acpi/nfit: Require opt-in for read-only label configurations
authorDan Williams <dan.j.williams@intel.com>
Sun, 3 Feb 2019 19:17:27 +0000 (11:17 -0800)
committerDan Williams <dan.j.williams@intel.com>
Wed, 13 Feb 2019 04:14:15 +0000 (20:14 -0800)
commit0171b6b78131110a6870d4b7296bc9dfc392116a
treec2286a77005b66fe1895a0ba885ada2864a6b05a
parentd5d30d5a5c60628de5e77e3f292a8f9012d51350
acpi/nfit: Require opt-in for read-only label configurations

Recent fixes to command handling enabled Linux to read label
configurations that it could not before. Unfortunately that means that
configurations that were operating in label-less mode will be broken as
the kernel ignores the existing namespace configuration and tries to
honor the new found labels.

Fortunately this seems limited to a case where Linux can quirk the
behavior and maintain the existing label-less semantics by default.
When the platform does not emit an _LSW method, disable all label access
methods. Provide a 'force_labels' module parameter to allow read-only
label operation.

Fixes: 11189c1089da ("acpi/nfit: Fix command-supported detection")
Reported-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
drivers/acpi/nfit/core.c