[PATCH] drm/i915: Mark expected switch fall-throughs

From: Gustavo A. R. Silva
Date: Mon Jul 22 2019 - 14:12:49 EST


In preparation to enabling -Wimplicit-fallthrough, mark switch
cases where we are expecting to fall through.

This patch fixes the following warnings:

drivers/gpu/drm/i915/gem/i915_gem_mman.c: In function âi915_gem_faultâ:
drivers/gpu/drm/i915/gem/i915_gem_mman.c:342:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
if (!i915_terminally_wedged(i915))
^
drivers/gpu/drm/i915/gem/i915_gem_mman.c:345:2: note: here
case -EAGAIN:
^~~~

drivers/gpu/drm/i915/gem/i915_gem_pages.c: In function âi915_gem_object_mapâ:
./include/linux/compiler.h:78:22: warning: this statement may fall through [-Wimplicit-fallthrough=]
# define unlikely(x) __builtin_expect(!!(x), 0)
^~~~~~~~~~~~~~~~~~~~~~~~~~
./include/asm-generic/bug.h:136:2: note: in expansion of macro âunlikelyâ
unlikely(__ret_warn_on); \
^~~~~~~~
drivers/gpu/drm/i915/i915_utils.h:49:25: note: in expansion of macro âWARNâ
#define MISSING_CASE(x) WARN(1, "Missing case (%s == %ld)\n", \
^~~~
drivers/gpu/drm/i915/gem/i915_gem_pages.c:270:3: note: in expansion of macro âMISSING_CASEâ
MISSING_CASE(type);
^~~~~~~~~~~~
drivers/gpu/drm/i915/gem/i915_gem_pages.c:272:2: note: here
case I915_MAP_WB:
^~~~

drivers/gpu/drm/i915/i915_gpu_error.c: In function âerror_record_engine_registersâ:
./include/linux/compiler.h:78:22: warning: this statement may fall through [-Wimplicit-fallthrough=]
# define unlikely(x) __builtin_expect(!!(x), 0)
^~~~~~~~~~~~~~~~~~~~~~~~~~
./include/asm-generic/bug.h:136:2: note: in expansion of macro âunlikelyâ
unlikely(__ret_warn_on); \
^~~~~~~~
drivers/gpu/drm/i915/i915_utils.h:49:25: note: in expansion of macro âWARNâ
#define MISSING_CASE(x) WARN(1, "Missing case (%s == %ld)\n", \
^~~~
drivers/gpu/drm/i915/i915_gpu_error.c:1196:5: note: in expansion of macro âMISSING_CASEâ
MISSING_CASE(engine->id);
^~~~~~~~~~~~
drivers/gpu/drm/i915/i915_gpu_error.c:1197:4: note: here
case RCS0:
^~~~

drivers/gpu/drm/i915/display/intel_dp.c: In function âintel_dp_get_fia_supported_lane_countâ:
./include/linux/compiler.h:78:22: warning: this statement may fall through [-Wimplicit-fallthrough=]
# define unlikely(x) __builtin_expect(!!(x), 0)
^~~~~~~~~~~~~~~~~~~~~~~~~~
./include/asm-generic/bug.h:136:2: note: in expansion of macro âunlikelyâ
unlikely(__ret_warn_on); \
^~~~~~~~
drivers/gpu/drm/i915/i915_utils.h:49:25: note: in expansion of macro âWARNâ
#define MISSING_CASE(x) WARN(1, "Missing case (%s == %ld)\n", \
^~~~
drivers/gpu/drm/i915/display/intel_dp.c:233:3: note: in expansion of macro âMISSING_CASEâ
MISSING_CASE(lane_info);
^~~~~~~~~~~~
drivers/gpu/drm/i915/display/intel_dp.c:234:2: note: here
case 1:
^~~~

drivers/gpu/drm/i915/display/intel_display.c: In function âcheck_digital_port_conflictsâ:
CC [M] drivers/gpu/drm/nouveau/nvkm/engine/disp/cursgv100.o
drivers/gpu/drm/i915/display/intel_display.c:12043:7: warning: this statement may fall through [-Wimplicit-fallthrough=]
if (WARN_ON(!HAS_DDI(to_i915(dev))))
^
drivers/gpu/drm/i915/display/intel_display.c:12046:3: note: here
case INTEL_OUTPUT_DP:
^~~~

Also, notice that the Makefile is modified in order to stop
ignoring fall-through warnings. The -Wimplicit-fallthrough
option will be enabled globally in v5.3.

Warning level 3 was used: -Wimplicit-fallthrough=3

This patch is part of the ongoing efforts to enable
-Wimplicit-fallthrough.

Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/Makefile | 1 -
drivers/gpu/drm/i915/display/intel_display.c | 2 +-
drivers/gpu/drm/i915/display/intel_dp.c | 1 +
drivers/gpu/drm/i915/gem/i915_gem_mman.c | 2 +-
drivers/gpu/drm/i915/gem/i915_gem_pages.c | 2 +-
drivers/gpu/drm/i915/i915_gpu_error.c | 1 +
6 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 91355c2ea8a5..8cace65f50ce 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -16,7 +16,6 @@ subdir-ccflags-y := -Wall -Wextra
subdir-ccflags-y += $(call cc-disable-warning, unused-parameter)
subdir-ccflags-y += $(call cc-disable-warning, type-limits)
subdir-ccflags-y += $(call cc-disable-warning, missing-field-initializers)
-subdir-ccflags-y += $(call cc-disable-warning, implicit-fallthrough)
subdir-ccflags-y += $(call cc-disable-warning, unused-but-set-variable)
# clang warnings
subdir-ccflags-y += $(call cc-disable-warning, sign-compare)
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 8592a7d422de..30b97ded6fdd 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -12042,7 +12042,7 @@ static bool check_digital_port_conflicts(struct intel_atomic_state *state)
case INTEL_OUTPUT_DDI:
if (WARN_ON(!HAS_DDI(to_i915(dev))))
break;
- /* else: fall through */
+ /* else, fall through */
case INTEL_OUTPUT_DP:
case INTEL_OUTPUT_HDMI:
case INTEL_OUTPUT_EDP:
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 4336df46fe78..d0fc34826771 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -231,6 +231,7 @@ static int intel_dp_get_fia_supported_lane_count(struct intel_dp *intel_dp)
switch (lane_info) {
default:
MISSING_CASE(lane_info);
+ /* fall through */
case 1:
case 2:
case 4:
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
index 391621ee3cbb..39a661927d8e 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
@@ -341,7 +341,7 @@ vm_fault_t i915_gem_fault(struct vm_fault *vmf)
*/
if (!i915_terminally_wedged(i915))
return VM_FAULT_SIGBUS;
- /* else: fall through */
+ /* else, fall through */
case -EAGAIN:
/*
* EAGAIN means the gpu is hung and we'll wait for the error
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
index b36ad269f4ea..65eb430cedba 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
@@ -268,7 +268,7 @@ static void *i915_gem_object_map(const struct drm_i915_gem_object *obj,
switch (type) {
default:
MISSING_CASE(type);
- /* fallthrough to use PAGE_KERNEL anyway */
+ /* fallthrough - to use PAGE_KERNEL anyway */
case I915_MAP_WB:
pgprot = PAGE_KERNEL;
break;
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index b7e9fddef270..41a511d5267f 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -1194,6 +1194,7 @@ static void error_record_engine_registers(struct i915_gpu_state *error,
switch (engine->id) {
default:
MISSING_CASE(engine->id);
+ /* fall through */
case RCS0:
mmio = RENDER_HWS_PGA_GEN7;
break;
--
2.22.0