[PATCH 14/16] linux-custom: Simplify and clarify KERNEL_NAME-to-recipe matching

[Jan Kiszka <jan.kiszka@siemens.com>]

From: Jan Kiszka <jan.kiszka@siemens.com>

The old mechanism tried to be too smart my deriving missing elements
when defining the PROVIDES of a custom kernel recipe from the currently
selected target KERNEL_NAME. But that broke when there was both a
linux-foo and a linux-foo-bar.

Let's make it straight and simple: A custom kernel recipe can control
the suffix "[-featureset]-flavor" of the generated linux-{image,headers}
meta packages by

 a) calling itself "linux-featureset-flavor"
 b) setting the variable KERNEL_NAME_PRODVIDED to "featureset-flavor"

Effectively, KERNEL_NAME is now matched against KERNEL_NAME_PRODVIDED
(in practice, the meta package names are matched). Actually, this is the
same logic that was already used for distro kernels.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 RECIPE-API-CHANGELOG.md                    |  8 ++++++++
 meta/recipes-kernel/linux/linux-custom.inc | 10 ++++------
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/RECIPE-API-CHANGELOG.md b/RECIPE-API-CHANGELOG.md
index 69c36fa..8d93ef4 100644
--- a/RECIPE-API-CHANGELOG.md
+++ b/RECIPE-API-CHANGELOG.md
@@ -64,3 +64,11 @@ These variables can be removed from own machine.conf or multiconfig files.
 
 If you want to enable support for QEMU in your config (start_vm), specify the
 `QEMU_ROOTFS_DEV` and `QEMU_DISK_ARGS` instead.
+
+### KERNEL_NAME_PROVIDED replaces KERNEL_FLAVOR in custom kernels
+
+The matching logic for custom kernel recipes to the selected kernel was
+reworked and simplified. If your kernel recipe is called `linux-foo_4.18.bb`,
+you now have to set `KERNEL_NAME = "foo"` in order to select that kernel.
+Alternatively, a recipe with a different naming scheme can set
+`KERNEL_NAME_PROVIDED = "foo"` in order to match as well.
diff --git a/meta/recipes-kernel/linux/linux-custom.inc b/meta/recipes-kernel/linux/linux-custom.inc
index 4144b67..10a50c3 100644
--- a/meta/recipes-kernel/linux/linux-custom.inc
+++ b/meta/recipes-kernel/linux/linux-custom.inc
@@ -9,15 +9,13 @@ FILESPATH =. "${LAYERDIR_core}/recipes-kernel/linux/files:"
 
 DESCRIPTION ?= "Custom kernel"
 
-KERNEL_FLAVOR ?= "${@ d.getVar('PN', True).partition('linux-')[2]}"
+KERNEL_NAME_PRODVIDED ?= "${@ d.getVar('PN', True).partition('linux-')[2]}"
 KERNEL_DEFCONFIG ?= "defconfig"
 
 python() {
-    kernel = d.getVar("KERNEL_NAME", True)
-    flavor = d.getVar("KERNEL_FLAVOR", True)
-    if kernel and flavor and kernel.startswith(flavor + "-"):
-        d.setVar('PROVIDES', 'linux-image-' + kernel + ' ' + \
-                             'linux-headers-' + kernel)
+    kernel_name = d.getVar("KERNEL_NAME_PRODVIDED", True)
+    d.setVar('PROVIDES', 'linux-image-' + kernel_name + ' ' + \
+                         'linux-headers-' + kernel_name)
 }
 
 inherit dpkg-base
-- 
2.16.4