block: Make ioprio_best() static

Nobody outside of block/ioprio.c uses it.
Reviewed-by: NDamien Le Moal <damien.lemoal@opensource.wdc.com>
Tested-by: NDamien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220623074840.5960-4-jack@suse.czSigned-off-by: NJens Axboe <axboe@kernel.dk>

block/ioprio.c

@@ -180,7 +180,7 @@ static int get_task_ioprio(struct task_struct *p)
 	return ret;
 }
 
-int ioprio_best(unsigned short aprio, unsigned short bprio)
+static int ioprio_best(unsigned short aprio, unsigned short bprio)
 {
 	if (!ioprio_valid(aprio))
 		aprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, IOPRIO_BE_NORM);

include/linux/ioprio.h

@@ -60,11 +60,6 @@ static inline int get_current_ioprio(void)
 	return __get_task_ioprio(current);
 }
 
-/*
- * For inheritance, return the highest of the two given priorities
- */
-extern int ioprio_best(unsigned short aprio, unsigned short bprio);
-
 extern int set_task_ioprio(struct task_struct *task, int ioprio);
 
 #ifdef CONFIG_BLOCK