From 5aec7c065fba0c56d6c1ea5d629395210f174be8 Mon Sep 17 00:00:00 2001 From: James Clark Date: Thu, 28 Nov 2024 12:14:14 +0000 Subject: [PATCH] coresight: Drop atomics in connection refcounts These belong to the device being enabled or disabled and are only ever used inside the device's spinlock. Remove the atomics to not imply that there are any other concurrent accesses. If atomics were necessary I don't think they would have been enough anyway. There would be nothing to prevent an enable or disable running concurrently if not for the spinlock. Signed-off-by: James Clark Reviewed-by: Yeoreum Yun Signed-off-by: Suzuki K Poulose Link: https://lore.kernel.org/r/20241128121414.2425119-1-james.clark@linaro.org --- drivers/hwtracing/coresight/coresight-funnel.c | 6 +++--- drivers/hwtracing/coresight/coresight-replicator.c | 6 +++--- drivers/hwtracing/coresight/coresight-tpda.c | 6 +++--- include/linux/coresight.h | 4 ++-- 4 files changed, 11 insertions(+), 11 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-funnel.c b/drivers/hwtracing/coresight/coresight-funnel.c index 33efe1acbef7..8faf51469bb8 100644 --- a/drivers/hwtracing/coresight/coresight-funnel.c +++ b/drivers/hwtracing/coresight/coresight-funnel.c @@ -86,14 +86,14 @@ static int funnel_enable(struct coresight_device *csdev, bool first_enable = false; spin_lock_irqsave(&drvdata->spinlock, flags); - if (atomic_read(&in->dest_refcnt) == 0) { + if (in->dest_refcnt == 0) { if (drvdata->base) rc = dynamic_funnel_enable_hw(drvdata, in->dest_port); if (!rc) first_enable = true; } if (!rc) - atomic_inc(&in->dest_refcnt); + in->dest_refcnt++; spin_unlock_irqrestore(&drvdata->spinlock, flags); if (first_enable) @@ -130,7 +130,7 @@ static void funnel_disable(struct coresight_device *csdev, bool last_disable = false; spin_lock_irqsave(&drvdata->spinlock, flags); - if (atomic_dec_return(&in->dest_refcnt) == 0) { + if (--in->dest_refcnt == 0) { if (drvdata->base) dynamic_funnel_disable_hw(drvdata, in->dest_port); last_disable = true; diff --git a/drivers/hwtracing/coresight/coresight-replicator.c b/drivers/hwtracing/coresight/coresight-replicator.c index 0fba87de6d1a..a1181c9048c0 100644 --- a/drivers/hwtracing/coresight/coresight-replicator.c +++ b/drivers/hwtracing/coresight/coresight-replicator.c @@ -126,7 +126,7 @@ static int replicator_enable(struct coresight_device *csdev, bool first_enable = false; spin_lock_irqsave(&drvdata->spinlock, flags); - if (atomic_read(&out->src_refcnt) == 0) { + if (out->src_refcnt == 0) { if (drvdata->base) rc = dynamic_replicator_enable(drvdata, in->dest_port, out->src_port); @@ -134,7 +134,7 @@ static int replicator_enable(struct coresight_device *csdev, first_enable = true; } if (!rc) - atomic_inc(&out->src_refcnt); + out->src_refcnt++; spin_unlock_irqrestore(&drvdata->spinlock, flags); if (first_enable) @@ -180,7 +180,7 @@ static void replicator_disable(struct coresight_device *csdev, bool last_disable = false; spin_lock_irqsave(&drvdata->spinlock, flags); - if (atomic_dec_return(&out->src_refcnt) == 0) { + if (--out->src_refcnt == 0) { if (drvdata->base) dynamic_replicator_disable(drvdata, in->dest_port, out->src_port); diff --git a/drivers/hwtracing/coresight/coresight-tpda.c b/drivers/hwtracing/coresight/coresight-tpda.c index bfca103f9f84..4ec676bea1ce 100644 --- a/drivers/hwtracing/coresight/coresight-tpda.c +++ b/drivers/hwtracing/coresight/coresight-tpda.c @@ -190,10 +190,10 @@ static int tpda_enable(struct coresight_device *csdev, int ret = 0; spin_lock(&drvdata->spinlock); - if (atomic_read(&in->dest_refcnt) == 0) { + if (in->dest_refcnt == 0) { ret = __tpda_enable(drvdata, in->dest_port); if (!ret) { - atomic_inc(&in->dest_refcnt); + in->dest_refcnt++; csdev->refcnt++; dev_dbg(drvdata->dev, "TPDA inport %d enabled.\n", in->dest_port); } @@ -223,7 +223,7 @@ static void tpda_disable(struct coresight_device *csdev, struct tpda_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); spin_lock(&drvdata->spinlock); - if (atomic_dec_return(&in->dest_refcnt) == 0) { + if (--in->dest_refcnt == 0) { __tpda_disable(drvdata, in->dest_port); csdev->refcnt--; } diff --git a/include/linux/coresight.h b/include/linux/coresight.h index c13342594278..834029cb9ba2 100644 --- a/include/linux/coresight.h +++ b/include/linux/coresight.h @@ -200,8 +200,8 @@ struct coresight_connection { struct coresight_device *dest_dev; struct coresight_sysfs_link *link; struct coresight_device *src_dev; - atomic_t src_refcnt; - atomic_t dest_refcnt; + int src_refcnt; + int dest_refcnt; }; /**