linux-kernel - [PATCH v3] block/blk-iocost (gcc13): keep large values in a new enum

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Date:   Tue, 13 Dec 2022 13:08:26 +0100
From:   "Jiri Slaby (SUSE)" <jirislaby@...nel.org>
To:     Tejun Heo <tj@...nel.org>
Cc:     linux-kernel@...r.kernel.org,
        "Jiri Slaby (SUSE)" <jirislaby@...nel.org>,
        Martin Liska <mliska@...e.cz>,
        Josef Bacik <josef@...icpanda.com>,
        Jens Axboe <axboe@...nel.dk>, cgroups@...r.kernel.org,
        linux-block@...r.kernel.org
Subject: [PATCH v3] block/blk-iocost (gcc13): keep large values in a new enum

Since gcc13, each member of an enum has the same type as the enum [1]. And
that is inherited from its members. Provided:
  VTIME_PER_SEC_SHIFT     = 37,
  VTIME_PER_SEC           = 1LLU << VTIME_PER_SEC_SHIFT,
  ...
  AUTOP_CYCLE_NSEC        = 10LLU * NSEC_PER_SEC,
the named type is unsigned long.

This generates warnings with gcc-13:
  block/blk-iocost.c: In function 'ioc_weight_prfill':
  block/blk-iocost.c:3037:37: error: format '%u' expects argument of type 'unsigned int', but argument 4 has type 'long unsigned int'

  block/blk-iocost.c: In function 'ioc_weight_show':
  block/blk-iocost.c:3047:34: error: format '%u' expects argument of type 'unsigned int', but argument 3 has type 'long unsigned int'

So split the anonumois enum with large values to a separate enum, so
that they don't affect other members.

[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=36113

Cc: Martin Liska <mliska@...e.cz>
Cc: Tejun Heo <tj@...nel.org>
Cc: Josef Bacik <josef@...icpanda.com>
Cc: Jens Axboe <axboe@...nel.dk>
Cc: cgroups@...r.kernel.org
Cc: linux-block@...r.kernel.org
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@...nel.org>
---

Notes:
    [v3] move more to a new enum (effectively split the enums)
    [v2] move to a new enum

 block/blk-iocost.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index d1bdc12deaa7..549ddc9e0c6f 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -232,7 +232,9 @@ enum {
 
 	/* 1/64k is granular enough and can easily be handled w/ u32 */
 	WEIGHT_ONE		= 1 << 16,
+};
 
+enum {
 	/*
 	 * As vtime is used to calculate the cost of each IO, it needs to
 	 * be fairly high precision.  For example, it should be able to
-- 
2.39.0