Re: [PATCH net-next v16 3/5] net: dsa: motorcomm: use fixed-width GENMASK_U*() helpers

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- [Medium] The commit message for "net: dsa: motorcomm: use fixed-width
  GENMASK_U*() helpers" does not match the diff, in three ways.

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net: dsa: motorcomm: use fixed-width GENMASK_U*() helpers

This commit changes two GENMASK() uses in the YT921x DSA driver to
GENMASK_U32(): the FILTER_UNK value in yt921x_chip_setup_dsa(), and the
mii_bus phy_mask in yt921x_mbus_int_init(). The commit message describes
it as a type-only cleanup with no functional change.

> Some masks assigned to u16 and u32 fields are defined with
> GENMASK(),which is an unsigned long constant and wider than
> the field type on 64-bit builds. Convert the YT921X_MBUS_CTRL_*
> masks used by mdio_bus.c to fixed-width helpers.
>
> This is a type cleanup only, with no functional change. Other
> GENMASK() uses in the driver are intentionally left untouched.

[Severity: Medium]
Does this description match the diff?

The patch doesn't modify drivers/net/dsa/motorcomm/mdio_bus.h, and the
YT921X_MBUS_CTRL_* masks there still use plain GENMASK():

#define  YT921X_MBUS_CTRL_PORT_M		GENMASK(25, 21)
#define  YT921X_MBUS_CTRL_REG_M			GENMASK(20, 16)
#define  YT921X_MBUS_CTRL_TYPE_M		GENMASK(11, 8)  /* wild guess */
#define  YT921X_MBUS_CTRL_OP_M			GENMASK(3, 2)  /* wild guess */

They are still combined into u32 locals in yt921x_intif_read(),
yt921x_intif_write(), yt921x_extif_read() and yt921x_extif_write(). For
example:

	mask = YT921X_MBUS_CTRL_PORT_M | YT921X_MBUS_CTRL_REG_M |
	       YT921X_MBUS_CTRL_OP_M;

The only change in mdio_bus.c is the phy_mask expression in
yt921x_mbus_int_init(), and that is not a YT921X_MBUS_CTRL_* mask:

	mbus->phy_mask = ~GENMASK_U32(max_ports - 1, 0);

Later patches in the series don't seem to convert these masks either.

The message also says other GENMASK() uses are left untouched, but the
patch changes the open-coded value in yt921x_chip_setup_dsa() in chip.c:

	ctrl = GENMASK_U32(10, 0);
	res = yt921x_reg_write(priv, YT921X_FILTER_UNK_UCAST, ctrl);

The message doesn't mention this change. The named mask for the same
field, YT921X_FILTER_PORTS_M in chip.h, is still GENMASK(10, 0).

Both changed sites are u32, so the reference to "u16 and u32 fields"
doesn't match the diff either.

The message may describe a different version of this patch. Could it be
rewritten to describe the two conversions that are actually made? The
other option would be to convert the mdio_bus.h masks as described, and
then drop or explain the chip.c hunk.

-- 
Sashiko AI review · https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20261020111115.3072180-1-kyle.switch%40motor-comm.com