[PATCH] md: don't add empty badblocks record table in super_1_load()

[colyli@fnnas.com]

From: Coly Li <colyli@fnnas.com>

In super_1_load() when badblocks table is loaded from component disk,
current code adds all records including empty ones into in-memory
badblocks table. Because empty record's sectors count is 0, calling
badblocks_set() with parameter sectors=0 will return -EINVAL. This isn't
expected behavior and adding a correct component disk into the array
will incorrectly fail.

This patch fixes the issue by checking the badblock record before call-
ing badblocks_set(). If this badblock record is empty (bb == 0), then
skip this one and continue to try next bad record.

Signed-off-by: Coly Li <colyli@fnnas.com>
---
 drivers/md/md.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 41c476b40c7a..b4b5799b4f9f 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1873,9 +1873,14 @@ static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_
 		bbp = (__le64 *)page_address(rdev->bb_page);
 		rdev->badblocks.shift = sb->bblog_shift;
 		for (i = 0 ; i < (sectors << (9-3)) ; i++, bbp++) {
-			u64 bb = le64_to_cpu(*bbp);
-			int count = bb & (0x3ff);
-			u64 sector = bb >> 10;
+			u64 bb, sector;
+			int count;
+
+			bb = le64_to_cpu(*bbp);
+			if (bb == 0)
+				continue;
+			count = bb & (0x3ff);
+			sector = bb >> 10;
 			sector <<= sb->bblog_shift;
 			count <<= sb->bblog_shift;
 			if (bb + 1 == 0)
-- 
2.47.3