crash_core: fix the check for whether crashkernel is from high memory

If crash_base is equal to CRASH_ADDR_LOW_MAX, it also indicates that
the crashkernel memory is allocated from high memory. However, the
current check only considers the case where crash_base is greater than
CRASH_ADDR_LOW_MAX. Fix it.

The runtime effects is that crashkernel high memory is successfully
reserved, whereas the crashkernel low memory is bypassed in this case,
then kdump kernel bootup will fail because of no low memory under 4G.

This patch also includes some minor cleanups.

Link: https://lkml.kernel.org/r/20231209141438.77233-1-ytcoode@gmail.com
Fixes: 0ab97169 ("crash_core: add generic function to do reservation")
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kernel/crash_core.c

@@ -199,7 +199,7 @@ static __initdata char *suffix_tbl[] = {
  * It returns 0 on success and -EINVAL on failure.
  */
 static int __init parse_crashkernel_suffix(char *cmdline,
-					   unsigned long long	*crash_size,
+					   unsigned long long *crash_size,
 					   const char *suffix)
 {
 	char *cur = cmdline;
@@ -268,9 +268,9 @@ static int __init __parse_crashkernel(char *cmdline,
 			     unsigned long long *crash_base,
 			     const char *suffix)
 {
-	char	*first_colon, *first_space;
-	char	*ck_cmdline;
-	char	*name = "crashkernel=";
+	char *first_colon, *first_space;
+	char *ck_cmdline;
+	char *name = "crashkernel=";
 
 	BUG_ON(!crash_size || !crash_base);
 	*crash_size = 0;
@@ -440,7 +440,7 @@ void __init reserve_crashkernel_generic(char *cmdline,
 		return;
 	}
 
-	if ((crash_base > CRASH_ADDR_LOW_MAX) &&
+	if ((crash_base >= CRASH_ADDR_LOW_MAX) &&
 	     crash_low_size && reserve_crashkernel_low(crash_low_size)) {
 		memblock_phys_free(crash_base, crash_size);
 		return;