Changeset 9da567b2 in rtems

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@…>
Cc: "H. Peter Anvin" <hpa@…>
Cc: Ingo Molnar <mingo@…>
Cc: Rashika Kheria <rashika.kheria@…>
Cc: Josh Triplett <josh@…>
Cc: Kyungsik Lee <kyungsik.lee@…>
Cc: P J P <ppandit@…>
Cc: Al Viro <viro@…>
Cc: Tetsuo Handa <penguin-kernel@…>
Cc: "Daniel M. Weeks" <dan@…>
Cc: Alexandre Courbot <acourbot@…>
Cc: Jan Beulich <JBeulich@…>
Signed-off-by: Andrew Morton <akpm@…>
Signed-off-by: Linus Torvalds <torvalds@…>