relocations because ksyms will pack
         * the table.
         */
-       if (error == 0) {
-               ksyms_modload(ko->ko_name, ko->ko_symtab, ko->ko_symcnt *
-                   sizeof(Elf_Sym), ko->ko_strtab, ko->ko_strtabsz);
-               ko->ko_ksyms = true;
-       }
+       ksyms_modload(ko->ko_name, ko->ko_symtab,
+           ko->ko_symcnt * sizeof(Elf_Sym), ko->ko_strtab, ko->ko_strtabsz);
+       ko->ko_ksyms = true;
 
        /* Jettison unneeded memory post-link. */
        kobj_jettison(ko);
@@ -755,47 +759,55 @@
         *
         * Most architectures use this opportunity to flush their caches.
         */
-       if (error == 0 && ko->ko_text_address != 0) {
+       if (ko->ko_text_address != 0) {
                error = kobj_machdep(ko, (void *)ko->ko_text_address,
                    ko->ko_text_size, true);
-               if (error != 0)
+               if (error) {
                        kobj_error(ko, "machine dependent init failed (text)"
                            " %d", error);
+                       goto out;
+               }
        }
 
-       if (error == 0 && ko->ko_data_address != 0) {
+       if (ko->ko_data_address != 0) {
                error = kobj_machdep(ko, (void *)ko->ko_data_address,
                    ko->ko_data_size, true);
-               if (error != 0)
+               if (error) {
                        kobj_error(ko, "machine dependent init failed (data)"
                            " %d", error);
+                       goto out;
+               }
        }
 
-       if (error == 0 && ko->ko_rodata_address != 0) {
+       if (ko->ko_rodata_address != 0) {
                error = kobj_machdep(ko, (void *)ko->ko_rodata_address,
                    ko->ko_rodata_size, true);
-               if (error != 0)
+               if (error) {
                        kobj_error(ko, "machine dependent init failed (rodata)"
                            " %d", error);
+                       goto out;
+               }
        }
 
-       if (error == 0) {
-               ko->ko_loaded = true;
+       ko->ko_loaded = true;
 
-               /* Change the memory protections, when needed. */
-               if (ko->ko_text_address != 0) {
-                       uvm_km_protect(module_map, ko->ko_text_address,
-                            ko->ko_text_size, VM_PROT_READ|VM_PROT_EXECUTE);
-               }
-               if (ko->ko_rodata_address != 0) {
-                       uvm_km_protect(module_map, ko->ko_rodata_address,
-                           ko->ko_rodata_size, VM_PROT_READ);
-               }
-       } else {
+       /* Change the memory protections, when needed. */
+       if (ko->ko_text_address != 0) {
+               uvm_km_protect(module_map, ko->ko_text_address,
+                   ko->ko_text_size, VM_PROT_READ|VM_PROT_EXECUTE);
+       }
+       if (ko->ko_rodata_address != 0) {
+               uvm_km_protect(module_map, ko->ko_rodata_address,
+                   ko->ko_rodata_size, VM_PROT_READ);
+       }
+
+       /* Success! */
+       error = 0;
+
+out:   if (error) {
                /* If there was an error, destroy the whole object. */
                kobj_unload(ko);
        }
-
        return error;
 }