kexec: do a cleanup for function kexec_load

There are a lof of work to be done in function kexec_load, not only for
allocating structs and loading initram, but also for some misc.

To make it more clear, wrap a new function do_kexec_load which is used
to allocate structs and load initram.  And the pre-work will be done in
kexec_load.

Signed-off-by: Minfei Huang <mnfhuang@gmail.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Xunlei Pang <xlpang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/kexec.c b/kernel/kexec.c
index 4b49aa7..b73dc21 100644 (file)
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -103,6 +103,74 @@ out_free_image:
        return ret;
 }
 
+static int do_kexec_load(unsigned long entry, unsigned long nr_segments,
+               struct kexec_segment __user *segments, unsigned long flags)
+{
+       struct kimage **dest_image, *image;
+       unsigned long i;
+       int ret;
+
+       if (flags & KEXEC_ON_CRASH) {
+               dest_image = &kexec_crash_image;
+               if (kexec_crash_image)
+                       arch_kexec_unprotect_crashkres();
+       } else {
+               dest_image = &kexec_image;
+       }
+
+       if (nr_segments == 0) {
+               /* Uninstall image */
+               kimage_free(xchg(dest_image, NULL));
+               return 0;
+       }
+       if (flags & KEXEC_ON_CRASH) {
+               /*
+                * Loading another kernel to switch to if this one
+                * crashes.  Free any current crash dump kernel before
+                * we corrupt it.
+                */
+               kimage_free(xchg(&kexec_crash_image, NULL));
+       }
+
+       ret = kimage_alloc_init(&image, entry, nr_segments, segments, flags);
+       if (ret)
+               return ret;
+
+       if (flags & KEXEC_ON_CRASH)
+               crash_map_reserved_pages();
+
+       if (flags & KEXEC_PRESERVE_CONTEXT)
+               image->preserve_context = 1;
+
+       ret = machine_kexec_prepare(image);
+       if (ret)
+               goto out;
+
+       for (i = 0; i < nr_segments; i++) {
+               ret = kimage_load_segment(image, &image->segment[i]);
+               if (ret)
+                       goto out;
+       }
+
+       kimage_terminate(image);
+
+       /* Install the new kernel and uninstall the old */
+       image = xchg(dest_image, image);
+
+out:
+       if ((flags & KEXEC_ON_CRASH) && kexec_crash_image)
+               arch_kexec_protect_crashkres();
+
+       /*
+        * Once the reserved memory is mapped, we should unmap this memory
+        * before returning
+        */
+       if (flags & KEXEC_ON_CRASH)
+               crash_unmap_reserved_pages();
+       kimage_free(image);
+       return ret;
+}
+
 /*
  * Exec Kernel system call: for obvious reasons only root may call it.
  *
@@ -127,7 +195,6 @@ out_free_image:
 SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
                struct kexec_segment __user *, segments, unsigned long, flags)
 {
-       struct kimage **dest_image, *image;
        int result;
 
        /* We only trust the superuser with rebooting the system. */
@@ -152,9 +219,6 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
        if (nr_segments > KEXEC_SEGMENT_MAX)
                return -EINVAL;
 
-       image = NULL;
-       result = 0;
-
        /* Because we write directly to the reserved memory
         * region when loading crash kernels we need a mutex here to
         * prevent multiple crash  kernels from attempting to load
@@ -166,63 +230,12 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
        if (!mutex_trylock(&kexec_mutex))
                return -EBUSY;
 
-       dest_image = &kexec_image;
-       if (flags & KEXEC_ON_CRASH) {
-               dest_image = &kexec_crash_image;
-               if (kexec_crash_image)
-                       arch_kexec_unprotect_crashkres();
-       }
-
-       if (nr_segments > 0) {
-               unsigned long i;
-
-               if (flags & KEXEC_ON_CRASH) {
-                       /*
-                        * Loading another kernel to switch to if this one
-                        * crashes.  Free any current crash dump kernel before
-                        * we corrupt it.
-                        */
-
-                       kimage_free(xchg(&kexec_crash_image, NULL));
-                       result = kimage_alloc_init(&image, entry, nr_segments,
-                                                  segments, flags);
-                       crash_map_reserved_pages();
-               } else {
-                       /* Loading another kernel to reboot into. */
-
-                       result = kimage_alloc_init(&image, entry, nr_segments,
-                                                  segments, flags);
-               }
-               if (result)
-                       goto unmap_page;
-
-               if (flags & KEXEC_PRESERVE_CONTEXT)
-                       image->preserve_context = 1;
-               result = machine_kexec_prepare(image);
-               if (result)
-                       goto unmap_page;
-
-               for (i = 0; i < nr_segments; i++) {
-                       result = kimage_load_segment(image, &image->segment[i]);
-                       if (result)
-                               goto unmap_page;
-               }
-               kimage_terminate(image);
-unmap_page:
-               if (flags & KEXEC_ON_CRASH)
-                       crash_unmap_reserved_pages();
-               if (result)
-                       goto out;
-       }
-       /* Install the new kernel, and  Uninstall the old */
-       image = xchg(dest_image, image);
+       result = do_kexec_load(entry, nr_segments, segments, flags);
 
-out:
        if ((flags & KEXEC_ON_CRASH) && kexec_crash_image)
                arch_kexec_protect_crashkres();
 
        mutex_unlock(&kexec_mutex);
-       kimage_free(image);
 
        return result;
 }