initramfs: cleanup initrd freeing

Factor the kexec logic into a separate helper, and then inline the rest of
free_initrd into the only caller.

Link: http://lkml.kernel.org/r/20190213174621.29297-4-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>	[arm64]
Cc: Geert Uytterhoeven <geert@linux-m68k.org>	[m68k]
Cc: Steven Price <steven.price@arm.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 30 insertions, 23 deletions

diff --git a/init/initramfs.c b/init/initramfs.c
index c322e1099f43..5fda9557a134 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -518,37 +518,35 @@ extern unsigned long __initramfs_size;
 #include <linux/initrd.h>
 #include <linux/kexec.h>
 
-static void __init free_initrd(void)
-{
 #ifdef CONFIG_KEXEC_CORE
+static bool kexec_free_initrd(void)
+{
         unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
         unsigned long crashk_end   = (unsigned long)__va(crashk_res.end);
-#endif
-        if (do_retain_initrd)
-                goto skip;
 
-#ifdef CONFIG_KEXEC_CORE
         /*
          * If the initrd region is overlapped with crashkernel reserved region,
          * free only memory that is not part of crashkernel region.
          */
-        if (initrd_start < crashk_end && initrd_end > crashk_start) {
-                /*
-                 * Initialize initrd memory region since the kexec boot does
-                 * not do.
-                 */
-                memset((void *)initrd_start, 0, initrd_end - initrd_start);
-                if (initrd_start < crashk_start)
-                        free_initrd_mem(initrd_start, crashk_start);
-                if (initrd_end > crashk_end)
-                        free_initrd_mem(crashk_end, initrd_end);
-        } else
-#endif
-                free_initrd_mem(initrd_start, initrd_end);
-skip:
-        initrd_start = 0;
-        initrd_end = 0;
+        if (initrd_start >= crashk_end || initrd_end <= crashk_start)
+                return false;
+
+        /*
+         * Initialize initrd memory region since the kexec boot does not do.
+         */
+        memset((void *)initrd_start, 0, initrd_end - initrd_start);
+        if (initrd_start < crashk_start)
+                free_initrd_mem(initrd_start, crashk_start);
+        if (initrd_end > crashk_end)
+                free_initrd_mem(crashk_end, initrd_end);
+        return true;
 }
+#else
+static inline bool kexec_free_initrd(void)
+{
+        return false;
+}
+#endif /* CONFIG_KEXEC_CORE */
 
 #ifdef CONFIG_BLK_DEV_RAM
 #define BUF_SIZE 1024
@@ -642,7 +640,16 @@ static int __init populate_rootfs(void)
                         printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
 #endif
         }
-        free_initrd();
+
+        /*
+         * If the initrd region is overlapped with crashkernel reserved region,
+         * free only memory that is not part of crashkernel region.
+         */
+        if (!do_retain_initrd && !kexec_free_initrd())
+                free_initrd_mem(initrd_start, initrd_end);
+        initrd_start = 0;
+        initrd_end = 0;
+
         flush_delayed_fput();
         return 0;
 }