Re: [PATCH v2 03/15] block: Support data lifetime in the I/O priority bitfield

[Kanchan Joshi <joshi.k@samsung.com>]

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On Thu, Oct 05, 2023 at 12:40:49PM -0700, Bart Van Assche wrote:
>The NVMe and SCSI standards define 64 different data lifetimes. Support
>storing this information in the I/O priority bitfield.
>
>The current allocation of the 16 bits in the I/O priority bitfield is as
>follows:
>* 15..13: I/O priority class
>* 12..6: unused
>* 5..3: I/O hint (CDL)
>* 2..0: I/O priority level
>
>This patch changes this into the following:
>* 15..13: I/O priority class
>* 12: unused
>* 11..6: data lifetime
>* 5..3: I/O hint (CDL)
>* 2..0: I/O priority level
>
>Cc: Damien Le Moal <dlemoal@kernel.org>
>Cc: Niklas Cassel <niklas.cassel@wdc.com>
>Signed-off-by: Bart Van Assche <bvanassche@acm.org>
>---
> include/uapi/linux/ioprio.h | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
>diff --git a/include/uapi/linux/ioprio.h b/include/uapi/linux/ioprio.h
>index bee2bdb0eedb..efe9bc450872 100644
>--- a/include/uapi/linux/ioprio.h
>+++ b/include/uapi/linux/ioprio.h
>@@ -71,7 +71,7 @@ enum {
>  * class and level.
>  */
> #define IOPRIO_HINT_SHIFT		IOPRIO_LEVEL_NR_BITS
>-#define IOPRIO_HINT_NR_BITS		10
>+#define IOPRIO_HINT_NR_BITS		3

Should the comment[*] also be modified to reflect this change?

[*]
/*
 * The 10 bits between the priority class and the priority level are used to
 * optionally define I/O hints for any combination of I/O priority class and


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