From: Eliav Farber <farbere@amazon•com>
To: <gregkh@linuxfoundation•org>, <jdike@addtoit•com>,
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Cc: Linus Torvalds <torvalds@linux-foundation•org>,
David Laight <David.Laight@aculab•com>,
Lorenzo Stoakes <lorenzo.stoakes@oracle•com>
Subject: [PATCH 07/19 5.15.y] minmax: add a few more MIN_T/MAX_T users
Date: Thu, 2 Oct 2025 20:47:21 +0000 [thread overview]
Message-ID: <20251002204733.35652-8-farbere@amazon.com> (raw)
In-Reply-To: <20251002204733.35652-1-farbere@amazon.com>
From: Linus Torvalds <torvalds@linux-foundation•org>
commit 4477b39c32fdc03363affef4b11d48391e6dc9ff upstream.
Commit 3a7e02c040b1 ("minmax: avoid overly complicated constant
expressions in VM code") added the simpler MIN_T/MAX_T macros in order
to avoid some excessive expansion from the rather complicated regular
min/max macros.
The complexity of those macros stems from two issues:
(a) trying to use them in situations that require a C constant
expression (in static initializers and for array sizes)
(b) the type sanity checking
and MIN_T/MAX_T avoids both of these issues.
Now, in the whole (long) discussion about all this, it was pointed out
that the whole type sanity checking is entirely unnecessary for
min_t/max_t which get a fixed type that the comparison is done in.
But that still leaves min_t/max_t unnecessarily complicated due to
worries about the C constant expression case.
However, it turns out that there really aren't very many cases that use
min_t/max_t for this, and we can just force-convert those.
This does exactly that.
Which in turn will then allow for much simpler implementations of
min_t()/max_t(). All the usual "macros in all upper case will evaluate
the arguments multiple times" rules apply.
We should do all the same things for the regular min/max() vs MIN/MAX()
cases, but that has the added complexity of various drivers defining
their own local versions of MIN/MAX, so that needs another level of
fixes first.
Link: https://lore.kernel.org/all/b47fad1d0cf8449886ad148f8c013dae@AcuMS.aculab.com/
Cc: David Laight <David.Laight@aculab•com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle•com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation•org>
Signed-off-by: Eliav Farber <farbere@amazon•com>
---
arch/x86/mm/pgtable.c | 2 +-
drivers/edac/sb_edac.c | 4 ++--
drivers/gpu/drm/drm_color_mgmt.c | 2 +-
drivers/md/dm-integrity.c | 2 +-
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 2 +-
net/ipv4/proc.c | 2 +-
net/ipv6/proc.c | 2 +-
7 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 3481b35cb4ec..e649161eb6fc 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -107,7 +107,7 @@ static inline void pgd_list_del(pgd_t *pgd)
#define UNSHARED_PTRS_PER_PGD \
(SHARED_KERNEL_PMD ? KERNEL_PGD_BOUNDARY : PTRS_PER_PGD)
#define MAX_UNSHARED_PTRS_PER_PGD \
- max_t(size_t, KERNEL_PGD_BOUNDARY, PTRS_PER_PGD)
+ MAX_T(size_t, KERNEL_PGD_BOUNDARY, PTRS_PER_PGD)
static void pgd_set_mm(pgd_t *pgd, struct mm_struct *mm)
diff --git a/drivers/edac/sb_edac.c b/drivers/edac/sb_edac.c
index 1522d4aa2ca6..714020e7405a 100644
--- a/drivers/edac/sb_edac.c
+++ b/drivers/edac/sb_edac.c
@@ -109,8 +109,8 @@ static const u32 knl_interleave_list[] = {
0x104, 0x10c, 0x114, 0x11c, /* 20-23 */
};
#define MAX_INTERLEAVE \
- (max_t(unsigned int, ARRAY_SIZE(sbridge_interleave_list), \
- max_t(unsigned int, ARRAY_SIZE(ibridge_interleave_list), \
+ (MAX_T(unsigned int, ARRAY_SIZE(sbridge_interleave_list), \
+ MAX_T(unsigned int, ARRAY_SIZE(ibridge_interleave_list), \
ARRAY_SIZE(knl_interleave_list))))
struct interleave_pkg {
diff --git a/drivers/gpu/drm/drm_color_mgmt.c b/drivers/gpu/drm/drm_color_mgmt.c
index bb14f488c8f6..1ff572d8744e 100644
--- a/drivers/gpu/drm/drm_color_mgmt.c
+++ b/drivers/gpu/drm/drm_color_mgmt.c
@@ -528,7 +528,7 @@ int drm_plane_create_color_properties(struct drm_plane *plane,
{
struct drm_device *dev = plane->dev;
struct drm_property *prop;
- struct drm_prop_enum_list enum_list[max_t(int, DRM_COLOR_ENCODING_MAX,
+ struct drm_prop_enum_list enum_list[MAX_T(int, DRM_COLOR_ENCODING_MAX,
DRM_COLOR_RANGE_MAX)];
int i, len;
diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index e9d553eea9cd..8e2b00536c3e 100644
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -2536,7 +2536,7 @@ static void do_journal_write(struct dm_integrity_c *ic, unsigned write_start,
unlikely(from_replay) &&
#endif
ic->internal_hash) {
- char test_tag[max_t(size_t, HASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)];
+ char test_tag[MAX_T(size_t, HASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)];
integrity_sector_checksum(ic, sec + ((l - j) << ic->sb->log2_sectors_per_block),
(char *)access_journal_data(ic, i, l), test_tag);
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 2478caeec763..21cc8cd9e023 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -2805,7 +2805,7 @@ static void stmmac_dma_interrupt(struct stmmac_priv *priv)
u32 channels_to_check = tx_channel_count > rx_channel_count ?
tx_channel_count : rx_channel_count;
u32 chan;
- int status[max_t(u32, MTL_MAX_TX_QUEUES, MTL_MAX_RX_QUEUES)];
+ int status[MAX_T(u32, MTL_MAX_TX_QUEUES, MTL_MAX_RX_QUEUES)];
/* Make sure we never check beyond our status buffer. */
if (WARN_ON_ONCE(channels_to_check > ARRAY_SIZE(status)))
diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
index 4b9280a3b673..d849f61b7519 100644
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -43,7 +43,7 @@
#include <net/sock.h>
#include <net/raw.h>
-#define TCPUDP_MIB_MAX max_t(u32, UDP_MIB_MAX, TCP_MIB_MAX)
+#define TCPUDP_MIB_MAX MAX_T(u32, UDP_MIB_MAX, TCP_MIB_MAX)
/*
* Report socket allocation statistics [mea@utu•fi]
diff --git a/net/ipv6/proc.c b/net/ipv6/proc.c
index d6306aa46bb1..e07c43bd5cb0 100644
--- a/net/ipv6/proc.c
+++ b/net/ipv6/proc.c
@@ -27,7 +27,7 @@
#include <net/ipv6.h>
#define MAX4(a, b, c, d) \
- max_t(u32, max_t(u32, a, b), max_t(u32, c, d))
+ MAX_T(u32, MAX_T(u32, a, b), MAX_T(u32, c, d))
#define SNMP_MIB_MAX MAX4(UDP_MIB_MAX, TCP_MIB_MAX, \
IPSTATS_MIB_MAX, ICMP_MIB_MAX)
--
2.47.3
next prev parent reply other threads:[~2025-10-02 20:51 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-02 20:47 [PATCH 00/19 5.15.y] Backport minmax.h updates from v6.17-rc7 Eliav Farber
2025-10-02 20:47 ` [PATCH 01/19 5.15.y] minmax: add in_range() macro Eliav Farber
2025-10-02 20:47 ` [PATCH 02/19 5.15.y] minmax: Introduce {min,max}_array() Eliav Farber
2025-10-02 20:47 ` [PATCH 03/19 5.15.y] minmax: deduplicate __unconst_integer_typeof() Eliav Farber
2025-10-02 20:47 ` [PATCH 04/19 5.15.y] minmax: fix indentation of __cmp_once() and __clamp_once() Eliav Farber
2025-10-02 20:47 ` [PATCH 05/19 5.15.y] minmax: avoid overly complicated constant expressions in VM code Eliav Farber
2025-10-02 20:47 ` [PATCH 06/19 5.15.y] minmax: make generic MIN() and MAX() macros available everywhere Eliav Farber
2025-10-02 20:47 ` Eliav Farber [this message]
2025-10-02 20:47 ` [PATCH 08/19 5.15.y] minmax: simplify and clarify min_t()/max_t() implementation Eliav Farber
2025-10-02 20:47 ` [PATCH 09/19 5.15.y] minmax: simplify min()/max()/clamp() implementation Eliav Farber
2025-10-02 20:47 ` [PATCH 10/19 5.15.y] minmax: don't use max() in situations that want a C constant expression Eliav Farber
2025-10-02 20:47 ` [PATCH 11/19 5.15.y] minmax: improve macro expansion and type checking Eliav Farber
2025-10-02 20:47 ` [PATCH 12/19 5.15.y] minmax: fix up min3() and max3() too Eliav Farber
2025-10-02 20:47 ` [PATCH 13/19 5.15.y] minmax.h: add whitespace around operators and after commas Eliav Farber
2025-10-02 20:47 ` [PATCH 14/19 5.15.y] minmax.h: update some comments Eliav Farber
2025-10-02 20:47 ` [PATCH 15/19 5.15.y] minmax.h: reduce the #define expansion of min(), max() and clamp() Eliav Farber
2025-10-02 20:47 ` [PATCH 16/19 5.15.y] minmax.h: use BUILD_BUG_ON_MSG() for the lo < hi test in clamp() Eliav Farber
2025-10-02 20:47 ` [PATCH 17/19 5.15.y] minmax.h: move all the clamp() definitions after the min/max() ones Eliav Farber
2025-10-02 20:47 ` [PATCH 18/19 5.15.y] minmax.h: simplify the variants of clamp() Eliav Farber
2025-10-02 20:47 ` [PATCH 19/19 5.15.y] minmax.h: remove some #defines that are only expanded once Eliav Farber
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