linux-kernel - Re: [PATCH v3] staging: pi433: add debugfs interface

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Date:   Mon, 31 Jan 2022 16:45:58 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Paulo Miguel Almeida <paulo.miguel.almeida.rodenas@...il.com>
Cc:     gregkh@...uxfoundation.org, realwakka@...il.com,
        linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] staging: pi433: add debugfs interface

On Sun, Jan 30, 2022 at 03:57:26PM +1300, Paulo Miguel Almeida wrote:
> @@ -1102,12 +1104,75 @@ static const struct file_operations pi433_fops = {
>  	.llseek =	no_llseek,
>  };
>  
> +static int pi433_debugfs_regs_show(struct seq_file *m, void *p)
> +{
> +	struct pi433_device *dev;
> +	u8 reg_data[114];
> +	int i;
> +	char *fmt = "0x%02x, 0x%02x\n";
> +	int ret = 0;

No need to initialize.  Bogus initializers just disable ten thousand
person hours spent developing static analysis.

> +
> +	dev = m->private;
> +
> +	mutex_lock(&dev->tx_fifo_lock);
> +	mutex_lock(&dev->rx_lock);
> +
> +	// wait for on-going operations to finish
> +	ret = wait_event_interruptible(dev->rx_wait_queue, !dev->tx_active);
> +	if (ret)
> +		return ret;

Drop the two mutexes before returning.

> +
> +	ret = wait_event_interruptible(dev->tx_wait_queue, !dev->rx_active);
> +	if (ret)
> +		return ret;

Drop the mutexes.

> +
> +	// skip FIFO register (0x0) otherwise this can affect some of uC ops
> +	for (i = 1; i < 0x50; i++)
> +		reg_data[i] = rf69_read_reg(dev->spi, i);
> +
> +	reg_data[REG_TESTLNA] = rf69_read_reg(dev->spi, REG_TESTLNA);
> +	reg_data[REG_TESTPA1] = rf69_read_reg(dev->spi, REG_TESTPA1);
> +	reg_data[REG_TESTPA2] = rf69_read_reg(dev->spi, REG_TESTPA2);
> +	reg_data[REG_TESTDAGC] = rf69_read_reg(dev->spi, REG_TESTDAGC);
> +	reg_data[REG_TESTAFC] = rf69_read_reg(dev->spi, REG_TESTAFC);
> +
> +	seq_puts(m, "# reg, val\n");
> +
> +	for (i = 1; i < 0x50; i++)
> +		seq_printf(m, fmt, i, reg_data[i]);
> +
> +	seq_printf(m, fmt, REG_TESTLNA, reg_data[REG_TESTLNA]);
> +	seq_printf(m, fmt, REG_TESTPA1, reg_data[REG_TESTPA1]);
> +	seq_printf(m, fmt, REG_TESTPA2, reg_data[REG_TESTPA2]);
> +	seq_printf(m, fmt, REG_TESTDAGC, reg_data[REG_TESTDAGC]);
> +	seq_printf(m, fmt, REG_TESTAFC, reg_data[REG_TESTAFC]);
> +
> +	mutex_unlock(&dev->rx_lock);
> +	mutex_unlock(&dev->tx_fifo_lock);
> +
> +	return ret;
> +}

regards,
dan carpenter