initramfs: support initramfs that is bigger than 2GiB

Now with 64bit bzImage and kexec tools, we support ramdisk that size is
bigger than 2g, as we could put it above 4G.

Found compressed initramfs image could not be decompressed properly.  It
turns out that image length is int during decompress detection, and it
will become < 0 when length is more than 2G.  Furthermore, during
decompressing len as int is used for inbuf count, that has problem too.

Change len to long, that should be ok as on 32 bit platform long is
32bits.

Tested with following compressed initramfs image as root with kexec.
	gzip, bzip2, xz, lzma, lzop, lz4.
run time for populate_rootfs():
   size        name       Nehalem-EX  Westmere-EX  Ivybridge-EX
 9034400256 root_img     :   26s           24s          30s
 3561095057 root_img.lz4 :   28s           27s          27s
 3459554629 root_img.lzo :   29s           29s          28s
 3219399480 root_img.gz  :   64s           62s          49s
 2251594592 root_img.xz  :  262s          260s         183s
 2226366598 root_img.lzma:  386s          376s         277s
 2901482513 root_img.bz2 :  635s          599s

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Rashika Kheria <rashika.kheria@gmail.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Kyungsik Lee <kyungsik.lee@lge.com>
Cc: P J P <ppandit@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: "Daniel M. Weeks" <dan@danweeks.net>
Cc: Alexandre Courbot <acourbot@nvidia.com>
Cc: Jan Beulich <JBeulich@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/lib/decompress_unlzma.c b/lib/decompress_unlzma.c
index 32adb73..0be83af 100644
--- a/lib/decompress_unlzma.c
+++ b/lib/decompress_unlzma.c
@@ -65,11 +65,11 @@
 #define LZMA_IOBUF_SIZE	0x10000
 
 struct rc {
-	int (*fill)(void*, unsigned int);
+	long (*fill)(void*, unsigned long);
 	uint8_t *ptr;
 	uint8_t *buffer;
 	uint8_t *buffer_end;
-	int buffer_size;
+	long buffer_size;
 	uint32_t code;
 	uint32_t range;
 	uint32_t bound;
@@ -82,7 +82,7 @@
 #define RC_MODEL_TOTAL_BITS 11
 
 
-static int INIT nofill(void *buffer, unsigned int len)
+static long INIT nofill(void *buffer, unsigned long len)
 {
 	return -1;
 }
@@ -99,8 +99,8 @@
 
 /* Called once */
 static inline void INIT rc_init(struct rc *rc,
-				       int (*fill)(void*, unsigned int),
-				       char *buffer, int buffer_size)
+				       long (*fill)(void*, unsigned long),
+				       char *buffer, long buffer_size)
 {
 	if (fill)
 		rc->fill = fill;
@@ -280,7 +280,7 @@
 	size_t buffer_pos;
 	int bufsize;
 	size_t global_pos;
-	int(*flush)(void*, unsigned int);
+	long (*flush)(void*, unsigned long);
 	struct lzma_header *header;
 };
 
@@ -534,11 +534,11 @@
 
 
 
-STATIC inline int INIT unlzma(unsigned char *buf, int in_len,
-			      int(*fill)(void*, unsigned int),
-			      int(*flush)(void*, unsigned int),
+STATIC inline int INIT unlzma(unsigned char *buf, long in_len,
+			      long (*fill)(void*, unsigned long),
+			      long (*flush)(void*, unsigned long),
 			      unsigned char *output,
-			      int *posp,
+			      long *posp,
 			      void(*error)(char *x)
 	)
 {
@@ -667,11 +667,11 @@
 }
 
 #ifdef PREBOOT
-STATIC int INIT decompress(unsigned char *buf, int in_len,
-			      int(*fill)(void*, unsigned int),
-			      int(*flush)(void*, unsigned int),
+STATIC int INIT decompress(unsigned char *buf, long in_len,
+			      long (*fill)(void*, unsigned long),
+			      long (*flush)(void*, unsigned long),
 			      unsigned char *output,
-			      int *posp,
+			      long *posp,
 			      void(*error)(char *x)
 	)
 {