Commit 01584c1e authored by Damien Le Moal's avatar Damien Le Moal Committed by Martin K. Petersen
Browse files

scsi: block: Improve ioprio value validity checks 



The introduction of the macro IOPRIO_PRIO_LEVEL() in commit eca20409
("scsi: block: ioprio: Clean up interface definition") results in an
iopriority level to always be masked using the macro IOPRIO_LEVEL_MASK, and
thus to the kernel always seeing an acceptable value for an I/O priority
level when checked in ioprio_check_cap().  Before this patch, this function
would return an error for some (but not all) invalid values for a level
valid range of [0..7].

Restore and improve the detection of invalid priority levels by introducing
the inline function ioprio_value() to check an ioprio class, level and hint
value before combining these fields into a single value to be used with
ioprio_set() or AIOs. If an invalid value for the class, level or hint of
an ioprio is detected, ioprio_value() returns an ioprio using the class
IOPRIO_CLASS_INVALID, indicating an invalid value and causing
ioprio_check_cap() to return -EINVAL.

Fixes: 6c913257 ("scsi: block: Introduce ioprio hints")
Fixes: eca20409 ("scsi: block: ioprio: Clean up interface definition")
Signed-off-by: default avatarDamien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230608095556.124001-1-dlemoal@kernel.org


Reviewed-by: default avatarNiklas Cassel <niklas.cassel@wdc.com>
Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 022000d3

block/ioprio.c

+1 −0
Original line number Diff line number Diff line
@@ -58,6 +58,7 @@ int ioprio_check_cap(int ioprio) 
			if (level)

				return -EINVAL;

			break;

		case IOPRIO_CLASS_INVALID:

		default:

			return -EINVAL;

	}

include/uapi/linux/ioprio.h

+33 −17
Original line number Diff line number Diff line
@@ -2,19 +2,20 @@ 
#ifndef _UAPI_LINUX_IOPRIO_H

#define _UAPI_LINUX_IOPRIO_H



#include <linux/stddef.h>

#include <linux/types.h>



/*

 * Gives us 8 prio classes with 13-bits of data for each class

 */

#define IOPRIO_CLASS_SHIFT	13

#define IOPRIO_CLASS_MASK	0x07

#define IOPRIO_NR_CLASSES	8

#define IOPRIO_CLASS_MASK	(IOPRIO_NR_CLASSES - 1)

#define IOPRIO_PRIO_MASK	((1UL << IOPRIO_CLASS_SHIFT) - 1)



#define IOPRIO_PRIO_CLASS(ioprio)	\

	(((ioprio) >> IOPRIO_CLASS_SHIFT) & IOPRIO_CLASS_MASK)

#define IOPRIO_PRIO_DATA(ioprio)	((ioprio) & IOPRIO_PRIO_MASK)

#define IOPRIO_PRIO_VALUE(class, data)	\

	((((class) & IOPRIO_CLASS_MASK) << IOPRIO_CLASS_SHIFT) | \

	 ((data) & IOPRIO_PRIO_MASK))



/*

 * These are the io priority classes as implemented by the BFQ and mq-deadline
@@ -25,10 +26,13 @@ 
 * served when no one else is using the disk.

 */

enum {

	IOPRIO_CLASS_NONE,

	IOPRIO_CLASS_RT,

	IOPRIO_CLASS_BE,

	IOPRIO_CLASS_IDLE,

	IOPRIO_CLASS_NONE	= 0,

	IOPRIO_CLASS_RT		= 1,

	IOPRIO_CLASS_BE		= 2,

	IOPRIO_CLASS_IDLE	= 3,



	/* Special class to indicate an invalid ioprio value */

	IOPRIO_CLASS_INVALID	= 7,

};



/*
@@ -73,15 +77,6 @@ enum { 
#define IOPRIO_PRIO_HINT(ioprio)	\

	(((ioprio) >> IOPRIO_HINT_SHIFT) & IOPRIO_HINT_MASK)



/*

 * Alternate macro for IOPRIO_PRIO_VALUE() to define an I/O priority with

 * a class, level and hint.

 */

#define IOPRIO_PRIO_VALUE_HINT(class, level, hint)		 \

	((((class) & IOPRIO_CLASS_MASK) << IOPRIO_CLASS_SHIFT) | \

	 (((hint) & IOPRIO_HINT_MASK) << IOPRIO_HINT_SHIFT) |	 \

	 ((level) & IOPRIO_LEVEL_MASK))



/*

 * I/O hints.

 */
@@ -107,4 +102,25 @@ enum { 
	IOPRIO_HINT_DEV_DURATION_LIMIT_7 = 7,

};



#define IOPRIO_BAD_VALUE(val, max) ((val) < 0 || (val) >= (max))



/*

 * Return an I/O priority value based on a class, a level and a hint.

 */

static __always_inline __u16 ioprio_value(int class, int level, int hint)

{

	if (IOPRIO_BAD_VALUE(class, IOPRIO_NR_CLASSES) ||

	    IOPRIO_BAD_VALUE(level, IOPRIO_NR_LEVELS) ||

	    IOPRIO_BAD_VALUE(hint, IOPRIO_NR_HINTS))

		return IOPRIO_CLASS_INVALID << IOPRIO_CLASS_SHIFT;



	return (class << IOPRIO_CLASS_SHIFT) |

		(hint << IOPRIO_HINT_SHIFT) | level;

}



#define IOPRIO_PRIO_VALUE(class, level)			\

	ioprio_value(class, level, IOPRIO_HINT_NONE)

#define IOPRIO_PRIO_VALUE_HINT(class, level, hint)	\

	ioprio_value(class, level, hint)



#endif /* _UAPI_LINUX_IOPRIO_H */