net: sfp: allow prefix matching in quirk lookup

Some clone SFP modules return EEPROM reads where the vendor PN field
contains non-printable garbage past the trailing legitimate characters
instead of the SFF-8472 mandated space padding. The current sfp_match()
requires an exact full-field length match: sfp_strlen() returns 16 (no
trailing spaces or NULs to strip), but strlen() of the quirk string is
shorter, so the length comparison rejects the entry before strncmp() is
even called and the quirk silently never applies.

Add a part_prefix_match flag to struct sfp_quirk and a
SFP_QUIRK_F_PREFIX macro. When set, sfp_match() compares only strlen()
leading bytes of the quirk part string, ignoring trailing field bytes.
The vendor name comparison always stays exact. Existing exact-match
quirks are unaffected (part_prefix_match defaults to false via zero-init
in the existing SFP_QUIRK macros).

This patch only adds the mechanism; the first user is added by the
following patch.

Signed-off-by: Martino Dell'Ambrogio <tillo@tillo.ch>
Link: https://patch.msgid.link/20260812154708.2201266-2-tillo@tillo.ch
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions