lib: Allow for the DIM library to be modular

Allow the Dynamic Interrupt Moderation (DIM) library to be built as a
module. This is particularly useful in an Android GKI (Google Kernel
Image) configuration where everything is built as a module, including
Ethernet controller drivers. Having to build DIMLIB into the kernel
image with potentially no user is wasteful.

Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Link: https://lore.kernel.org/r/20240506175040.410446-1-florian.fainelli@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

lib/Kconfig

@@ -628,7 +628,7 @@ config SIGNATURE
 	  Implementation is done using GnuPG MPI library
 
 config DIMLIB
-	bool
+	tristate
 	help
 	  Dynamic Interrupt Moderation library.
 	  Implements an algorithm for dynamically changing CQ moderation values

lib/dim/Makefile

@@ -2,6 +2,6 @@
 # DIM Dynamic Interrupt Moderation library
 #
 
-obj-$(CONFIG_DIMLIB) += dim.o
+obj-$(CONFIG_DIMLIB) += dimlib.o
 
-dim-y := dim.o net_dim.o rdma_dim.o
+dimlib-objs := dim.o net_dim.o rdma_dim.o

lib/dim/dim.c

@@ -82,3 +82,6 @@ bool dim_calc_stats(struct dim_sample *start, struct dim_sample *end,
 	return true;
 }
 EXPORT_SYMBOL(dim_calc_stats);
+
+MODULE_DESCRIPTION("Dynamic Interrupt Moderation (DIM) library");
+MODULE_LICENSE("Dual BSD/GPL");