On Thu Jan 8, 2026 at 5:57 PM CET, Miquel Raynal wrote:
> In the case of the first block being locked (or the few first blocks),
> if the user want to fully unlock the device it has two possibilities:
> - either it asks to unlock the entire device, and this works;
> - or it asks to unlock just the block(s) that are currently locked,
>   which fails.
>
> It fails because the conditions "can_be_top" and "can_be_bottom" are
> true. Indeed, in this case, we unlock everything, so the TB bit does not
> matter. However in the current implementation, use_top would be true (as
> this is the favourite option) and lock_len, which in practice should be
> reduced down to 0, is set to "nor->params->size - (ofs + len)" which is
> a positive number. This is wrong.
>
> An easy way is to simply add an extra condition. In the unlock() path,
> if we can achieve the same result from both sides, it means we unlock
> everything and lock_len must simply be 0. A comment is added to clarify
> that logic.
>
> Fixes: 3dd8012a8eeb ("mtd: spi-nor: add TB (Top/Bottom) protect support")
> Cc: stable@kernel.org
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

Reviewed-by: Michael Walle <mwalle@kernel.org>