lib/cmdline.c: add size unit t/p/e to memparse

For modern filesystems such as btrfs, t/p/e size level operations are
common.  add size unit t/p/e parsing to memparse

Signed-off-by: Gui Hecheng <guihc.fnst@cn.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/cmdline.c

@@ -121,11 +121,7 @@ EXPORT_SYMBOL(get_options);
  *	@retptr: (output) Optional pointer to next char after parse completes
  *
  *	Parses a string into a number.  The number stored at @ptr is
- *	potentially suffixed with %K (for kilobytes, or 1024 bytes),
- *	%M (for megabytes, or 1048576 bytes), or %G (for gigabytes, or
- *	1073741824).  If the number is suffixed with K, M, or G, then
- *	the return value is the number multiplied by one kilobyte, one
- *	megabyte, or one gigabyte, respectively.
+ *	potentially suffixed with K, M, G, T, P, E.
  */
 
 unsigned long long memparse(const char *ptr, char **retptr)
@@ -135,6 +131,15 @@ unsigned long long memparse(const char *ptr, char **retptr)
 	unsigned long long ret = simple_strtoull(ptr, &endptr, 0);
 
 	switch (*endptr) {
+	case 'E':
+	case 'e':
+		ret <<= 10;
+	case 'P':
+	case 'p':
+		ret <<= 10;
+	case 'T':
+	case 't':
+		ret <<= 10;
 	case 'G':
 	case 'g':
 		ret <<= 10;