[kmods PATCH] linux/igb_uio: allow modules install

[Bruce Richardson <bruce.richardson@intel.com>]

For those still using the "igb_uio" kernel module, there may be
occasions where the module is installed in /lib/modules/$VERSION folder
rather than being insmod'ed from the build directory. To support this, a
number of changes are needed to the makefile:

* Change the "clean" command to a generic wildcard target where that
  target is just passed through to the top-level kernel makefile. This
  should allow all standard kernel module targets, including "clean" and
  "modules_install" to work.
* To install in /lib/modules, root permissions are needed, so it is
  likely that users may try installing the module using "sudo". However,
  under sudo there is often no $PWD environment variable, breaking the
  build. This can be fixed by changing the environment variable $PWD to
  the make built-in variable "CURDIR"[1].
* As a cleanup, the actual kernel module path is got directly by make
  from the shell, rather than relying on the shell substitution later
  when making the recursive make call. This improves things slightly for
  the user as the full recursive command is visible, with the kernel
  version appearing in place of `uname -r` in the output.

[1] While neither PWD nor CURDIR will work correctly in the case where
one is building outside of the sources directory, this is an edge case,
and a simple replacement of PWD by CURDIR keeps things simple while
adding support for "sudo".

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
---
 linux/igb_uio/Makefile | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/linux/igb_uio/Makefile b/linux/igb_uio/Makefile
index 09ae5d9..bd2e356 100644
--- a/linux/igb_uio/Makefile
+++ b/linux/igb_uio/Makefile
@@ -1,7 +1,7 @@
-KSRC ?= /lib/modules/`uname -r`/build
+KSRC ?= /lib/modules/$(shell uname -r)/build
 
 all:
-	make -C $(KSRC)/ M=$(PWD)
+	make -C $(KSRC)/ M=$(CURDIR)
 
-clean:
-	make -C $(KSRC)/ M=$(PWD) clean
+%:
+	make -C $(KSRC)/ M=$(CURDIR) $@
-- 
2.32.0