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Subject[PATCH v2 2/2] bitfield.h: split up __BF_FIELD_CHECK macro
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This macro has a few expansion sites that pass literal 0s as parameters.
Split these up so that we do the precise checks where we care about
them.

Suggested-by: Alex Elder <elder@linaro.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
Changes V1-V2:
* New patch in v2.
* Rebased on 0001.

.../netronome/nfp/nfpcore/nfp_nsp_eth.c | 11 ++++----
include/linux/bitfield.h | 26 +++++++++++++------
2 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp_eth.c b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp_eth.c
index 311a5be25acb..938fc733fccb 100644
--- a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp_eth.c
+++ b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp_eth.c
@@ -492,11 +492,12 @@ nfp_eth_set_bit_config(struct nfp_nsp *nsp, unsigned int raw_idx,
return 0;
}

-#define NFP_ETH_SET_BIT_CONFIG(nsp, raw_idx, mask, val, ctrl_bit) \
- ({ \
- __BF_FIELD_CHECK(mask, 0ULL, val, "NFP_ETH_SET_BIT_CONFIG: "); \
- nfp_eth_set_bit_config(nsp, raw_idx, mask, __bf_shf(mask), \
- val, ctrl_bit); \
+#define NFP_ETH_SET_BIT_CONFIG(nsp, raw_idx, mask, val, ctrl_bit) \
+ ({ \
+ __BF_FIELD_CHECK_MASK(mask, "NFP_ETH_SET_BIT_CONFIG: "); \
+ __BF_FIELD_CHECK_VAL(mask, val, "NFP_ETH_SET_BIT_CONFIG: "); \
+ nfp_eth_set_bit_config(nsp, raw_idx, mask, __bf_shf(mask), \
+ val, ctrl_bit); \
})

/**
diff --git a/include/linux/bitfield.h b/include/linux/bitfield.h
index 4e035aca6f7e..79651867beb3 100644
--- a/include/linux/bitfield.h
+++ b/include/linux/bitfield.h
@@ -41,18 +41,26 @@

#define __bf_shf(x) (__builtin_ffsll(x) - 1)

-#define __BF_FIELD_CHECK(_mask, _reg, _val, _pfx) \
+#define __BF_FIELD_CHECK_MASK(_mask, _pfx) \
({ \
BUILD_BUG_ON_MSG(!__builtin_constant_p(_mask), \
_pfx "mask is not constant"); \
BUILD_BUG_ON_MSG((_mask) == 0, _pfx "mask is zero"); \
+ __BUILD_BUG_ON_NOT_POWER_OF_2((_mask) + \
+ (1ULL << __bf_shf(_mask))); \
+ })
+
+#define __BF_FIELD_CHECK_VAL(_mask, _val, _pfx) \
+ ({ \
BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ? \
~((_mask) >> __bf_shf(_mask)) & (_val) : 0, \
_pfx "value too large for the field"); \
- BUILD_BUG_ON_MSG((_mask) > (typeof(_reg))~0ull, \
+ })
+
+#define __BF_FIELD_CHECK_REG(_mask, _reg, _pfx) \
+ ({ \
+ BUILD_BUG_ON_MSG((_mask) > (typeof(_reg))~0ULL, \
_pfx "type of reg too small for mask"); \
- __BUILD_BUG_ON_NOT_POWER_OF_2((_mask) + \
- (1ULL << __bf_shf(_mask))); \
})

/**
@@ -64,7 +72,7 @@
*/
#define FIELD_MAX(_mask) \
({ \
- __BF_FIELD_CHECK(_mask, 0ULL, 0ULL, "FIELD_MAX: "); \
+ __BF_FIELD_CHECK_MASK(_mask, "FIELD_MAX: "); \
(typeof(_mask))((_mask) >> __bf_shf(_mask)); \
})

@@ -77,7 +85,7 @@
*/
#define FIELD_FIT(_mask, _val) \
({ \
- __BF_FIELD_CHECK(_mask, 0ULL, 0ULL, "FIELD_FIT: "); \
+ __BF_FIELD_CHECK_MASK(_mask, "FIELD_FIT: "); \
!((((typeof(_mask))_val) << __bf_shf(_mask)) & ~(_mask)); \
})

@@ -91,7 +99,8 @@
*/
#define FIELD_PREP(_mask, _val) \
({ \
- __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: "); \
+ __BF_FIELD_CHECK_MASK(_mask, "FIELD_PREP: "); \
+ __BF_FIELD_CHECK_VAL(_mask, _val, "FIELD_PREP: "); \
((typeof(_mask))(_val) << __bf_shf(_mask)) & (_mask); \
})

@@ -105,7 +114,8 @@
*/
#define FIELD_GET(_mask, _reg) \
({ \
- __BF_FIELD_CHECK(_mask, _reg, 0U, "FIELD_GET: "); \
+ __BF_FIELD_CHECK_MASK(_mask, "FIELD_GET: "); \
+ __BF_FIELD_CHECK_REG(_mask, _reg, "FIELD_GET: "); \
(typeof(_mask))(((_reg) & (_mask)) >> __bf_shf(_mask)); \
})

--
2.27.0.383.g050319c2ae-goog
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