badblocks: fix the using of MAX_BADBLOCKS

The number of badblocks cannot exceed MAX_BADBLOCKS, but it should be
allowed to equal MAX_BADBLOCKS.

Fixes: aa511ff ("badblocks: switch to the improved badblock handling code")
Fixes: c3c6a86 ("badblocks: add helper routines for badblock ranges handling")
Signed-off-by: Li Nan <[email protected]>
Reviewed-by: Zhu Yanjun <[email protected]>
Reviewed-by: Yu Kuai <[email protected]>
Acked-by: Coly Li <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

Author: Li Nan

block/badblocks.c

@@ -700,7 +700,7 @@ static bool can_front_overwrite(struct badblocks *bb, int prev,
 			*extra = 2;
 	}
 
-	if ((bb->count + (*extra)) >= MAX_BADBLOCKS)
+	if ((bb->count + (*extra)) > MAX_BADBLOCKS)
 		return false;
 
 	return true;
@@ -1135,7 +1135,7 @@ static int _badblocks_clear(struct badblocks *bb, sector_t s, int sectors)
 		if ((BB_OFFSET(p[prev]) < bad.start) &&
 		    (BB_END(p[prev]) > (bad.start + bad.len))) {
 			/* Splitting */
-			if ((bb->count + 1) < MAX_BADBLOCKS) {
+			if ((bb->count + 1) <= MAX_BADBLOCKS) {
 				len = front_splitting_clear(bb, prev, &bad);
 				bb->count += 1;
 				cleared++;