BKL: introduce CONFIG_BKL.

With all the patches we have queued in the BKL removal tree, only a
few dozen modules are left that actually rely on the BKL, and even
there are lots of low-hanging fruit. We need to decide what to do
about them, this patch illustrates one of the options:

Every user of the BKL is marked as 'depends on BKL' in Kconfig,
and the CONFIG_BKL becomes a user-visible option. If it gets
disabled, no BKL using module can be built any more and the BKL
code itself is compiled out.

The one exception is file locking, which is practically always
enabled and does a 'select BKL' instead. This effectively forces
CONFIG_BKL to be enabled until we have solved the fs/lockd
mess and can apply the patch that removes the BKL from fs/locks.c.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 4cab0c6397e3..7af443672626 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -73,7 +73,8 @@ source "drivers/gpu/drm/radeon/Kconfig"
 
 config DRM_I810
         tristate "Intel I810"
-        depends on DRM && AGP && AGP_INTEL
+        # BKL usage in order to avoid AB-BA deadlocks, may become BROKEN_ON_SMP
+        depends on DRM && AGP && AGP_INTEL && BKL
         help
           Choose this option if you have an Intel I810 graphics card.  If M is
           selected, the module will be called i810.  AGP support is required
@@ -86,6 +87,8 @@ choice
 
 config DRM_I830
         tristate "i830 driver"
+        # BKL usage in order to avoid AB-BA deadlocks, i830 may get removed
+        depends on BKL
         help
           Choose this option if you have a system that has Intel 830M, 845G,
           852GM, 855GM or 865G integrated graphics.  If M is selected, the