xor: remove macro abuse for XOR implementation registrations

Drop the pretty confusing historic XOR_TRY_TEMPLATES and
XOR_SELECT_TEMPLATE, and instead let the architectures provide a
arch_xor_init that calls either xor_register to register candidates or
xor_force to force a specific implementation.

Link: https://lkml.kernel.org/r/20260327061704.3707577-10-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Biggers <ebiggers@kernel.org>
Tested-by: Eric Biggers <ebiggers@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: David Sterba <dsterba@suse.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason A. Donenfeld <jason@zx2c4.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Li Nan <linan122@huawei.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Song Liu <song@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 31 insertions, 10 deletions

diff --git a/lib/raid/xor/xor-core.c b/lib/raid/xor/xor-core.c
index db1824011a12..93608b5fece9 100644
--- a/lib/raid/xor/xor-core.c
+++ b/lib/raid/xor/xor-core.c
@@ -14,10 +14,6 @@
 #include <linux/preempt.h>
 #include <asm/xor.h>
 
-#ifndef XOR_SELECT_TEMPLATE
-#define XOR_SELECT_TEMPLATE(x) (x)
-#endif
-
 /* The xor routines to use.  */
 static struct xor_block_template *active_template;
 
@@ -55,12 +51,33 @@ EXPORT_SYMBOL(xor_blocks);
 static struct xor_block_template *__initdata template_list;
 static bool __initdata xor_forced = false;
 
-static void __init do_xor_register(struct xor_block_template *tmpl)
+/**
+ * xor_register - register a XOR template
+ * @tmpl:	template to register
+ *
+ * Register a XOR implementation with the core.  Registered implementations
+ * will be measured by a trivial benchmark, and the fastest one is chosen
+ * unless an implementation is forced using xor_force().
+ */
+void __init xor_register(struct xor_block_template *tmpl)
 {
 	tmpl->next = template_list;
 	template_list = tmpl;
 }
 
+/**
+ * xor_force - force use of a XOR template
+ * @tmpl:	template to register
+ *
+ * Register a XOR implementation with the core and force using it.  Forcing
+ * an implementation will make the core ignore any template registered using
+ * xor_register(), or any previous implementation forced using xor_force().
+ */
+void __init xor_force(struct xor_block_template *tmpl)
+{
+	active_template = tmpl;
+}
+
 #define BENCH_SIZE	4096
 #define REPS		800U
 
@@ -126,11 +143,19 @@ static int __init calibrate_xor_blocks(void)
 
 static int __init xor_init(void)
 {
+#ifdef arch_xor_init
+	arch_xor_init();
+#else
+	xor_register(&xor_block_8regs);
+	xor_register(&xor_block_8regs_p);
+	xor_register(&xor_block_32regs);
+	xor_register(&xor_block_32regs_p);
+#endif
+
 	/*
 	 * If this arch/cpu has a short-circuited selection, don't loop through
 	 * all the possible functions, just use the best one.
 	 */
-	active_template = XOR_SELECT_TEMPLATE(NULL);
 	if (active_template) {
 		pr_info("xor: automatically using best checksumming function   %-10s\n",
 			active_template->name);
@@ -138,10 +163,6 @@ static int __init xor_init(void)
 		return 0;
 	}
 
-#define xor_speed	do_xor_register
-	XOR_TRY_TEMPLATES;
-#undef xor_speed
-
 #ifdef MODULE
 	return calibrate_xor_blocks();
 #else