x86/setup: simplify handling of initrdidx when no initrd present

Remove a ternary operator that made my brain hurt and replace it with
something simpler that makes it clearer that the >= mbi->mods_count
is because of what find_first_bit() returns when it doesn't find
anything. Just have a simple condition to set initrdidx to zero in
that case, and a much simpler ternary operator in the create_dom0()
call.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>

diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 53f7b9ced4995062eb70b9360bb8ac0ad9decc96..6b3a5777cb5dfac31f10bb537c0584e55c2a7821 100644 (file)
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1993,6 +1993,9 @@ void __init noreturn __start_xen(unsigned long mbi_p)
     else
     {
         initrdidx = find_first_bit(module_map, mbi->mods_count);
+        if ( initrdidx >= mbi->mods_count )
+            initrdidx = 0;
+
         if ( bitmap_weight(module_map, mbi->mods_count) > 1 )
             printk(XENLOG_WARNING
                    "Multiple initrd candidates, picking module #%u\n",
@@ -2002,8 +2005,8 @@ void __init noreturn __start_xen(unsigned long mbi_p)
          * safely above our heap. The second module, if present, is an initrd.
          */
         dom0 = create_dom0(mod, modules_headroom,
-                           (initrdidx > 0) && (initrdidx < mbi->mods_count)
-                           ? mod + initrdidx : NULL, kextra, loader);
+                           initrdidx ? mod + initrdidx : NULL,
+                           kextra, loader);
         if ( dom0 == NULL )
             panic("Could not set up DOM0 guest OS\n");
     }