Re: [PATCH v6] staging: axis-fifo: initialize timeouts in init only

[Fabio M. De Francesco]

On giovedì 16 marzo 2023 17:26:15 CET Khadija Kamran wrote:
> Initialize the module parameters, read_timeout and write_timeout once in
> init().
> 
> Module parameters can only be set once and cannot be modified later, so we
> don't need to evaluate them again when passing the parameters to
> wait_event_interruptible_timeout().
> 
> Convert datatype of {read,write}_timeout from 'int' to 'long int' because
> implicit conversion of 'long int' to 'int' in statement
> '{read,write}_timeout = MAX_SCHEDULE_TIMEOUT' results in an overflow.
> 
> Change format specifier for {read,write}_timeout from %i to %li.

It's good that you added this line. I had missed it :-)

> Suggested-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Khadija Kamran <kamrankhadijadj@xxxxxxxxx>
> ---
> 
> Changes in v6:
>  - Initialize module parameters in init instead of probe function.
>  - Change the subject and description
>  - Change format specifiers of module parameters to "%li"
> 
> Changes in v5:
>  - Convert module parameters's datatype from int to long.

NIT: "parameters'", not "parameters's".

>  - Link to patch:
>  https://lore.kernel.org/outreachy/ZBMR4s8xyHGqMm72@khadija-virtual-machine/
> 
> Changes in v4:
>  - Initialize timeouts once as suggested by Greg; this automatically
>    fixes the indentation problems.
>  - Change the subject and description.
>  - Link to patch:
>  https://lore.kernel.org/outreachy/ZA4M3+ZeB1Rl2fbs@khadija-virtual-machine/
> 
> Changes in v3:
>  - Correct grammatical mistakes
>  - Do not change the second argument's indentation in split lines
> 
> Changes in v2:
>  - Instead of matching alignment to open parenthesis, align second and
>    the last argument.
>  - Change the subject and use imperative language.
>  - Link to patch:
>  https://lore.kernel.org/outreachy/ZAxNYw2rFQkrdtKl@khadija-virtual-machine/
> 
> Link to first patch:
>  https://lore.kernel.org/outreachy/ZAZSmPpB6fcozGa4@khadija-virtual-machine/
> 
> drivers/staging/axis-fifo/axis-fifo.c | 28 ++++++++++++++++-----------
>  1 file changed, 17 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/staging/axis-fifo/axis-fifo.c
> b/drivers/staging/axis-fifo/axis-fifo.c index dfd2b357f484..0a85ea667a1b
> 100644
> --- a/drivers/staging/axis-fifo/axis-fifo.c
> +++ b/drivers/staging/axis-fifo/axis-fifo.c
> @@ -103,17 +103,17 @@
>   *           globals
>   * ----------------------------
>   */
> -static int read_timeout = 1000; /* ms to wait before read() times out */
> -static int write_timeout = 1000; /* ms to wait before write() times out */
> +static long read_timeout = 1000; /* ms to wait before read() times out */
> +static long write_timeout = 1000; /* ms to wait before write() times out */
> 
>  /* ----------------------------
>   * module command-line arguments
>   * ----------------------------
>   */
> 
> -module_param(read_timeout, int, 0444);
> +module_param(read_timeout, long, 0444);
>  MODULE_PARM_DESC(read_timeout, "ms to wait before blocking read() timing 
out;
> set to -1 for no timeout"); -module_param(write_timeout, int, 0444);
> +module_param(write_timeout, long, 0444);
>  MODULE_PARM_DESC(write_timeout, "ms to wait before blocking write() timing
> out; set to -1 for no timeout");
> 
>  /* ----------------------------
> @@ -384,9 +384,7 @@ static ssize_t axis_fifo_read(struct file *f, char 
__user
> *buf, mutex_lock(&fifo->read_lock);
>  		ret = wait_event_interruptible_timeout(fifo->read_queue,
>  			ioread32(fifo->base_addr + XLLF_RDFO_OFFSET),
> -				 (read_timeout >= 0) ?
> -				  msecs_to_jiffies(read_timeout) :
> -				  MAX_SCHEDULE_TIMEOUT);
> +			read_timeout);
> 
>  		if (ret <= 0) {
>  			if (ret == 0) {
> @@ -528,9 +526,7 @@ static ssize_t axis_fifo_write(struct file *f, const 
char
> __user *buf, ret = wait_event_interruptible_timeout(fifo->write_queue,
>  			ioread32(fifo->base_addr + XLLF_TDFV_OFFSET)
> 
>  				 >= words_to_write,

NIT: I don't really like this split of the second argument into two lines. 
This line may look too long, but I don't think that it should be split. I 
prefer to read 

"ioread32(fifo->base_addr + XLLF_TDFV_OFFSET) >= words_to_write,"

However, the final decision is up to Greg.

If he takes the code as is, I have nothing against. 
Don't send any other version unless required by Greg or other Mentors with 
more experience than I have.

All the rest look good... well done!

Reviewed-by: Fabio M. De Francesco

Please feel free to forward my tag if you are required to change that line and 
send a new version.

Thanks,

Fabio

> -				 (write_timeout >= 0) ?
> -				  msecs_to_jiffies(write_timeout) :
> -				  MAX_SCHEDULE_TIMEOUT);
> +			write_timeout);
> 
>  		if (ret <= 0) {
>  			if (ret == 0) {
> @@ -948,7 +944,17 @@ static struct platform_driver axis_fifo_driver = {
> 
>  static int __init axis_fifo_init(void)
>  {
> -	pr_info("axis-fifo driver loaded with parameters read_timeout = %i,
> write_timeout = %i\n", +	if (read_timeout >= 0)
> +		read_timeout = msecs_to_jiffies(read_timeout);
> +	else
> +		read_timeout = MAX_SCHEDULE_TIMEOUT;
> +
> +	if (write_timeout >= 0)
> +		write_timeout = msecs_to_jiffies(write_timeout);
> +	else
> +		write_timeout = MAX_SCHEDULE_TIMEOUT;
> +
> +	pr_info("axis-fifo driver loaded with parameters read_timeout = %li,
> write_timeout = %li\n", read_timeout, write_timeout);
>  	return platform_driver_register(&axis_fifo_driver);
>  }
> --
> 2.34.1