block: use int to store blk_stack_limits() return value

[ Upstream commit b0b4518c992eb5f316c6e40ff186cbb7a5009518 ]

Change the 'ret' variable in blk_stack_limits() from unsigned int to int,
as it needs to store negative value -1.

Storing the negative error codes in unsigned type, or performing equality
comparisons (e.g., ret == -1), doesn't cause an issue at runtime [1] but
can be confusing.  Additionally, assigning negative error codes to unsigned
type may trigger a GCC warning when the -Wsign-conversion flag is enabled.

No effect on runtime.

Link: https://lore.kernel.org/all/x3wogjf6vgpkisdhg3abzrx7v7zktmdnfmqeih5kosszmagqfs@oh3qxrgzkikf/ #1
Signed-off-by: Qianfeng Rong <[email protected]>
Reviewed-by: John Garry <[email protected]>
Fixes: fe0b393 ("block: Correct handling of bottom device misaligment")
Reviewed-by: Bart Van Assche <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
(cherry picked from commit 48d6e1424cb1ebac1f56d53dc0f278213f18c587)
Signed-off-by: Alok Tiwari <[email protected]>

Author: qianfengrong

block/blk-settings.c

@@ -503,7 +503,8 @@ static unsigned int blk_round_down_sectors(unsigned int sectors, unsigned int lb
 int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 		     sector_t start)
 {
-	unsigned int top, bottom, alignment, ret = 0;
+	unsigned int top, bottom, alignment;
+	int ret = 0;
 
 	t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors);
 	t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors);