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scsi: block: Improve ioprio value validity checks

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The introduction of the macro IOPRIO_PRIO_LEVEL() in commit eca2040972
("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: 6c91325722 ("scsi: block: Introduce ioprio hints")
Fixes: eca2040972 ("scsi: block: ioprio: Clean up interface definition")
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230608095556.124001-1-dlemoal@kernel.org
Reviewed-by: Niklas Cassel <niklas.cassel@wdc.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Damien Le Moal 2023-06-08 18:55:56 +09:00 committed by Martin K. Petersen
parent 022000d3f5
commit 01584c1e23
2 changed files with 34 additions and 17 deletions
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1
block/ioprio.c
View File

@ -58,6 +58,7 @@ int ioprio_check_cap(int ioprio)
if (level)
return -EINVAL;
break;
case IOPRIO_CLASS_INVALID:
default:
return -EINVAL;
}

50
include/uapi/linux/ioprio.h
View File

@ -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 */