From: Linus Torvalds torvalds@linux-foundation.org

[ Upstream commit 1a251f52cfdc417c84411a056bc142cbd77baef4 ]

This just standardizes the use of MIN() and MAX() macros, with the very traditional semantics. The goal is to use these for C constant expressions and for top-level / static initializers, and so be able to simplify the min()/max() macros.

These macro names were used by various kernel code - they are very traditional, after all - and all such users have been fixed up, with a few different approaches:

- trivial duplicated macro definitions have been removed

Note that 'trivial' here means that it's obviously kernel code that already included all the major kernel headers, and thus gets the new generic MIN/MAX macros automatically.

- non-trivial duplicated macro definitions are guarded with #ifndef

This is the "yes, they define their own versions, but no, the include situation is not entirely obvious, and maybe they don't get the generic version automatically" case.

- strange use case #1

A couple of drivers decided that the way they want to describe their versioning is with

#define MAJ 1 #define MIN 2 #define DRV_VERSION __stringify(MAJ) "." __stringify(MIN)

which adds zero value and I just did my Alexander the Great impersonation, and rewrote that pointless Gordian knot as

#define DRV_VERSION "1.2"

instead.

- strange use case #2

A couple of drivers thought that it's a good idea to have a random 'MIN' or 'MAX' define for a value or index into a table, rather than the traditional macro that takes arguments.

These values were re-written as C enum's instead. The new function-line macros only expand when followed by an open parenthesis, and thus don't clash with enum use.

Happily, there weren't really all that many of these cases, and a lot of users already had the pattern of using '#ifndef' guarding (or in one case just using '#undef MIN') before defining their own private version that does the same thing. I left such cases alone.

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 --- v2: - Add missing #ifndef guards around MIN/MAX macro definitions to avoid redefinition errors in: * drivers/gpu/drm/amd/amdgpu/amdgpu.h * drivers/gpu/drm/amd/pm/swsmu/smu11/sienna_cichlid_ppt.c * drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0_0_ppt.c * drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0_7_ppt.c

arch/um/drivers/mconsole_user.c | 2 ++ drivers/edac/skx_common.h | 1 - drivers/gpu/drm/amd/amdgpu/amdgpu.h | 2 ++ .../drm/amd/display/modules/hdcp/hdcp_ddc.c | 2 ++ .../drm/amd/pm/powerplay/hwmgr/ppevvmath.h | 14 +++++++---- .../amd/pm/swsmu/smu11/sienna_cichlid_ppt.c | 2 ++ .../drm/amd/pm/swsmu/smu13/smu_v13_0_0_ppt.c | 3 +++ .../drm/amd/pm/swsmu/smu13/smu_v13_0_7_ppt.c | 3 +++ drivers/gpu/drm/radeon/evergreen_cs.c | 2 ++ drivers/hwmon/adt7475.c | 24 +++++++++---------- drivers/media/dvb-frontends/stv0367_priv.h | 3 +++ drivers/net/fjes/fjes_main.c | 4 +--- drivers/nfc/pn544/i2c.c | 2 -- drivers/platform/x86/sony-laptop.c | 1 - drivers/scsi/isci/init.c | 6 +---- .../pci/hive_isp_css_include/math_support.h | 5 ---- include/linux/minmax.h | 2 ++ kernel/trace/preemptirq_delay_test.c | 2 -- lib/btree.c | 1 - lib/decompress_unlzma.c | 2 ++ mm/zsmalloc.c | 1 - tools/testing/selftests/seccomp/seccomp_bpf.c | 2 ++ tools/testing/selftests/vm/mremap_test.c | 2 ++ 23 files changed, 51 insertions(+), 37 deletions(-)

diff --git a/arch/um/drivers/mconsole_user.c b/arch/um/drivers/mconsole_user.c index e24298a734be..a04cd13c6315 100644 --- a/arch/um/drivers/mconsole_user.c +++ b/arch/um/drivers/mconsole_user.c @@ -71,7 +71,9 @@ static struct mconsole_command *mconsole_parse(struct mc_request *req) return NULL; }

+#ifndef MIN #define MIN(a,b) ((a)<(b) ? (a):(b)) +#endif

#define STRINGX(x) #x #define STRING(x) STRINGX(x) diff --git a/drivers/edac/skx_common.h b/drivers/edac/skx_common.h index c0c174c101d2..c5e273bc2292 100644 --- a/drivers/edac/skx_common.h +++ b/drivers/edac/skx_common.h @@ -45,7 +45,6 @@ #define I10NM_NUM_CHANNELS MAX(I10NM_NUM_DDR_CHANNELS, I10NM_NUM_HBM_CHANNELS) #define I10NM_NUM_DIMMS MAX(I10NM_NUM_DDR_DIMMS, I10NM_NUM_HBM_DIMMS)

-#define MAX(a, b) ((a) > (b) ? (a) : (b)) #define NUM_IMC MAX(SKX_NUM_IMC, I10NM_NUM_IMC) #define NUM_CHANNELS MAX(SKX_NUM_CHANNELS, I10NM_NUM_CHANNELS) #define NUM_DIMMS MAX(SKX_NUM_DIMMS, I10NM_NUM_DIMMS) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h index af86402c70a9..dcb5de01a220 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h @@ -1258,7 +1258,9 @@ int emu_soc_asic_init(struct amdgpu_device *adev);

#define amdgpu_inc_vram_lost(adev) atomic_inc(&((adev)->vram_lost_counter));

+#ifndef MIN #define MIN(X, Y) ((X) < (Y) ? (X) : (Y)) +#endif

/* Common functions */ bool amdgpu_device_has_job_running(struct amdgpu_device *adev); diff --git a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_ddc.c b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_ddc.c index 1b2df97226a3..40286e8dd4e1 100644 --- a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_ddc.c +++ b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_ddc.c @@ -25,7 +25,9 @@

#include "hdcp.h"

+#ifndef MIN #define MIN(a, b) ((a) < (b) ? (a) : (b)) +#endif #define HDCP_I2C_ADDR 0x3a /* 0x74 >> 1*/ #define KSV_READ_SIZE 0xf /* 0x6803b - 0x6802c */ #define HDCP_MAX_AUX_TRANSACTION_SIZE 16 diff --git a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/ppevvmath.h b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/ppevvmath.h index dac29fe6cfc6..abbdb7731996 100644 --- a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/ppevvmath.h +++ b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/ppevvmath.h @@ -22,12 +22,18 @@ */ #include <asm/div64.h>

-#define SHIFT_AMOUNT 16 /* We multiply all original integers with 2^SHIFT_AMOUNT to get the fInt representation */ +enum ppevvmath_constants { + /* We multiply all original integers with 2^SHIFT_AMOUNT to get the fInt representation */ + SHIFT_AMOUNT = 16,

-#define PRECISION 5 /* Change this value to change the number of decimal places in the final output - 5 is a good default */ + /* Change this value to change the number of decimal places in the final output - 5 is a good default */ + PRECISION = 5,

-#define SHIFTED_2 (2 << SHIFT_AMOUNT) -#define MAX (1 << (SHIFT_AMOUNT - 1)) - 1 /* 32767 - Might change in the future */ + SHIFTED_2 = (2 << SHIFT_AMOUNT), + + /* 32767 - Might change in the future */ + MAX = (1 << (SHIFT_AMOUNT - 1)) - 1, +};

/* ------------------------------------------------------------------------------- * NEW TYPE - fINT diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu11/sienna_cichlid_ppt.c b/drivers/gpu/drm/amd/pm/swsmu/smu11/sienna_cichlid_ppt.c index cfd41d56e970..47371ec9963b 100644 --- a/drivers/gpu/drm/amd/pm/swsmu/smu11/sienna_cichlid_ppt.c +++ b/drivers/gpu/drm/amd/pm/swsmu/smu11/sienna_cichlid_ppt.c @@ -2081,7 +2081,9 @@ static int sienna_cichlid_display_disable_memory_clock_switch(struct smu_context return ret; }

+#ifndef MAX #define MAX(a, b) ((a) > (b) ? (a) : (b)) +#endif

static int sienna_cichlid_update_pcie_parameters(struct smu_context *smu, uint8_t pcie_gen_cap, diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0_0_ppt.c b/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0_0_ppt.c index af244def4801..ae8854b90f37 100644 --- a/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0_0_ppt.c +++ b/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0_0_ppt.c @@ -1255,7 +1255,10 @@ static int smu_v13_0_0_get_thermal_temperature_range(struct smu_context *smu, return 0; }

+#ifndef MAX #define MAX(a, b) ((a) > (b) ? (a) : (b)) +#endif + static ssize_t smu_v13_0_0_get_gpu_metrics(struct smu_context *smu, void **table) { diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0_7_ppt.c b/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0_7_ppt.c index 2d5cfe4651b4..f5e340c2c598 100644 --- a/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0_7_ppt.c +++ b/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0_7_ppt.c @@ -1263,7 +1263,10 @@ static int smu_v13_0_7_get_thermal_temperature_range(struct smu_context *smu, return 0; }

+#ifndef MAX #define MAX(a, b) ((a) > (b) ? (a) : (b)) +#endif + static ssize_t smu_v13_0_7_get_gpu_metrics(struct smu_context *smu, void **table) { diff --git a/drivers/gpu/drm/radeon/evergreen_cs.c b/drivers/gpu/drm/radeon/evergreen_cs.c index 820c2c3641d3..1311f10fad66 100644 --- a/drivers/gpu/drm/radeon/evergreen_cs.c +++ b/drivers/gpu/drm/radeon/evergreen_cs.c @@ -33,8 +33,10 @@ #include "evergreen_reg_safe.h" #include "cayman_reg_safe.h"

+#ifndef MIN #define MAX(a,b) (((a)>(b))?(a):(b)) #define MIN(a,b) (((a)<(b))?(a):(b)) +#endif

#define REG_SAFE_BM_SIZE ARRAY_SIZE(evergreen_reg_safe_bm)

diff --git a/drivers/hwmon/adt7475.c b/drivers/hwmon/adt7475.c index 3ac674427675..44eb31055256 100644 --- a/drivers/hwmon/adt7475.c +++ b/drivers/hwmon/adt7475.c @@ -23,23 +23,23 @@ #include <linux/util_macros.h>

/* Indexes for the sysfs hooks */ - -#define INPUT 0 -#define MIN 1 -#define MAX 2 -#define CONTROL 3 -#define OFFSET 3 -#define AUTOMIN 4 -#define THERM 5 -#define HYSTERSIS 6 - +enum adt_sysfs_id { + INPUT = 0, + MIN = 1, + MAX = 2, + CONTROL = 3, + OFFSET = 3, // Dup + AUTOMIN = 4, + THERM = 5, + HYSTERSIS = 6, /* * These are unique identifiers for the sysfs functions - unlike the * numbers above, these are not also indexes into an array */ + ALARM = 9, + FAULT = 10, +};

-#define ALARM 9 -#define FAULT 10

/* 7475 Common Registers */

diff --git a/drivers/media/dvb-frontends/stv0367_priv.h b/drivers/media/dvb-frontends/stv0367_priv.h index 617f605947b2..7f056d1cce82 100644 --- a/drivers/media/dvb-frontends/stv0367_priv.h +++ b/drivers/media/dvb-frontends/stv0367_priv.h @@ -25,8 +25,11 @@ #endif

/* MACRO definitions */ +#ifndef MIN #define MAX(X, Y) ((X) >= (Y) ? (X) : (Y)) #define MIN(X, Y) ((X) <= (Y) ? (X) : (Y)) +#endif + #define INRANGE(X, Y, Z) \ ((((X) <= (Y)) && ((Y) <= (Z))) || \ (((Z) <= (Y)) && ((Y) <= (X))) ? 1 : 0) diff --git a/drivers/net/fjes/fjes_main.c b/drivers/net/fjes/fjes_main.c index 1eff202f6a1f..e050910b08a2 100644 --- a/drivers/net/fjes/fjes_main.c +++ b/drivers/net/fjes/fjes_main.c @@ -14,9 +14,7 @@ #include "fjes.h" #include "fjes_trace.h"

-#define MAJ 1 -#define MIN 2 -#define DRV_VERSION __stringify(MAJ) "." __stringify(MIN) +#define DRV_VERSION "1.2" #define DRV_NAME "fjes" char fjes_driver_name[] = DRV_NAME; char fjes_driver_version[] = DRV_VERSION; diff --git a/drivers/nfc/pn544/i2c.c b/drivers/nfc/pn544/i2c.c index 9e754abcfa2a..50559d976f78 100644 --- a/drivers/nfc/pn544/i2c.c +++ b/drivers/nfc/pn544/i2c.c @@ -126,8 +126,6 @@ struct pn544_i2c_fw_secure_blob { #define PN544_FW_CMD_RESULT_COMMAND_REJECTED 0xE0 #define PN544_FW_CMD_RESULT_CHUNK_ERROR 0xE6

-#define MIN(X, Y) ((X) < (Y) ? (X) : (Y)) - #define PN544_FW_WRITE_BUFFER_MAX_LEN 0x9f7 #define PN544_FW_I2C_MAX_PAYLOAD PN544_HCI_I2C_LLC_MAX_SIZE #define PN544_FW_I2C_WRITE_FRAME_HEADER_LEN 8 diff --git a/drivers/platform/x86/sony-laptop.c b/drivers/platform/x86/sony-laptop.c index 5ff5aaf92b56..b80007676c2d 100644 --- a/drivers/platform/x86/sony-laptop.c +++ b/drivers/platform/x86/sony-laptop.c @@ -757,7 +757,6 @@ static union acpi_object *__call_snc_method(acpi_handle handle, char *method, return result; }

-#define MIN(a, b) (a > b ? b : a) static int sony_nc_buffer_call(acpi_handle handle, char *name, u64 *value, void *buffer, size_t buflen) { diff --git a/drivers/scsi/isci/init.c b/drivers/scsi/isci/init.c index e294d5d961eb..012cd2dade86 100644 --- a/drivers/scsi/isci/init.c +++ b/drivers/scsi/isci/init.c @@ -65,11 +65,7 @@ #include "task.h" #include "probe_roms.h"

-#define MAJ 1 -#define MIN 2 -#define BUILD 0 -#define DRV_VERSION __stringify(MAJ) "." __stringify(MIN) "." \ - __stringify(BUILD) +#define DRV_VERSION "1.2.0"

MODULE_VERSION(DRV_VERSION);

diff --git a/drivers/staging/media/atomisp/pci/hive_isp_css_include/math_support.h b/drivers/staging/media/atomisp/pci/hive_isp_css_include/math_support.h index a444ec14ff9d..1c17a87a8572 100644 --- a/drivers/staging/media/atomisp/pci/hive_isp_css_include/math_support.h +++ b/drivers/staging/media/atomisp/pci/hive_isp_css_include/math_support.h @@ -31,11 +31,6 @@ /* A => B */ #define IMPLIES(a, b) (!(a) || (b))

-/* for preprocessor and array sizing use MIN and MAX - otherwise use min and max */ -#define MAX(a, b) (((a) > (b)) ? (a) : (b)) -#define MIN(a, b) (((a) < (b)) ? (a) : (b)) - #define ROUND_DIV(a, b) (((b) != 0) ? ((a) + ((b) >> 1)) / (b) : 0) #define CEIL_DIV(a, b) (((b) != 0) ? ((a) + (b) - 1) / (b) : 0) #define CEIL_MUL(a, b) (CEIL_DIV(a, b) * (b)) diff --git a/include/linux/minmax.h b/include/linux/minmax.h index 9c2848abc804..fc384714da45 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -277,6 +277,8 @@ static inline bool in_range32(u32 val, u32 start, u32 len) * Use these carefully: no type checking, and uses the arguments * multiple times. Use for obvious constants only. */ +#define MIN(a,b) __cmp(min,a,b) +#define MAX(a,b) __cmp(max,a,b) #define MIN_T(type,a,b) __cmp(min,(type)(a),(type)(b)) #define MAX_T(type,a,b) __cmp(max,(type)(a),(type)(b))

diff --git a/kernel/trace/preemptirq_delay_test.c b/kernel/trace/preemptirq_delay_test.c index 8af92dbe98f0..acb0c971a408 100644 --- a/kernel/trace/preemptirq_delay_test.c +++ b/kernel/trace/preemptirq_delay_test.c @@ -34,8 +34,6 @@ MODULE_PARM_DESC(cpu_affinity, "Cpu num test is running on");

static struct completion done;

-#define MIN(x, y) ((x) < (y) ? (x) : (y)) - static void busy_wait(ulong time) { u64 start, end; diff --git a/lib/btree.c b/lib/btree.c index a82100c73b55..8407ff7dca1a 100644 --- a/lib/btree.c +++ b/lib/btree.c @@ -43,7 +43,6 @@ #include <linux/slab.h> #include <linux/module.h>

-#define MAX(a, b) ((a) > (b) ? (a) : (b)) #define NODESIZE MAX(L1_CACHE_BYTES, 128)

struct btree_geo { diff --git a/lib/decompress_unlzma.c b/lib/decompress_unlzma.c index 20a858031f12..9d34d35908da 100644 --- a/lib/decompress_unlzma.c +++ b/lib/decompress_unlzma.c @@ -37,7 +37,9 @@

#include <linux/decompress/mm.h>

+#ifndef MIN #define MIN(a, b) (((a) < (b)) ? (a) : (b)) +#endif

static long long INIT read_int(unsigned char *ptr, int size) { diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index af130e2dcea2..aede005d1adc 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -123,7 +123,6 @@ #define ISOLATED_BITS 3 #define MAGIC_VAL_BITS 8

-#define MAX(a, b) ((a) >= (b) ? (a) : (b)) /* ZS_MIN_ALLOC_SIZE must be multiple of ZS_ALIGN */ #define ZS_MIN_ALLOC_SIZE \ MAX(32, (ZS_MAX_PAGES_PER_ZSPAGE << PAGE_SHIFT >> OBJ_INDEX_BITS)) diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index b300e87404d8..b054bfef0f4f 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -60,7 +60,9 @@ #define SKIP(s, ...) XFAIL(s, ##__VA_ARGS__) #endif

+#ifndef MIN #define MIN(X, Y) ((X) < (Y) ? (X) : (Y)) +#endif

#ifndef PR_SET_PTRACER # define PR_SET_PTRACER 0x59616d61 diff --git a/tools/testing/selftests/vm/mremap_test.c b/tools/testing/selftests/vm/mremap_test.c index 9496346973d4..7f674160f01e 100644 --- a/tools/testing/selftests/vm/mremap_test.c +++ b/tools/testing/selftests/vm/mremap_test.c @@ -22,7 +22,9 @@ #define VALIDATION_DEFAULT_THRESHOLD 4 /* 4MB */ #define VALIDATION_NO_THRESHOLD 0 /* Verify the entire region */

+#ifndef MIN #define MIN(X, Y) ((X) < (Y) ? (X) : (Y)) +#endif

struct config { unsigned long long src_alignment;

From: Linus Torvalds torvalds@linux-foundation.org

[ Upstream commit dc1c8034e31b14a2e5e212104ec508aec44ce1b9 ]

Now that we no longer have any C constant expression contexts (ie array size declarations or static initializers) that use min() or max(), we can simpify the implementation by not having to worry about the result staying as a C constant expression.

So now we can unconditionally just use temporary variables of the right type, and get rid of the excessive expansion that used to come from the use of

__builtin_choose_expr(__is_constexpr(...), ..

to pick the specialized code for constant expressions.

Another expansion simplification is to pass the temporary variables (in addition to the original expression) to our __types_ok() macro. That may superficially look like it complicates the macro, but when we only want the type of the expression, expanding the temporary variable names is much simpler and smaller than expanding the potentially complicated original expression.

As a result, on my machine, doing a

$ time make drivers/staging/media/atomisp/pci/isp/kernels/ynr/ynr_1.0/ia_css_ynr.host.i

goes from

real 0m16.621s user 0m15.360s sys 0m1.221s

to

real 0m2.532s user 0m2.091s sys 0m0.452s

because the token expansion goes down dramatically.

In particular, the longest line expansion (which was line 71 of that 'ia_css_ynr.host.c' file) shrinks from 23,338kB (yes, 23MB for one single line) to "just" 1,444kB (now "only" 1.4MB).

And yes, that line is still the line from hell, because it's doing multiple levels of "min()/max()" expansion thanks to some of them being hidden inside the uDIGIT_FITTING() macro.

Lorenzo has a nice cleanup patch that makes that driver use inline functions instead of macros for sDIGIT_FITTING() and uDIGIT_FITTING(), which will fix that line once and for all, but the 16-fold reduction in this case does show why we need to simplify these helpers.

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 --- include/linux/minmax.h | 43 ++++++++++++++++++++---------------------- 1 file changed, 20 insertions(+), 23 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h index fc384714da45..e3e4353df983 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -35,10 +35,10 @@ #define __is_noneg_int(x) \ (__builtin_choose_expr(__is_constexpr(x) && __is_signed(x), x, -1) >= 0)

-#define __types_ok(x, y) \ - (__is_signed(x) == __is_signed(y) || \ - __is_signed((x) + 0) == __is_signed((y) + 0) || \ - __is_noneg_int(x) || __is_noneg_int(y)) +#define __types_ok(x, y, ux, uy) \ + (__is_signed(ux) == __is_signed(uy) || \ + __is_signed((ux) + 0) == __is_signed((uy) + 0) || \ + __is_noneg_int(x) || __is_noneg_int(y))

#define __cmp_op_min < #define __cmp_op_max > @@ -51,34 +51,31 @@ #define __cmp_once(op, type, x, y) \ __cmp_once_unique(op, type, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_))

-#define __careful_cmp_once(op, x, y) ({ \ - static_assert(__types_ok(x, y), \ +#define __careful_cmp_once(op, x, y, ux, uy) ({ \ + __auto_type ux = (x); __auto_type uy = (y); \ + static_assert(__types_ok(x, y, ux, uy), \ #op "(" #x ", " #y ") signedness error, fix types or consider u" #op "() before " #op "_t()"); \ - __cmp_once(op, __auto_type, x, y); }) + __cmp(op, ux, uy); })

-#define __careful_cmp(op, x, y) \ - __builtin_choose_expr(__is_constexpr((x) - (y)), \ - __cmp(op, x, y), __careful_cmp_once(op, x, y)) +#define __careful_cmp(op, x, y) \ + __careful_cmp_once(op, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_))

#define __clamp(val, lo, hi) \ ((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val)))

-#define __clamp_once(val, lo, hi, unique_val, unique_lo, unique_hi) ({ \ - typeof(val) unique_val = (val); \ - typeof(lo) unique_lo = (lo); \ - typeof(hi) unique_hi = (hi); \ +#define __clamp_once(val, lo, hi, uval, ulo, uhi) ({ \ + __auto_type uval = (val); \ + __auto_type ulo = (lo); \ + __auto_type uhi = (hi); \ static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), \ (lo) <= (hi), true), \ "clamp() low limit " #lo " greater than high limit " #hi); \ - static_assert(__types_ok(val, lo), "clamp() 'lo' signedness error"); \ - static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error"); \ - __clamp(unique_val, unique_lo, unique_hi); }) - -#define __careful_clamp(val, lo, hi) ({ \ - __builtin_choose_expr(__is_constexpr((val) - (lo) + (hi)), \ - __clamp(val, lo, hi), \ - __clamp_once(val, lo, hi, __UNIQUE_ID(__val), \ - __UNIQUE_ID(__lo), __UNIQUE_ID(__hi))); }) + static_assert(__types_ok(uval, lo, uval, ulo), "clamp() 'lo' signedness error"); \ + static_assert(__types_ok(uval, hi, uval, uhi), "clamp() 'hi' signedness error"); \ + __clamp(uval, ulo, uhi); }) + +#define __careful_clamp(val, lo, hi) \ + __clamp_once(val, lo, hi, __UNIQUE_ID(v_), __UNIQUE_ID(l_), __UNIQUE_ID(h_))

/** * min - return minimum of two values of the same or compatible types

From: Linus Torvalds torvalds@linux-foundation.org

[ Upstream commit 22f5468731491e53356ba7c028f0fdea20b18e2c ]

This clarifies the rules for min()/max()/clamp() type checking and makes them a much more efficient macro expansion.

In particular, we now look at the type and range of the inputs to see whether they work together, generating a mask of acceptable comparisons, and then just verifying that the inputs have a shared case:

- an expression with a signed type can be used for (1) signed comparisons (2) unsigned comparisons if it is statically known to have a non-negative value

- an expression with an unsigned type can be used for (3) unsigned comparison (4) signed comparisons if the type is smaller than 'int' and thus the C integer promotion rules will make it signed anyway

Here rule (1) and (3) are obvious, and rule (2) is important in order to allow obvious trivial constants to be used together with unsigned values.

Rule (4) is not necessarily a good idea, but matches what we used to do, and we have extant cases of this situation in the kernel. Notably with bcachefs having an expression like

min(bch2_bucket_sectors_dirty(a), ca->mi.bucket_size)

where bch2_bucket_sectors_dirty() returns an 's64', and 'ca->mi.bucket_size' is of type 'u16'.

Technically that bcachefs comparison is clearly sensible on a C type level, because the 'u16' will go through the normal C integer promotion, and become 'int', and then we're comparing two signed values and everything looks sane.

However, it's not entirely clear that a 'min(s64,u16)' operation makes a lot of conceptual sense, and it's possible that we will remove rule (4). After all, the _reason_ we have these complicated type checks is exactly that the C type promotion rules are not very intuitive.

But at least for now the rule is in place for backwards compatibility.

Also note that rule (2) existed before, but is hugely relaxed by this commit. It used to be true only for the simplest compile-time non-negative integer constants. The new macro model will allow cases where the compiler can trivially see that an expression is non-negative even if it isn't necessarily a constant.

For example, the amdgpu driver does

min_t(size_t, sizeof(fru_info->serial), pia[addr] & 0x3F));

because our old 'min()' macro would see that 'pia[addr] & 0x3F' is of type 'int' and clearly not a C constant expression, so doing a 'min()' with a 'size_t' is a signedness violation.

Our new 'min()' macro still sees that 'pia[addr] & 0x3F' is of type 'int', but is smart enough to also see that it is clearly non-negative, and thus would allow that case without any complaints.

Cc: Arnd Bergmann arnd@kernel.org 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 --- include/linux/compiler.h | 9 +++++ include/linux/minmax.h | 74 ++++++++++++++++++++++++++++++++-------- 2 files changed, 68 insertions(+), 15 deletions(-)

diff --git a/include/linux/compiler.h b/include/linux/compiler.h index f6ea15821cea..a6a7be83fae6 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -244,6 +244,15 @@ static inline void *offset_to_ptr(const int *off) */ #define is_signed_type(type) (((type)(-1)) < (__force type)1)

+/* + * Useful shorthand for "is this condition known at compile-time?" + * + * Note that the condition may involve non-constant values, + * but the compiler may know enough about the details of the + * values to determine that the condition is statically true. + */ +#define statically_true(x) (__builtin_constant_p(x) && (x)) + /* * This is needed in functions which generate the stack canary, see * arch/x86/kernel/smpboot.c::start_secondary() for an example. diff --git a/include/linux/minmax.h b/include/linux/minmax.h index e3e4353df983..41da6f85a407 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -26,19 +26,63 @@ #define __typecheck(x, y) \ (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))

-/* is_signed_type() isn't a constexpr for pointer types */ -#define __is_signed(x) \ - __builtin_choose_expr(__is_constexpr(is_signed_type(typeof(x))), \ - is_signed_type(typeof(x)), 0) +/* + * __sign_use for integer expressions: + * bit #0 set if ok for unsigned comparisons + * bit #1 set if ok for signed comparisons + * + * In particular, statically non-negative signed integer + * expressions are ok for both. + * + * NOTE! Unsigned types smaller than 'int' are implicitly + * converted to 'int' in expressions, and are accepted for + * signed conversions for now. This is debatable. + * + * Note that 'x' is the original expression, and 'ux' is + * the unique variable that contains the value. + * + * We use 'ux' for pure type checking, and 'x' for when + * we need to look at the value (but without evaluating + * it for side effects! Careful to only ever evaluate it + * with sizeof() or __builtin_constant_p() etc). + * + * Pointers end up being checked by the normal C type + * rules at the actual comparison, and these expressions + * only need to be careful to not cause warnings for + * pointer use. + */ +#define __signed_type_use(x,ux) (2+__is_nonneg(x,ux)) +#define __unsigned_type_use(x,ux) (1+2*(sizeof(ux)<4)) +#define __sign_use(x,ux) (is_signed_type(typeof(ux))? \ + __signed_type_use(x,ux):__unsigned_type_use(x,ux)) + +/* + * To avoid warnings about casting pointers to integers + * of different sizes, we need that special sign type. + * + * On 64-bit we can just always use 'long', since any + * integer or pointer type can just be cast to that. + * + * This does not work for 128-bit signed integers since + * the cast would truncate them, but we do not use s128 + * types in the kernel (we do use 'u128', but they will + * be handled by the !is_signed_type() case). + * + * NOTE! The cast is there only to avoid any warnings + * from when values that aren't signed integer types. + */ +#ifdef CONFIG_64BIT + #define __signed_type(ux) long +#else + #define __signed_type(ux) typeof(__builtin_choose_expr(sizeof(ux)>4,1LL,1L)) +#endif +#define __is_nonneg(x,ux) statically_true((__signed_type(ux))(x)>=0)

-/* True for a non-negative signed int constant */ -#define __is_noneg_int(x) \ - (__builtin_choose_expr(__is_constexpr(x) && __is_signed(x), x, -1) >= 0) +#define __types_ok(x,y,ux,uy) \ + (__sign_use(x,ux) & __sign_use(y,uy))

-#define __types_ok(x, y, ux, uy) \ - (__is_signed(ux) == __is_signed(uy) || \ - __is_signed((ux) + 0) == __is_signed((uy) + 0) || \ - __is_noneg_int(x) || __is_noneg_int(y)) +#define __types_ok3(x,y,z,ux,uy,uz) \ + (__sign_use(x,ux) & __sign_use(y,uy) & __sign_use(z,uz))

#define __cmp_op_min < #define __cmp_op_max > @@ -53,8 +97,8 @@

#define __careful_cmp_once(op, x, y, ux, uy) ({ \ __auto_type ux = (x); __auto_type uy = (y); \ - static_assert(__types_ok(x, y, ux, uy), \ - #op "(" #x ", " #y ") signedness error, fix types or consider u" #op "() before " #op "_t()"); \ + BUILD_BUG_ON_MSG(!__types_ok(x,y,ux,uy), \ + #op"("#x", "#y") signedness error"); \ __cmp(op, ux, uy); })

#define __careful_cmp(op, x, y) \ @@ -70,8 +114,8 @@ static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), \ (lo) <= (hi), true), \ "clamp() low limit " #lo " greater than high limit " #hi); \ - static_assert(__types_ok(uval, lo, uval, ulo), "clamp() 'lo' signedness error"); \ - static_assert(__types_ok(uval, hi, uval, uhi), "clamp() 'hi' signedness error"); \ + BUILD_BUG_ON_MSG(!__types_ok3(val,lo,hi,uval,ulo,uhi), \ + "clamp("#val", "#lo", "#hi") signedness error"); \ __clamp(uval, ulo, uhi); })

#define __careful_clamp(val, lo, hi) \

From: David Laight David.Laight@ACULAB.COM

[ Upstream commit 71ee9b16251ea4bf7c1fe222517c82bdb3220acc ]

Patch series "minmax.h: Cleanups and minor optimisations".

Some tidyups and minor changes to minmax.h.

This patch (of 7):

Link: https://lkml.kernel.org/r/c50365d214e04f9ba256d417c8bebbc0@AcuMS.aculab.com Link: https://lkml.kernel.org/r/f04b2e1310244f62826267346fde0553@AcuMS.aculab.com Signed-off-by: David Laight david.laight@aculab.com Cc: Andy Shevchenko andriy.shevchenko@linux.intel.com Cc: Arnd Bergmann arnd@kernel.org Cc: Christoph Hellwig hch@infradead.org Cc: Dan Carpenter dan.carpenter@linaro.org Cc: Jason A. Donenfeld Jason@zx2c4.com Cc: Jens Axboe axboe@kernel.dk Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Cc: Mateusz Guzik mjguzik@gmail.com Cc: Matthew Wilcox willy@infradead.org Cc: Pedro Falcato pedro.falcato@gmail.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Eliav Farber farbere@amazon.com --- include/linux/minmax.h | 34 +++++++++++++++++----------------- 1 file changed, 17 insertions(+), 17 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h index 98008dd92153..51b0d988e322 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -51,10 +51,10 @@ * only need to be careful to not cause warnings for * pointer use. */ -#define __signed_type_use(x,ux) (2+__is_nonneg(x,ux)) -#define __unsigned_type_use(x,ux) (1+2*(sizeof(ux)<4)) -#define __sign_use(x,ux) (is_signed_type(typeof(ux))? \ - __signed_type_use(x,ux):__unsigned_type_use(x,ux)) +#define __signed_type_use(x, ux) (2 + __is_nonneg(x, ux)) +#define __unsigned_type_use(x, ux) (1 + 2 * (sizeof(ux) < 4)) +#define __sign_use(x, ux) (is_signed_type(typeof(ux)) ? \ + __signed_type_use(x, ux) : __unsigned_type_use(x, ux))

/* * To avoid warnings about casting pointers to integers @@ -74,15 +74,15 @@ #ifdef CONFIG_64BIT #define __signed_type(ux) long #else - #define __signed_type(ux) typeof(__builtin_choose_expr(sizeof(ux)>4,1LL,1L)) + #define __signed_type(ux) typeof(__builtin_choose_expr(sizeof(ux) > 4, 1LL, 1L)) #endif -#define __is_nonneg(x,ux) statically_true((__signed_type(ux))(x)>=0) +#define __is_nonneg(x, ux) statically_true((__signed_type(ux))(x) >= 0)

-#define __types_ok(x,y,ux,uy) \ - (__sign_use(x,ux) & __sign_use(y,uy)) +#define __types_ok(x, y, ux, uy) \ + (__sign_use(x, ux) & __sign_use(y, uy))

-#define __types_ok3(x,y,z,ux,uy,uz) \ - (__sign_use(x,ux) & __sign_use(y,uy) & __sign_use(z,uz)) +#define __types_ok3(x, y, z, ux, uy, uz) \ + (__sign_use(x, ux) & __sign_use(y, uy) & __sign_use(z, uz))

#define __cmp_op_min < #define __cmp_op_max > @@ -97,7 +97,7 @@

#define __careful_cmp_once(op, x, y, ux, uy) ({ \ __auto_type ux = (x); __auto_type uy = (y); \ - BUILD_BUG_ON_MSG(!__types_ok(x,y,ux,uy), \ + BUILD_BUG_ON_MSG(!__types_ok(x, y, ux, uy), \ #op"("#x", "#y") signedness error"); \ __cmp(op, ux, uy); })

@@ -114,7 +114,7 @@ static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), \ (lo) <= (hi), true), \ "clamp() low limit " #lo " greater than high limit " #hi); \ - BUILD_BUG_ON_MSG(!__types_ok3(val,lo,hi,uval,ulo,uhi), \ + BUILD_BUG_ON_MSG(!__types_ok3(val, lo, hi, uval, ulo, uhi), \ "clamp("#val", "#lo", "#hi") signedness error"); \ __clamp(uval, ulo, uhi); })

@@ -154,7 +154,7 @@

#define __careful_op3(op, x, y, z, ux, uy, uz) ({ \ __auto_type ux = (x); __auto_type uy = (y);__auto_type uz = (z);\ - BUILD_BUG_ON_MSG(!__types_ok3(x,y,z,ux,uy,uz), \ + BUILD_BUG_ON_MSG(!__types_ok3(x, y, z, ux, uy, uz), \ #op"3("#x", "#y", "#z") signedness error"); \ __cmp(op, ux, __cmp(op, uy, uz)); })

@@ -326,9 +326,9 @@ static inline bool in_range32(u32 val, u32 start, u32 len) * Use these carefully: no type checking, and uses the arguments * multiple times. Use for obvious constants only. */ -#define MIN(a,b) __cmp(min,a,b) -#define MAX(a,b) __cmp(max,a,b) -#define MIN_T(type,a,b) __cmp(min,(type)(a),(type)(b)) -#define MAX_T(type,a,b) __cmp(max,(type)(a),(type)(b)) +#define MIN(a, b) __cmp(min, a, b) +#define MAX(a, b) __cmp(max, a, b) +#define MIN_T(type, a, b) __cmp(min, (type)(a), (type)(b)) +#define MAX_T(type, a, b) __cmp(max, (type)(a), (type)(b))

#endif /* _LINUX_MINMAX_H */

From: David Laight David.Laight@ACULAB.COM

[ Upstream commit b280bb27a9f7c91ddab730e1ad91a9c18a051f41 ]

Since the test for signed values being non-negative only relies on __builtion_constant_p() (not is_constexpr()) it can use the 'ux' variable instead of the caller supplied expression. This means that the #define parameters are only expanded twice. Once in the code and once quoted in the error message.

Link: https://lkml.kernel.org/r/051afc171806425da991908ed8688a98@AcuMS.aculab.com Signed-off-by: David Laight david.laight@aculab.com Cc: Andy Shevchenko andriy.shevchenko@linux.intel.com Cc: Arnd Bergmann arnd@kernel.org Cc: Christoph Hellwig hch@infradead.org Cc: Dan Carpenter dan.carpenter@linaro.org Cc: Jason A. Donenfeld Jason@zx2c4.com Cc: Jens Axboe axboe@kernel.dk Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Cc: Mateusz Guzik mjguzik@gmail.com Cc: Matthew Wilcox willy@infradead.org Cc: Pedro Falcato pedro.falcato@gmail.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Eliav Farber farbere@amazon.com --- include/linux/minmax.h | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h index 24e4b372649a..6f7ea669d305 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -46,10 +46,10 @@ * comparison, and these expressions only need to be careful to not cause * warnings for pointer use. */ -#define __signed_type_use(x, ux) (2 + __is_nonneg(x, ux)) -#define __unsigned_type_use(x, ux) (1 + 2 * (sizeof(ux) < 4)) -#define __sign_use(x, ux) (is_signed_type(typeof(ux)) ? \ - __signed_type_use(x, ux) : __unsigned_type_use(x, ux)) +#define __signed_type_use(ux) (2 + __is_nonneg(ux)) +#define __unsigned_type_use(ux) (1 + 2 * (sizeof(ux) < 4)) +#define __sign_use(ux) (is_signed_type(typeof(ux)) ? \ + __signed_type_use(ux) : __unsigned_type_use(ux))

/* * Check whether a signed value is always non-negative. @@ -71,13 +71,13 @@ #else #define __signed_type(ux) typeof(__builtin_choose_expr(sizeof(ux) > 4, 1LL, 1L)) #endif -#define __is_nonneg(x, ux) statically_true((__signed_type(ux))(x) >= 0) +#define __is_nonneg(ux) statically_true((__signed_type(ux))(ux) >= 0)

-#define __types_ok(x, y, ux, uy) \ - (__sign_use(x, ux) & __sign_use(y, uy)) +#define __types_ok(ux, uy) \ + (__sign_use(ux) & __sign_use(uy))

-#define __types_ok3(x, y, z, ux, uy, uz) \ - (__sign_use(x, ux) & __sign_use(y, uy) & __sign_use(z, uz)) +#define __types_ok3(ux, uy, uz) \ + (__sign_use(ux) & __sign_use(uy) & __sign_use(uz))

#define __cmp_op_min < #define __cmp_op_max > @@ -92,7 +92,7 @@

#define __careful_cmp_once(op, x, y, ux, uy) ({ \ __auto_type ux = (x); __auto_type uy = (y); \ - BUILD_BUG_ON_MSG(!__types_ok(x, y, ux, uy), \ + BUILD_BUG_ON_MSG(!__types_ok(ux, uy), \ #op"("#x", "#y") signedness error"); \ __cmp(op, ux, uy); })

@@ -109,7 +109,7 @@ static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), \ (lo) <= (hi), true), \ "clamp() low limit " #lo " greater than high limit " #hi); \ - BUILD_BUG_ON_MSG(!__types_ok3(val, lo, hi, uval, ulo, uhi), \ + BUILD_BUG_ON_MSG(!__types_ok3(uval, ulo, uhi), \ "clamp("#val", "#lo", "#hi") signedness error"); \ __clamp(uval, ulo, uhi); })

@@ -149,7 +149,7 @@

#define __careful_op3(op, x, y, z, ux, uy, uz) ({ \ __auto_type ux = (x); __auto_type uy = (y);__auto_type uz = (z);\ - BUILD_BUG_ON_MSG(!__types_ok3(x, y, z, ux, uy, uz), \ + BUILD_BUG_ON_MSG(!__types_ok3(ux, uy, uz), \ #op"3("#x", "#y", "#z") signedness error"); \ __cmp(op, ux, __cmp(op, uy, uz)); })

From: David Laight David.Laight@ACULAB.COM

[ Upstream commit c3939872ee4a6b8bdcd0e813c66823b31e6e26f7 ]

At some point the definitions for clamp() got added in the middle of the ones for min() and max(). Re-order the definitions so they are more sensibly grouped.

Link: https://lkml.kernel.org/r/8bb285818e4846469121c8abc3dfb6e2@AcuMS.aculab.com Signed-off-by: David Laight david.laight@aculab.com Cc: Andy Shevchenko andriy.shevchenko@linux.intel.com Cc: Arnd Bergmann arnd@kernel.org Cc: Christoph Hellwig hch@infradead.org Cc: Dan Carpenter dan.carpenter@linaro.org Cc: Jason A. Donenfeld Jason@zx2c4.com Cc: Jens Axboe axboe@kernel.dk Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Cc: Mateusz Guzik mjguzik@gmail.com Cc: Matthew Wilcox willy@infradead.org Cc: Pedro Falcato pedro.falcato@gmail.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Eliav Farber farbere@amazon.com --- include/linux/minmax.h | 109 +++++++++++++++++++---------------------- 1 file changed, 51 insertions(+), 58 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h index 91aa1b90c1bb..75fb7a6ad4c6 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -99,22 +99,6 @@ #define __careful_cmp(op, x, y) \ __careful_cmp_once(op, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_))

-#define __clamp(val, lo, hi) \ - ((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val))) - -#define __clamp_once(val, lo, hi, uval, ulo, uhi) ({ \ - __auto_type uval = (val); \ - __auto_type ulo = (lo); \ - __auto_type uhi = (hi); \ - BUILD_BUG_ON_MSG(statically_true(ulo > uhi), \ - "clamp() low limit " #lo " greater than high limit " #hi); \ - BUILD_BUG_ON_MSG(!__types_ok3(uval, ulo, uhi), \ - "clamp("#val", "#lo", "#hi") signedness error"); \ - __clamp(uval, ulo, uhi); }) - -#define __careful_clamp(val, lo, hi) \ - __clamp_once(val, lo, hi, __UNIQUE_ID(v_), __UNIQUE_ID(l_), __UNIQUE_ID(h_)) - /** * min - return minimum of two values of the same or compatible types * @x: first value @@ -170,6 +154,22 @@ #define max3(x, y, z) \ __careful_op3(max, x, y, z, __UNIQUE_ID(x_), __UNIQUE_ID(y_), __UNIQUE_ID(z_))

+/** + * min_t - return minimum of two values, using the specified type + * @type: data type to use + * @x: first value + * @y: second value + */ +#define min_t(type, x, y) __cmp_once(min, type, x, y) + +/** + * max_t - return maximum of two values, using the specified type + * @type: data type to use + * @x: first value + * @y: second value + */ +#define max_t(type, x, y) __cmp_once(max, type, x, y) + /** * min_not_zero - return the minimum that is _not_ zero, unless both are zero * @x: value1 @@ -180,6 +180,22 @@ typeof(y) __y = (y); \ __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })

+#define __clamp(val, lo, hi) \ + ((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val))) + +#define __clamp_once(val, lo, hi, uval, ulo, uhi) ({ \ + __auto_type uval = (val); \ + __auto_type ulo = (lo); \ + __auto_type uhi = (hi); \ + BUILD_BUG_ON_MSG(statically_true(ulo > uhi), \ + "clamp() low limit " #lo " greater than high limit " #hi); \ + BUILD_BUG_ON_MSG(!__types_ok3(uval, ulo, uhi), \ + "clamp("#val", "#lo", "#hi") signedness error"); \ + __clamp(uval, ulo, uhi); }) + +#define __careful_clamp(val, lo, hi) \ + __clamp_once(val, lo, hi, __UNIQUE_ID(v_), __UNIQUE_ID(l_), __UNIQUE_ID(h_)) + /** * clamp - return a value clamped to a given range with strict typechecking * @val: current value @@ -191,28 +207,30 @@ */ #define clamp(val, lo, hi) __careful_clamp(val, lo, hi)

-/* - * ..and if you can't take the strict - * types, you can specify one yourself. - * - * Or not use min/max/clamp at all, of course. - */ - /** - * min_t - return minimum of two values, using the specified type - * @type: data type to use - * @x: first value - * @y: second value + * clamp_t - return a value clamped to a given range using a given type + * @type: the type of variable to use + * @val: current value + * @lo: minimum allowable value + * @hi: maximum allowable value + * + * This macro does no typechecking and uses temporary variables of type + * @type to make all the comparisons. */ -#define min_t(type, x, y) __cmp_once(min, type, x, y) +#define clamp_t(type, val, lo, hi) __careful_clamp((type)(val), (type)(lo), (type)(hi))

/** - * max_t - return maximum of two values, using the specified type - * @type: data type to use - * @x: first value - * @y: second value + * clamp_val - return a value clamped to a given range using val's type + * @val: current value + * @lo: minimum allowable value + * @hi: maximum allowable value + * + * This macro does no typechecking and uses temporary variables of whatever + * type the input argument @val is. This is useful when @val is an unsigned + * type and @lo and @hi are literals that will otherwise be assigned a signed + * integer type. */ -#define max_t(type, x, y) __cmp_once(max, type, x, y) +#define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)

/* * Do not check the array parameter using __must_be_array(). @@ -257,31 +275,6 @@ */ #define max_array(array, len) __minmax_array(max, array, len)

-/** - * clamp_t - return a value clamped to a given range using a given type - * @type: the type of variable to use - * @val: current value - * @lo: minimum allowable value - * @hi: maximum allowable value - * - * This macro does no typechecking and uses temporary variables of type - * @type to make all the comparisons. - */ -#define clamp_t(type, val, lo, hi) __careful_clamp((type)(val), (type)(lo), (type)(hi)) - -/** - * clamp_val - return a value clamped to a given range using val's type - * @val: current value - * @lo: minimum allowable value - * @hi: maximum allowable value - * - * This macro does no typechecking and uses temporary variables of whatever - * type the input argument @val is. This is useful when @val is an unsigned - * type and @lo and @hi are literals that will otherwise be assigned a signed - * integer type. - */ -#define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi) - static inline bool in_range64(u64 val, u64 start, u64 len) { return (val - start) < len;

From: David Laight David.Laight@ACULAB.COM

[ Upstream commit 2b97aaf74ed534fb838d09867d09a3ca5d795208 ]

The bodies of __signed_type_use() and __unsigned_type_use() are much the same size as their names - so put the bodies in the only line that expands them.

Similarly __signed_type() is defined separately for 64bit and then used exactly once just below.

Change the test for __signed_type from CONFIG_64BIT to one based on gcc defined macros so that the code is valid if it gets used outside of a kernel build.

Link: https://lkml.kernel.org/r/9386d1ebb8974fbabbed2635160c3975@AcuMS.aculab.com Signed-off-by: David Laight david.laight@aculab.com Cc: Andy Shevchenko andriy.shevchenko@linux.intel.com Cc: Arnd Bergmann arnd@kernel.org Cc: Christoph Hellwig hch@infradead.org Cc: Dan Carpenter dan.carpenter@linaro.org Cc: Jason A. Donenfeld Jason@zx2c4.com Cc: Jens Axboe axboe@kernel.dk Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Cc: Mateusz Guzik mjguzik@gmail.com Cc: Matthew Wilcox willy@infradead.org Cc: Pedro Falcato pedro.falcato@gmail.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Eliav Farber farbere@amazon.com --- include/linux/minmax.h | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h index 2bbdd5b5e07e..eaaf5c008e4d 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -46,10 +46,8 @@ * comparison, and these expressions only need to be careful to not cause * warnings for pointer use. */ -#define __signed_type_use(ux) (2 + __is_nonneg(ux)) -#define __unsigned_type_use(ux) (1 + 2 * (sizeof(ux) < 4)) #define __sign_use(ux) (is_signed_type(typeof(ux)) ? \ - __signed_type_use(ux) : __unsigned_type_use(ux)) + (2 + __is_nonneg(ux)) : (1 + 2 * (sizeof(ux) < 4)))

/* * Check whether a signed value is always non-negative. @@ -57,7 +55,7 @@ * A cast is needed to avoid any warnings from values that aren't signed * integer types (in which case the result doesn't matter). * - * On 64-bit any integer or pointer type can safely be cast to 'long'. + * On 64-bit any integer or pointer type can safely be cast to 'long long'. * But on 32-bit we need to avoid warnings about casting pointers to integers * of different sizes without truncating 64-bit values so 'long' or 'long long' * must be used depending on the size of the value. @@ -66,12 +64,12 @@ * them, but we do not use s128 types in the kernel (we do use 'u128', * but they are handled by the !is_signed_type() case). */ -#ifdef CONFIG_64BIT - #define __signed_type(ux) long +#if __SIZEOF_POINTER__ == __SIZEOF_LONG_LONG__ +#define __is_nonneg(ux) statically_true((long long)(ux) >= 0) #else - #define __signed_type(ux) typeof(__builtin_choose_expr(sizeof(ux) > 4, 1LL, 1L)) +#define __is_nonneg(ux) statically_true( \ + (typeof(__builtin_choose_expr(sizeof(ux) > 4, 1LL, 1L)))(ux) >= 0) #endif -#define __is_nonneg(ux) statically_true((__signed_type(ux))(ux) >= 0)

#define __types_ok(ux, uy) \ (__sign_use(ux) & __sign_use(uy))