linux-kernel - [PATCH v2 2/4] venus: Limit HFI sessions to the maximum supported

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Message-Id: <20201204100139.6216-3-stanimir.varbanov@linaro.org>
Date:   Fri,  4 Dec 2020 12:01:37 +0200
From:   Stanimir Varbanov <stanimir.varbanov@...aro.org>
To:     linux-media@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     dikshita@...eaurora.org, Alexandre Courbot <acourbot@...omium.org>,
        Vikash Garodia <vgarodia@...eaurora.org>,
        Stanimir Varbanov <stanimir.varbanov@...aro.org>
Subject: [PATCH v2 2/4] venus: Limit HFI sessions to the maximum supported

Currently we rely on firmware to return error when we reach the maximum
supported number of sessions. But this errors are happened at reqbuf
time which is a bit later. The more reasonable way looks like is to
return the error on driver open.

To achieve that modify hfi_session_create to return error when we reach
maximum count of sessions and thus refuse open.

Signed-off-by: Stanimir Varbanov <stanimir.varbanov@...aro.org>
---
 drivers/media/platform/qcom/venus/core.h       |  1 +
 drivers/media/platform/qcom/venus/hfi.c        | 16 +++++++++++++---
 drivers/media/platform/qcom/venus/hfi_parser.c |  3 +++
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/media/platform/qcom/venus/core.h b/drivers/media/platform/qcom/venus/core.h
index f03ed427accd..775d7bf6587d 100644
--- a/drivers/media/platform/qcom/venus/core.h
+++ b/drivers/media/platform/qcom/venus/core.h
@@ -96,6 +96,7 @@ struct venus_format {
 #define MAX_CAP_ENTRIES		32
 #define MAX_ALLOC_MODE_ENTRIES	16
 #define MAX_CODEC_NUM		32
+#define MAX_SESSIONS		16
 
 struct raw_formats {
 	u32 buftype;
diff --git a/drivers/media/platform/qcom/venus/hfi.c b/drivers/media/platform/qcom/venus/hfi.c
index 638ed5cfe05e..8786609d269e 100644
--- a/drivers/media/platform/qcom/venus/hfi.c
+++ b/drivers/media/platform/qcom/venus/hfi.c
@@ -175,6 +175,8 @@ static int wait_session_msg(struct venus_inst *inst)
 int hfi_session_create(struct venus_inst *inst, const struct hfi_inst_ops *ops)
 {
 	struct venus_core *core = inst->core;
+	bool max;
+	int ret;
 
 	if (!ops)
 		return -EINVAL;
@@ -184,11 +186,19 @@ int hfi_session_create(struct venus_inst *inst, const struct hfi_inst_ops *ops)
 	inst->ops = ops;
 
 	mutex_lock(&core->lock);
-	list_add_tail(&inst->list, &core->instances);
-	atomic_inc(&core->insts_count);
+
+	max = atomic_add_unless(&core->insts_count, 1,
+				core->max_sessions_supported);
+	if (!max) {
+		ret = -EAGAIN;
+	} else {
+		list_add_tail(&inst->list, &core->instances);
+		ret = 0;
+	}
+
 	mutex_unlock(&core->lock);
 
-	return 0;
+	return ret;
 }
 EXPORT_SYMBOL_GPL(hfi_session_create);
 
diff --git a/drivers/media/platform/qcom/venus/hfi_parser.c b/drivers/media/platform/qcom/venus/hfi_parser.c
index 363ee2a65453..52898633a8e6 100644
--- a/drivers/media/platform/qcom/venus/hfi_parser.c
+++ b/drivers/media/platform/qcom/venus/hfi_parser.c
@@ -276,6 +276,9 @@ u32 hfi_parser(struct venus_core *core, struct venus_inst *inst, void *buf,
 		words_count--;
 	}
 
+	if (!core->max_sessions_supported)
+		core->max_sessions_supported = MAX_SESSIONS;
+
 	parser_fini(inst, codecs, domain);
 
 	return HFI_ERR_NONE;
-- 
2.17.1