2023-07-31 05:34:22

by Bjorn Andersson

Subject: [PATCH 3/4] soc: qcom: aoss: Format string in qmp_send()

The majority of callers to qmp_send() composes the message dynamically
using some form of sprintf(), resulting in unnecessary complication and
stack usage.

By changing the interface of qmp_send() to take a format string and
arguments, the duplicated composition of the commands can be moved to a
single location.

Signed-off-by: Bjorn Andersson <[email protected]>
---
drivers/soc/qcom/qcom_aoss.c | 22 ++++++++++++++--------
include/linux/soc/qcom/qcom_aoss.h | 4 ++--
2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/drivers/soc/qcom/qcom_aoss.c b/drivers/soc/qcom/qcom_aoss.c
index 4c5bb7034fff..b59c8681bcfe 100644
--- a/drivers/soc/qcom/qcom_aoss.c
+++ b/drivers/soc/qcom/qcom_aoss.c
@@ -207,27 +207,33 @@ static bool qmp_message_empty(struct qmp *qmp)
/**
* qmp_send() - send a message to the AOSS
* @qmp: qmp context
- * @data: message to be sent
+ * @fmt: format string for message to be sent
+ * @...: arguments for the format string
*
- * Transmit @data to AOSS and wait for the AOSS to acknowledge the message.
+ * Transmit message to AOSS and wait for the AOSS to acknowledge the message.
* data must not be longer than the mailbox size. Access is synchronized by
* this implementation.
*
* Return: 0 on success, negative errno on failure
*/
-int qmp_send(struct qmp *qmp, const void *data)
+int qmp_send(struct qmp *qmp, const char *fmt, ...)
{
long time_left;
+ va_list args;
char buf[QMP_MSG_LEN];
+ int len;
int ret;

- if (WARN_ON(IS_ERR_OR_NULL(qmp) || !data))
+ if (WARN_ON(IS_ERR_OR_NULL(qmp) || !fmt))
return -EINVAL;

- if (WARN_ON(strlen(data) >= sizeof(buf)))
- return -EINVAL;
+ memset(buf, 0, sizeof(buf));
+ va_start(args, fmt);
+ len = vsnprintf(buf, sizeof(buf), fmt, args);
+ va_end(args);

- strscpy_pad(buf, data, sizeof(buf));
+ if (WARN_ON(len >= sizeof(buf)))
+ return -EINVAL;

mutex_lock(&qmp->tx_lock);

@@ -491,7 +497,7 @@ static ssize_t qmp_debugfs_write(struct file *file, const char __user *userstr,
return -EFAULT;
buf[len] = '\0';

- ret = qmp_send(qmp, buf);
+ ret = qmp_send(qmp, "%s", buf);
if (ret < 0)
return ret;

diff --git a/include/linux/soc/qcom/qcom_aoss.h b/include/linux/soc/qcom/qcom_aoss.h
index 7a71406b6050..7361ca028752 100644
--- a/include/linux/soc/qcom/qcom_aoss.h
+++ b/include/linux/soc/qcom/qcom_aoss.h
@@ -13,13 +13,13 @@ struct qmp;

#if IS_ENABLED(CONFIG_QCOM_AOSS_QMP)

-int qmp_send(struct qmp *qmp, const void *data);
+int qmp_send(struct qmp *qmp, const char *fmt, ...);
struct qmp *qmp_get(struct device *dev);
void qmp_put(struct qmp *qmp);

#else

-static inline int qmp_send(struct qmp *qmp, const void *data)
+static inline int qmp_send(struct qmp *qmp, const char *fmt, ...)
{
return -ENODEV;
}
--
2.25.1

2023-07-31 09:46:15

by Konrad Dybcio

Subject: Re: [PATCH 3/4] soc: qcom: aoss: Format string in qmp_send()

On 31.07.2023 06:10, Bjorn Andersson wrote:
> The majority of callers to qmp_send() composes the message dynamically
> using some form of sprintf(), resulting in unnecessary complication and
> stack usage.
>
> By changing the interface of qmp_send() to take a format string and
> arguments, the duplicated composition of the commands can be moved to a
> single location.
>
> Signed-off-by: Bjorn Andersson <[email protected]>
> ---
[...]


> +int qmp_send(struct qmp *qmp, const char *fmt, ...)
> {
> long time_left;
> + va_list args;
> char buf[QMP_MSG_LEN];
> + int len;
> int ret;
>
> - if (WARN_ON(IS_ERR_OR_NULL(qmp) || !data))
> + if (WARN_ON(IS_ERR_OR_NULL(qmp) || !fmt))
> return -EINVAL;
>
> - if (WARN_ON(strlen(data) >= sizeof(buf)))
> - return -EINVAL;
> + memset(buf, 0, sizeof(buf));
Wouldn't initializing the array with = { 0 } be faster?

Otherwise, this looks very cool

Reviewed-by: Konrad Dybcio <[email protected]>

Konrad