warning: tentative array definition assumed to have one element

[nickdesaulniers]

  CC      drivers/crypto/ccp/sp-platform.o
drivers/crypto/ccp/sp-platform.c:36:36: warning: tentative array definition assumed to
      have one element
static const struct acpi_device_id sp_acpi_match[];
                                   ^

I have never seen this construct before.

Probably needs to be defined to length 1, but it's used case needs to be checked (I have not yet done so). cc @kees

Maybe needs CONFIG_CRYPTO_DEV_SP_CCP=y.

[nathanchance]

Maybe the actual defintions at the bottom of the file need to be moved up like so?

diff --git a/drivers/crypto/ccp/sp-platform.c b/drivers/crypto/ccp/sp-platform.c
index 71734f254fd1..b75dc7db2d4a 100644
--- a/drivers/crypto/ccp/sp-platform.c
+++ b/drivers/crypto/ccp/sp-platform.c
@@ -33,8 +33,31 @@ struct sp_platform {
        unsigned int irq_count;
 };
 
-static const struct acpi_device_id sp_acpi_match[];
-static const struct of_device_id sp_of_match[];
+static const struct sp_dev_vdata dev_vdata[] = {
+       {
+               .bar = 0,
+#ifdef CONFIG_CRYPTO_DEV_SP_CCP
+               .ccp_vdata = &ccpv3_platform,
+#endif
+       },
+};
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id sp_acpi_match[] = {
+       { "AMDI0C00", (kernel_ulong_t)&dev_vdata[0] },
+       { },
+};
+MODULE_DEVICE_TABLE(acpi, sp_acpi_match);
+#endif
+
+#ifdef CONFIG_OF
+static const struct of_device_id sp_of_match[] = {
+       { .compatible = "amd,ccp-seattle-v1a",
+         .data = (const void *)&dev_vdata[0] },
+       { },
+};
+MODULE_DEVICE_TABLE(of, sp_of_match);
+#endif
 
 static struct sp_dev_vdata *sp_get_of_version(struct platform_device *pdev)
 {
@@ -201,32 +224,6 @@ static int sp_platform_resume(struct platform_device *pdev)
 }
 #endif
 
-static const struct sp_dev_vdata dev_vdata[] = {
-       {
-               .bar = 0,
-#ifdef CONFIG_CRYPTO_DEV_SP_CCP
-               .ccp_vdata = &ccpv3_platform,
-#endif
-       },
-};
-
-#ifdef CONFIG_ACPI
-static const struct acpi_device_id sp_acpi_match[] = {
-       { "AMDI0C00", (kernel_ulong_t)&dev_vdata[0] },
-       { },
-};
-MODULE_DEVICE_TABLE(acpi, sp_acpi_match);
-#endif
-
-#ifdef CONFIG_OF
-static const struct of_device_id sp_of_match[] = {
-       { .compatible = "amd,ccp-seattle-v1a",
-         .data = (const void *)&dev_vdata[0] },
-       { },
-};
-MODULE_DEVICE_TABLE(of, sp_of_match);
-#endif
-
 static struct platform_driver sp_platform_driver = {
        .driver = {
                .name = "ccp",

Seems super wrong but this is the only instance of this construct in the kernel tree:

nathan@flashbox ~/kernels/next (master >) $ rg "static const struct acpi_device_id" | rg -v -F "{"
drivers/perf/xgene_pmu.c:static const struct acpi_device_id *xgene_pmu_acpi_match_type(
drivers/crypto/ccp/sp-platform.c:static const struct acpi_device_id sp_acpi_match[];
drivers/net/ethernet/amd/xgbe/xgbe-platform.c:static const struct acpi_device_id xgbe_acpi_match[];
drivers/net/ethernet/apm/xgene/xgene_enet_main.c:static const struct acpi_device_id xgene_enet_acpi_match[];
drivers/net/ethernet/apm/xgene-v2/main.c:static const struct acpi_device_id xge_acpi_match[];

The use case is checking the version:

static struct sp_dev_vdata *sp_get_acpi_version(struct platform_device *pdev)
{
#ifdef CONFIG_ACPI
        const struct acpi_device_id *match;

        match = acpi_match_device(sp_acpi_match, &pdev->dev);
        if (match && match->driver_data)
                return (struct sp_dev_vdata *)match->driver_data;
#endif
        return NULL;
}

which is used in the probe function.

[nickdesaulniers]

The forward declaration is the wrong size. I don't see the point of forward declaring the array (just initialize it), so either your suggested change or simply:

-static const struct acpi_device_id sp_acpi_match[];
+static const struct acpi_device_id sp_acpi_match[2];

[nathanchance]

Will verify and send my change upstream tomorrow (will cc you) and see what the maintainers say, thanks for the comment.

[nathanchance]

Patch sent: https://lore.kernel.org/lkml/20180924172615.25591-1-natechancellor@gmail.com/