Merge branch 'lib-packing-introduce-and-use-un-pack_fields'

Jacob Keller says:

====================
lib: packing: introduce and use (un)pack_fields

This series improves the packing library with a new API for packing or
unpacking a large number of fields at once with minimal code footprint. The
API is then used to replace bespoke packing logic in the ice driver,
preparing it to handle unpacking in the future. Finally, the ice driver has
a few other cleanups related to the packing logic.

The pack_fields and unpack_fields functions have the following improvements
over the existing pack() and unpack() API:

 1. Packing or unpacking a large number of fields takes significantly less
    code. This significantly reduces the .text size for an increase in the
    .data size which is much smaller.

 2. The unpacked data can be stored in sizes smaller than u64 variables.
    This reduces the storage requirement both for runtime data structures,
    and for the rodata defining the fields. This scales with the number of
    fields used.

 3. Most of the error checking is done at compile time, rather than
    runtime, via CHECK_PACKED_FIELD macros.

The actual packing and unpacking code still uses the u64 size
variables. However, these are converted to the appropriate field sizes when
storing or reading the data from the buffer.

This version now uses significantly improved macro checks, thanks to the
work of Vladimir. We now only need 300 lines of macro for the generated
checks. In addition, each new check only requires 4 lines of code for its
macro implementation and 1 extra line in the CHECK_PACKED_FIELDS macro.
This is significantly better than previous versions which required ~2700
lines.

The CHECK_PACKED_FIELDS macro uses __builtin_choose_expr to select the
appropriately sized CHECK_PACKED_FIELDS_N macro. This enables directly
adding CHECK_PACKED_FIELDS calls into the pack_fields and unpack_fields
macros. Drivers no longer need to call the CHECK_PACKED_FIELDS_N macros
directly, and we do not need to modify Kbuild or introduce multiple CONFIG
options.

The code for the CHECK_PACKED_FIELDS_(0..50) and CHECK_PACKED_FIELDS itself
can be generated from the C program in scripts/gen_packed_field_checks.c.
This little C program may be used in the future to update the checks to
more sizes if a driver with more than 50 fields appears in the future.
The total amount of required code is now much smaller, and we don't
anticipate needing to increase the size very often. Thus, it makes sense to
simply commit the result directly instead of attempting to modify Kbuild to
automatically generate it.

This version uses the 5-argument format of pack_fields and unpack_fields,
with the size of the packed buffer passed as one of the arguments. We do
enforce that the compiler can tell its a constant using
__builtin_constant_p(), ensuring that the size checks are handled at
compile time. We could reduce these to 4 arguments and require that the
passed in pbuf be of a type which has the appropriate size. I opted against
that because it makes the API less flexible and a bit less natural to use
in existing code.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>

v9: https://lore.kernel.org/20241204-packing-pack-fields-and-ice-implementation-v9-0-81c8f2bd7323@intel.com
v8: https://lore.kernel.org/20241203-packing-pack-fields-and-ice-implementation-v8-0-2ed68edfe583@intel.com
v7: https://lore.kernel.org/20241202-packing-pack-fields-and-ice-implementation-v7-0-ed22e38e6c65@intel.com
v6: https://lore.kernel.org/20241118-packing-pack-fields-and-ice-implementation-v6-0-6af8b658a6c3@intel.com
v5: https://lore.kernel.org/20241111-packing-pack-fields-and-ice-implementation-v5-0-80c07349e6b7@intel.com
v4: https://lore.kernel.org/20241108-packing-pack-fields-and-ice-implementation-v4-0-81a9f42c30e5@intel.com
v3: https://lore.kernel.org/20241107-packing-pack-fields-and-ice-implementation-v3-0-27c566ac2436@intel.com
v2: https://lore.kernel.org/20241025-packing-pack-fields-and-ice-implementation-v2-0-734776c88e40@intel.com
v1: https://lore.kernel.org/20241011-packing-pack-fields-and-ice-implementation-v1-0-d9b1f7500740@intel.com
====================

Link: https://patch.msgid.link/20241210-packing-pack-fields-and-ice-implementation-v10-0-ee56a47479ac@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 425 insertions, 0 deletions

diff --git a/include/linux/packing.h b/include/linux/packing.h
index 5d36dcd06f60..0589d70bbe04 100644
--- a/include/linux/packing.h
+++ b/include/linux/packing.h
@@ -8,6 +8,83 @@
 #include <linux/types.h>
 #include <linux/bitops.h>
 
+#define GEN_PACKED_FIELD_STRUCT(__type) \
+	struct packed_field_ ## __type { \
+		__type startbit; \
+		__type endbit; \
+		__type offset; \
+		__type size; \
+	}
+
+/* struct packed_field_u8. Use with bit offsets < 256, buffers < 32B and
+ * unpacked structures < 256B.
+ */
+GEN_PACKED_FIELD_STRUCT(u8);
+
+/* struct packed_field_u16. Use with bit offsets < 65536, buffers < 8KB and
+ * unpacked structures < 64KB.
+ */
+GEN_PACKED_FIELD_STRUCT(u16);
+
+#define PACKED_FIELD(start, end, struct_name, struct_field) \
+{ \
+	(start), \
+	(end), \
+	offsetof(struct_name, struct_field), \
+	sizeof_field(struct_name, struct_field), \
+}
+
+#define CHECK_PACKED_FIELD_OVERLAP(fields, index1, index2) ({ \
+	typeof(&(fields)[0]) __f = (fields); \
+	typeof(__f[0]) _f1 = __f[index1]; typeof(__f[0]) _f2 = __f[index2]; \
+	const bool _ascending = __f[0].startbit < __f[1].startbit; \
+	BUILD_BUG_ON_MSG(_ascending && _f1.startbit >= _f2.startbit, \
+			 __stringify(fields) " field " __stringify(index2) \
+			 " breaks ascending order"); \
+	BUILD_BUG_ON_MSG(!_ascending && _f1.startbit <= _f2.startbit, \
+			 __stringify(fields) " field " __stringify(index2) \
+			 " breaks descending order"); \
+	BUILD_BUG_ON_MSG(max(_f1.endbit, _f2.endbit) <= \
+			 min(_f1.startbit, _f2.startbit), \
+			 __stringify(fields) " field " __stringify(index2) \
+			 " overlaps with previous field"); \
+})
+
+#define CHECK_PACKED_FIELD(fields, index) ({ \
+	typeof(&(fields)[0]) _f = (fields); \
+	typeof(_f[0]) __f = _f[index]; \
+	BUILD_BUG_ON_MSG(__f.startbit < __f.endbit, \
+			 __stringify(fields) " field " __stringify(index) \
+			 " start bit must not be smaller than end bit"); \
+	BUILD_BUG_ON_MSG(__f.size != 1 && __f.size != 2 && \
+			 __f.size != 4 && __f.size != 8, \
+			 __stringify(fields) " field " __stringify(index) \
+			" has unsupported unpacked storage size"); \
+	BUILD_BUG_ON_MSG(__f.startbit - __f.endbit >= BITS_PER_BYTE * __f.size, \
+			 __stringify(fields) " field " __stringify(index) \
+			 " exceeds unpacked storage size"); \
+	__builtin_choose_expr(index != 0, \
+			      CHECK_PACKED_FIELD_OVERLAP(fields, index - 1, index), \
+			      1); \
+})
+
+/* Note that the packed fields may be either in ascending or descending order.
+ * Thus, we must check that both the first and last field wit within the
+ * packed buffer size.
+ */
+#define CHECK_PACKED_FIELDS_SIZE(fields, pbuflen) ({ \
+	typeof(&(fields)[0]) _f = (fields); \
+	typeof(pbuflen) _len = (pbuflen); \
+	const size_t num_fields = ARRAY_SIZE(fields); \
+	BUILD_BUG_ON_MSG(!__builtin_constant_p(_len), \
+			 __stringify(fields) " pbuflen " __stringify(pbuflen) \
+			 " must be a compile time constant"); \
+	BUILD_BUG_ON_MSG(_f[0].startbit >= BITS_PER_BYTE * _len, \
+			 __stringify(fields) " first field exceeds packed buffer size"); \
+	BUILD_BUG_ON_MSG(_f[num_fields - 1].startbit >= BITS_PER_BYTE * _len, \
+			 __stringify(fields) " last field exceeds packed buffer size"); \
+})
+
 #define QUIRK_MSB_ON_THE_RIGHT	BIT(0)
 #define QUIRK_LITTLE_ENDIAN	BIT(1)
 #define QUIRK_LSW32_IS_FIRST	BIT(2)
@@ -26,4 +103,352 @@ int pack(void *pbuf, u64 uval, size_t startbit, size_t endbit, size_t pbuflen,
 int unpack(const void *pbuf, u64 *uval, size_t startbit, size_t endbit,
 	   size_t pbuflen, u8 quirks);
 
+void pack_fields_u8(void *pbuf, size_t pbuflen, const void *ustruct,
+		    const struct packed_field_u8 *fields, size_t num_fields,
+		    u8 quirks);
+
+void pack_fields_u16(void *pbuf, size_t pbuflen, const void *ustruct,
+		     const struct packed_field_u16 *fields, size_t num_fields,
+		     u8 quirks);
+
+void unpack_fields_u8(const void *pbuf, size_t pbuflen, void *ustruct,
+		      const struct packed_field_u8 *fields, size_t num_fields,
+		      u8 quirks);
+
+void unpack_fields_u16(const void *pbuf, size_t pbuflen, void *ustruct,
+		       const struct packed_field_u16 *fields, size_t num_fields,
+		       u8 quirks);
+
+/* Do not hand-edit the following packed field check macros!
+ *
+ * They are generated using scripts/gen_packed_field_checks.c, which may be
+ * built via "make scripts_gen_packed_field_checks". If larger macro sizes are
+ * needed in the future, please use this program to re-generate the macros and
+ * insert them here.
+ */
+
+#define CHECK_PACKED_FIELDS_1(fields) \
+	CHECK_PACKED_FIELD(fields, 0)
+
+#define CHECK_PACKED_FIELDS_2(fields) do { \
+	CHECK_PACKED_FIELDS_1(fields); \
+	CHECK_PACKED_FIELD(fields, 1); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_3(fields) do { \
+	CHECK_PACKED_FIELDS_2(fields); \
+	CHECK_PACKED_FIELD(fields, 2); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_4(fields) do { \
+	CHECK_PACKED_FIELDS_3(fields); \
+	CHECK_PACKED_FIELD(fields, 3); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_5(fields) do { \
+	CHECK_PACKED_FIELDS_4(fields); \
+	CHECK_PACKED_FIELD(fields, 4); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_6(fields) do { \
+	CHECK_PACKED_FIELDS_5(fields); \
+	CHECK_PACKED_FIELD(fields, 5); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_7(fields) do { \
+	CHECK_PACKED_FIELDS_6(fields); \
+	CHECK_PACKED_FIELD(fields, 6); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_8(fields) do { \
+	CHECK_PACKED_FIELDS_7(fields); \
+	CHECK_PACKED_FIELD(fields, 7); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_9(fields) do { \
+	CHECK_PACKED_FIELDS_8(fields); \
+	CHECK_PACKED_FIELD(fields, 8); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_10(fields) do { \
+	CHECK_PACKED_FIELDS_9(fields); \
+	CHECK_PACKED_FIELD(fields, 9); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_11(fields) do { \
+	CHECK_PACKED_FIELDS_10(fields); \
+	CHECK_PACKED_FIELD(fields, 10); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_12(fields) do { \
+	CHECK_PACKED_FIELDS_11(fields); \
+	CHECK_PACKED_FIELD(fields, 11); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_13(fields) do { \
+	CHECK_PACKED_FIELDS_12(fields); \
+	CHECK_PACKED_FIELD(fields, 12); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_14(fields) do { \
+	CHECK_PACKED_FIELDS_13(fields); \
+	CHECK_PACKED_FIELD(fields, 13); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_15(fields) do { \
+	CHECK_PACKED_FIELDS_14(fields); \
+	CHECK_PACKED_FIELD(fields, 14); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_16(fields) do { \
+	CHECK_PACKED_FIELDS_15(fields); \
+	CHECK_PACKED_FIELD(fields, 15); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_17(fields) do { \
+	CHECK_PACKED_FIELDS_16(fields); \
+	CHECK_PACKED_FIELD(fields, 16); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_18(fields) do { \
+	CHECK_PACKED_FIELDS_17(fields); \
+	CHECK_PACKED_FIELD(fields, 17); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_19(fields) do { \
+	CHECK_PACKED_FIELDS_18(fields); \
+	CHECK_PACKED_FIELD(fields, 18); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_20(fields) do { \
+	CHECK_PACKED_FIELDS_19(fields); \
+	CHECK_PACKED_FIELD(fields, 19); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_21(fields) do { \
+	CHECK_PACKED_FIELDS_20(fields); \
+	CHECK_PACKED_FIELD(fields, 20); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_22(fields) do { \
+	CHECK_PACKED_FIELDS_21(fields); \
+	CHECK_PACKED_FIELD(fields, 21); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_23(fields) do { \
+	CHECK_PACKED_FIELDS_22(fields); \
+	CHECK_PACKED_FIELD(fields, 22); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_24(fields) do { \
+	CHECK_PACKED_FIELDS_23(fields); \
+	CHECK_PACKED_FIELD(fields, 23); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_25(fields) do { \
+	CHECK_PACKED_FIELDS_24(fields); \
+	CHECK_PACKED_FIELD(fields, 24); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_26(fields) do { \
+	CHECK_PACKED_FIELDS_25(fields); \
+	CHECK_PACKED_FIELD(fields, 25); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_27(fields) do { \
+	CHECK_PACKED_FIELDS_26(fields); \
+	CHECK_PACKED_FIELD(fields, 26); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_28(fields) do { \
+	CHECK_PACKED_FIELDS_27(fields); \
+	CHECK_PACKED_FIELD(fields, 27); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_29(fields) do { \
+	CHECK_PACKED_FIELDS_28(fields); \
+	CHECK_PACKED_FIELD(fields, 28); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_30(fields) do { \
+	CHECK_PACKED_FIELDS_29(fields); \
+	CHECK_PACKED_FIELD(fields, 29); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_31(fields) do { \
+	CHECK_PACKED_FIELDS_30(fields); \
+	CHECK_PACKED_FIELD(fields, 30); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_32(fields) do { \
+	CHECK_PACKED_FIELDS_31(fields); \
+	CHECK_PACKED_FIELD(fields, 31); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_33(fields) do { \
+	CHECK_PACKED_FIELDS_32(fields); \
+	CHECK_PACKED_FIELD(fields, 32); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_34(fields) do { \
+	CHECK_PACKED_FIELDS_33(fields); \
+	CHECK_PACKED_FIELD(fields, 33); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_35(fields) do { \
+	CHECK_PACKED_FIELDS_34(fields); \
+	CHECK_PACKED_FIELD(fields, 34); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_36(fields) do { \
+	CHECK_PACKED_FIELDS_35(fields); \
+	CHECK_PACKED_FIELD(fields, 35); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_37(fields) do { \
+	CHECK_PACKED_FIELDS_36(fields); \
+	CHECK_PACKED_FIELD(fields, 36); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_38(fields) do { \
+	CHECK_PACKED_FIELDS_37(fields); \
+	CHECK_PACKED_FIELD(fields, 37); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_39(fields) do { \
+	CHECK_PACKED_FIELDS_38(fields); \
+	CHECK_PACKED_FIELD(fields, 38); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_40(fields) do { \
+	CHECK_PACKED_FIELDS_39(fields); \
+	CHECK_PACKED_FIELD(fields, 39); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_41(fields) do { \
+	CHECK_PACKED_FIELDS_40(fields); \
+	CHECK_PACKED_FIELD(fields, 40); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_42(fields) do { \
+	CHECK_PACKED_FIELDS_41(fields); \
+	CHECK_PACKED_FIELD(fields, 41); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_43(fields) do { \
+	CHECK_PACKED_FIELDS_42(fields); \
+	CHECK_PACKED_FIELD(fields, 42); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_44(fields) do { \
+	CHECK_PACKED_FIELDS_43(fields); \
+	CHECK_PACKED_FIELD(fields, 43); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_45(fields) do { \
+	CHECK_PACKED_FIELDS_44(fields); \
+	CHECK_PACKED_FIELD(fields, 44); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_46(fields) do { \
+	CHECK_PACKED_FIELDS_45(fields); \
+	CHECK_PACKED_FIELD(fields, 45); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_47(fields) do { \
+	CHECK_PACKED_FIELDS_46(fields); \
+	CHECK_PACKED_FIELD(fields, 46); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_48(fields) do { \
+	CHECK_PACKED_FIELDS_47(fields); \
+	CHECK_PACKED_FIELD(fields, 47); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_49(fields) do { \
+	CHECK_PACKED_FIELDS_48(fields); \
+	CHECK_PACKED_FIELD(fields, 48); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS_50(fields) do { \
+	CHECK_PACKED_FIELDS_49(fields); \
+	CHECK_PACKED_FIELD(fields, 49); \
+} while (0)
+
+#define CHECK_PACKED_FIELDS(fields) \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 1, ({ CHECK_PACKED_FIELDS_1(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 2, ({ CHECK_PACKED_FIELDS_2(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 3, ({ CHECK_PACKED_FIELDS_3(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 4, ({ CHECK_PACKED_FIELDS_4(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 5, ({ CHECK_PACKED_FIELDS_5(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 6, ({ CHECK_PACKED_FIELDS_6(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 7, ({ CHECK_PACKED_FIELDS_7(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 8, ({ CHECK_PACKED_FIELDS_8(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 9, ({ CHECK_PACKED_FIELDS_9(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 10, ({ CHECK_PACKED_FIELDS_10(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 11, ({ CHECK_PACKED_FIELDS_11(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 12, ({ CHECK_PACKED_FIELDS_12(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 13, ({ CHECK_PACKED_FIELDS_13(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 14, ({ CHECK_PACKED_FIELDS_14(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 15, ({ CHECK_PACKED_FIELDS_15(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 16, ({ CHECK_PACKED_FIELDS_16(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 17, ({ CHECK_PACKED_FIELDS_17(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 18, ({ CHECK_PACKED_FIELDS_18(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 19, ({ CHECK_PACKED_FIELDS_19(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 20, ({ CHECK_PACKED_FIELDS_20(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 21, ({ CHECK_PACKED_FIELDS_21(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 22, ({ CHECK_PACKED_FIELDS_22(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 23, ({ CHECK_PACKED_FIELDS_23(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 24, ({ CHECK_PACKED_FIELDS_24(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 25, ({ CHECK_PACKED_FIELDS_25(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 26, ({ CHECK_PACKED_FIELDS_26(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 27, ({ CHECK_PACKED_FIELDS_27(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 28, ({ CHECK_PACKED_FIELDS_28(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 29, ({ CHECK_PACKED_FIELDS_29(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 30, ({ CHECK_PACKED_FIELDS_30(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 31, ({ CHECK_PACKED_FIELDS_31(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 32, ({ CHECK_PACKED_FIELDS_32(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 33, ({ CHECK_PACKED_FIELDS_33(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 34, ({ CHECK_PACKED_FIELDS_34(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 35, ({ CHECK_PACKED_FIELDS_35(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 36, ({ CHECK_PACKED_FIELDS_36(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 37, ({ CHECK_PACKED_FIELDS_37(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 38, ({ CHECK_PACKED_FIELDS_38(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 39, ({ CHECK_PACKED_FIELDS_39(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 40, ({ CHECK_PACKED_FIELDS_40(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 41, ({ CHECK_PACKED_FIELDS_41(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 42, ({ CHECK_PACKED_FIELDS_42(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 43, ({ CHECK_PACKED_FIELDS_43(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 44, ({ CHECK_PACKED_FIELDS_44(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 45, ({ CHECK_PACKED_FIELDS_45(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 46, ({ CHECK_PACKED_FIELDS_46(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 47, ({ CHECK_PACKED_FIELDS_47(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 48, ({ CHECK_PACKED_FIELDS_48(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 49, ({ CHECK_PACKED_FIELDS_49(fields); }), \
+	__builtin_choose_expr(ARRAY_SIZE(fields) == 50, ({ CHECK_PACKED_FIELDS_50(fields); }), \
+	({ BUILD_BUG_ON_MSG(1, "CHECK_PACKED_FIELDS() must be regenerated to support array sizes larger than 50."); }) \
+))))))))))))))))))))))))))))))))))))))))))))))))))
+
+/* End of generated content */
+
+#define pack_fields(pbuf, pbuflen, ustruct, fields, quirks) \
+	({ \
+		CHECK_PACKED_FIELDS(fields); \
+		CHECK_PACKED_FIELDS_SIZE((fields), (pbuflen)); \
+		_Generic((fields), \
+			 const struct packed_field_u8 * : pack_fields_u8, \
+			 const struct packed_field_u16 * : pack_fields_u16 \
+			)((pbuf), (pbuflen), (ustruct), (fields), ARRAY_SIZE(fields), (quirks)); \
+	})
+
+#define unpack_fields(pbuf, pbuflen, ustruct, fields, quirks) \
+	({ \
+		CHECK_PACKED_FIELDS(fields); \
+		CHECK_PACKED_FIELDS_SIZE((fields), (pbuflen)); \
+		_Generic((fields), \
+			 const struct packed_field_u8 * : unpack_fields_u8, \
+			 const struct packed_field_u16 * : unpack_fields_u16 \
+			)((pbuf), (pbuflen), (ustruct), (fields), ARRAY_SIZE(fields), (quirks)); \
+	})
+
 #endif