Merge branch 'packing-various-improvements-and-kunit-tests'

Jacob Keller says:

====================
packing: various improvements and KUnit tests

This series contains a handful of improvements and fixes for the packing
library, including the addition of KUnit tests.

There are two major changes which might be considered bug fixes:

1) The library is updated to handle arbitrary buffer lengths, fixing
   undefined behavior when operating on buffers which are not a multiple
   of 4 bytes.

2) The behavior of QUIRK_MSB_ON_THE_RIGHT is fixed to match the intended
   behavior when operating on packings that are not byte aligned.

These are not sent to net because no driver currently depends on this
behavior. For (1), the existing users of the packing API all operate on
buffers which are multiples of 4-bytes. For (2), no driver currently uses
QUIRK_MSB_ON_THE_RIGHT. The incorrect behavior was found while writing
KUnit tests.

This series also includes a handful of minor cleanups from Vladimir, as
well as a change to introduce a separated pack() and unpack() API. This API
is not (yet) used by a driver, but is the first step in implementing
pack_fields() and unpack_fields() which will be used in future changes for
the ice driver and changes Vladimir has in progress for other drivers using
the packing API.

This series is part 1 of a 2-part series for implementing use of
lib/packing in the ice driver. The 2nd part includes a new pack_fields()
and unpack_fields() implementation inspired by the ice driver's existing
bit packing code. It is built on top of the split pack() and unpack()
code. Additionally, the KUnit tests are built on top of pack() and
unpack(), based on original selftests written by Vladimir.

Fitting the entire library changes and drivers changes into a single series
exceeded the usual series limits.

v1: https://lore.kernel.org/r/20240930-packing-kunit-tests-and-split-pack-unpack-v1-0-94b1f04aca85@intel.com
====================

Link: https://patch.msgid.link/20241002-packing-kunit-tests-and-split-pack-unpack-v2-0-8373e551eae3@intel.com
Signed-off-by: Jakub Kicinski <[email protected]>

1 files changed, 6 insertions, 26 deletions

diff --git a/include/linux/packing.h b/include/linux/packing.h
index 8d6571feb95d..5d36dcd06f60 100644
--- a/include/linux/packing.h
+++ b/include/linux/packing.h
@@ -17,33 +17,13 @@ enum packing_op {
 	UNPACK,
 };
 
-/**
- * packing - Convert numbers (currently u64) between a packed and an unpacked
- *	     format. Unpacked means laid out in memory in the CPU's native
- *	     understanding of integers, while packed means anything else that
- *	     requires translation.
- *
- * @pbuf: Pointer to a buffer holding the packed value.
- * @uval: Pointer to an u64 holding the unpacked value.
- * @startbit: The index (in logical notation, compensated for quirks) where
- *	      the packed value starts within pbuf. Must be larger than, or
- *	      equal to, endbit.
- * @endbit: The index (in logical notation, compensated for quirks) where
- *	    the packed value ends within pbuf. Must be smaller than, or equal
- *	    to, startbit.
- * @op: If PACK, then uval will be treated as const pointer and copied (packed)
- *	into pbuf, between startbit and endbit.
- *	If UNPACK, then pbuf will be treated as const pointer and the logical
- *	value between startbit and endbit will be copied (unpacked) to uval.
- * @quirks: A bit mask of QUIRK_LITTLE_ENDIAN, QUIRK_LSW32_IS_FIRST and
- *	    QUIRK_MSB_ON_THE_RIGHT.
- *
- * Return: 0 on success, EINVAL or ERANGE if called incorrectly. Assuming
- *	   correct usage, return code may be discarded.
- *	   If op is PACK, pbuf is modified.
- *	   If op is UNPACK, uval is modified.
- */
 int packing(void *pbuf, u64 *uval, int startbit, int endbit, size_t pbuflen,
 	    enum packing_op op, u8 quirks);
 
+int pack(void *pbuf, u64 uval, size_t startbit, size_t endbit, size_t pbuflen,
+	 u8 quirks);
+
+int unpack(const void *pbuf, u64 *uval, size_t startbit, size_t endbit,
+	   size_t pbuflen, u8 quirks);
+
 #endif