On 7/31/24 16:01, Zhiguo Niu wrote: > Generally, the input of IOPRIO_PRIO_DATA has 16 bits, but the output of > IOPRIO_PRIO_DATA will be expanded to "UL" from IOPRIO_PRIO_MASK. > #define IOPRIO_PRIO_MASK ((1UL << IOPRIO_CLASS_SHIFT) - 1) > This is not reasonable and meaningless, unsigned int is more suitable for it. > > So if use format "%d" to print IOPRIO_PRIO_DATA directly, there will be a > build warning or error showned as the following, which is from the > local test when I modify f2fs codes. > > fs/f2fs/sysfs.c:348:31: warning: format ‘%d’ expects argument of type ‘int’, > but argument 4 has type ‘long unsigned int’ [-Wformat=] > return sysfs_emit(buf, "%s,%d\n", > ~^ > %ld > > When modules use IOPRIO_PRIO_CLASS & IOPRIO_PRIO_LEVEL get ioprio's class and > level, their outputs are both unsigned int. > IOPRIO_CLASS_MASK is: > #define IOPRIO_CLASS_SHIFT 13 > #define IOPRIO_NR_CLASSES 8 > #define IOPRIO_CLASS_MASK (IOPRIO_NR_CLASSES - 1) > IOPRIO_LEVEL_MASK is: > #define IOPRIO_LEVEL_NR_BITS 3 > #define IOPRIO_NR_LEVELS (1 << IOPRIO_LEVEL_NR_BITS) > #define IOPRIO_LEVEL_MASK (IOPRIO_NR_LEVELS - 1) > > Ioprio is passed along as an int internally, so we should not be using an > unsigned long for IOPRIO_PRIO_MASK to not end up with IOPRIO_PRIO_DATA > returning an unsigned long as well. I would write this commit message like this: An ioprio is passed internally as an int value. When IOPRIO_PRIO_CLASS() and IOPRIO_PRIO_LEVEL() are used to extract from it the priority class and level, the values obtained are thus also int. However, the IOPRIO_PRIO_MASK() macro used to define the IOPRIO_PRIO_DATA() macro is defined as: #define IOPRIO_PRIO_MASK ((1UL << IOPRIO_CLASS_SHIFT) - 1) that is, the macro gives an unsigned long value, which leads to IOPRIO_PRIO_DATA() also returning an unsigned long. Make things consistent between class, level and data and use int everywhere by removing forced unsigned long from IOPRIO_PRIO_MASK. -- Damien Le Moal Western Digital Research
