md: avoid warning for 32-bit sector_t (3312c951) · Commits · 戴 / test

When CONFIG_LBDAF is not set, sector_t is only 32-bits wide, which means we cannot have devices with more than 2TB, and the code that is trying to handle compatibility support for large devices in md version 0.90 is meaningless but also causes a compile-time warning: drivers/md/md.c: In function 'super_90_load': drivers/md/md.c:1029:19: warning: large integer implicitly truncated to unsigned type [-Woverflow] drivers/md/md.c: In function 'super_90_rdev_size_change': drivers/md/md.c:1323:17: warning: large integer implicitly truncated to unsigned type [-Woverflow] This adds a check for CONFIG_LBDAF to avoid even getting into this code path, and also adds an explicit cast to let the compiler know it doesn't have to warn about the truncation. Signed-off-by:

Arnd Bergmann <arnd@arndb.de> Signed-off-by:

NeilBrown <neilb@suse.com>

drivers/md/md.c

+6 −4

Original line number	Diff line number	Diff line
		@@ -1026,8 +1026,9 @@ static int super_90_load(struct md_rdev rdev, struct md_rdev refdev, int minor
		* (not needed for Linear and RAID0 as metadata doesn't
		* record this size)
		*/
		if (rdev->sectors >= (2ULL << 32) && sb->level >= 1)
		rdev->sectors = (2ULL << 32) - 2;
		if (IS_ENABLED(CONFIG_LBDAF) && (u64)rdev->sectors >= (2ULL << 32) &&
		sb->level >= 1)
		rdev->sectors = (sector_t)(2ULL << 32) - 2;

		if (rdev->sectors < ((sector_t)sb->size) * 2 && sb->level >= 1)
		/* "this cannot possibly happen" ... */
		@@ -1320,8 +1321,9 @@ super_90_rdev_size_change(struct md_rdev *rdev, sector_t num_sectors)
		/* Limit to 4TB as metadata cannot record more than that.
		* 4TB == 2^32 KB, or 2*2^32 sectors.
		*/
		if (num_sectors >= (2ULL << 32) && rdev->mddev->level >= 1)
		num_sectors = (2ULL << 32) - 2;
		if (IS_ENABLED(CONFIG_LBDAF) && (u64)num_sectors >= (2ULL << 32) &&
		rdev->mddev->level >= 1)
		num_sectors = (sector_t)(2ULL << 32) - 2;
		md_super_write(rdev->mddev, rdev, rdev->sb_start, rdev->sb_size,
		rdev->sb_page);
		md_super_wait(rdev->mddev);

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