From: Arnd Bergmann <arnd@xxxxxxxx> [ Upstream commit 59d63de076607a9334b11628b5c3ddda1d8f56cd ] Clang points out a syntax error, as the etr_catu_buf_ops structure is declared 'static' before the type is known: In file included from drivers/hwtracing/coresight/coresight-tmc-etr.c:12: drivers/hwtracing/coresight/coresight-catu.h:116:40: warning: tentative definition of variable with internal linkage has incomplete non-array type 'const struct etr_buf_operations' [-Wtentative-definition-incomplete-type] static const struct etr_buf_operations etr_catu_buf_ops; ^ drivers/hwtracing/coresight/coresight-catu.h:116:21: note: forward declaration of 'struct etr_buf_operations' static const struct etr_buf_operations etr_catu_buf_ops; This seems worth fixing in the code, so replace pointer to the empty constant structure with a NULL pointer. We need an extra NULL pointer check here, but the result should be better object code otherwise, avoiding the silly empty structure. Fixes: 434d611cddef ("coresight: catu: Plug in CATU as a backend for ETR buffer") Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> Reviewed-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx> [Fixed line over 80 characters] Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/hwtracing/coresight/coresight-catu.h | 5 ----- drivers/hwtracing/coresight/coresight-tmc-etr.c | 5 +++-- 2 files changed, 3 insertions(+), 7 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-catu.h b/drivers/hwtracing/coresight/coresight-catu.h index 1b281f0dcccc..1d2ad183fd92 100644 --- a/drivers/hwtracing/coresight/coresight-catu.h +++ b/drivers/hwtracing/coresight/coresight-catu.h @@ -109,11 +109,6 @@ static inline bool coresight_is_catu_device(struct coresight_device *csdev) return true; } -#ifdef CONFIG_CORESIGHT_CATU extern const struct etr_buf_operations etr_catu_buf_ops; -#else -/* Dummy declaration for the CATU ops */ -static const struct etr_buf_operations etr_catu_buf_ops; -#endif #endif diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index 2d6f428176ff..3b684687b5a7 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -747,7 +747,8 @@ static inline void tmc_etr_disable_catu(struct tmc_drvdata *drvdata) static const struct etr_buf_operations *etr_buf_ops[] = { [ETR_MODE_FLAT] = &etr_flat_buf_ops, [ETR_MODE_ETR_SG] = &etr_sg_buf_ops, - [ETR_MODE_CATU] = &etr_catu_buf_ops, + [ETR_MODE_CATU] = IS_ENABLED(CONFIG_CORESIGHT_CATU) + ? &etr_catu_buf_ops : NULL, }; static inline int tmc_etr_mode_alloc_buf(int mode, @@ -761,7 +762,7 @@ static inline int tmc_etr_mode_alloc_buf(int mode, case ETR_MODE_FLAT: case ETR_MODE_ETR_SG: case ETR_MODE_CATU: - if (etr_buf_ops[mode]->alloc) + if (etr_buf_ops[mode] && etr_buf_ops[mode]->alloc) rc = etr_buf_ops[mode]->alloc(drvdata, etr_buf, node, pages); if (!rc) -- 2.20.1