initramfs: cleanup populate_rootfs

The code for kernels that support ramdisks or not is mostly the same.
Unify it by using an IS_ENABLED for the info message, and moving the error
message into a stub for populate_initrd_image.

[cai@lca.pw: fix a compilation error]
  Link: http://lkml.kernel.org/r/20190328014806.36375-1-cai@lca.pw
Link: http://lkml.kernel.org/r/20190213174621.29297-6-hch@lst.deSigned-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Qian Cai <cai@lca.pw>
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>

init/initramfs.c

@@ -595,7 +595,11 @@ static void __init clean_rootfs(void)
 	ksys_close(fd);
 	kfree(buf);
 }
-#endif
+#else
+static inline void clean_rootfs(void)
+{
+}
+#endif /* CONFIG_BLK_DEV_RAM */
 
 #ifdef CONFIG_BLK_DEV_RAM
 static void populate_initrd_image(char *err)
@@ -617,6 +621,11 @@ static void populate_initrd_image(char *err)
 		       written, initrd_end - initrd_start);
 	ksys_close(fd);
 }
+#else
+static void populate_initrd_image(char *err)
+{
+	printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
+}
 #endif /* CONFIG_BLK_DEV_RAM */
 
 static int __init populate_rootfs(void)
@@ -625,28 +634,22 @@ static int __init populate_rootfs(void)
 	char *err = unpack_to_rootfs(__initramfs_start, __initramfs_size);
 	if (err)
 		panic("%s", err); /* Failed to decompress INTERNAL initramfs */
-	/* If available load the bootloader supplied initrd */
-	if (initrd_start && !IS_ENABLED(CONFIG_INITRAMFS_FORCE)) {
-#ifdef CONFIG_BLK_DEV_RAM
+
+	if (!initrd_start || IS_ENABLED(CONFIG_INITRAMFS_FORCE))
+		goto done;
+
+	if (IS_ENABLED(CONFIG_BLK_DEV_RAM))
 		printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");
-		err = unpack_to_rootfs((char *)initrd_start,
-			initrd_end - initrd_start);
-		if (!err)
-			goto done;
+	else
+		printk(KERN_INFO "Unpacking initramfs...\n");
 
+	err = unpack_to_rootfs((char *)initrd_start, initrd_end - initrd_start);
+	if (err) {
 		clean_rootfs();
 		populate_initrd_image(err);
-	done:
-		/* empty statement */;
-#else
-		printk(KERN_INFO "Unpacking initramfs...\n");
-		err = unpack_to_rootfs((char *)initrd_start,
-			initrd_end - initrd_start);
-		if (err)
-			printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
-#endif
 	}
 
+done:
 	/*
 	 * If the initrd region is overlapped with crashkernel reserved region,
 	 * free only memory that is not part of crashkernel region.