Re: [PATCH v5] staging: axis-fifo: initialize timeouts in probe only

["Fabio M. De Francesco" <fmdefrancesco@gmail.com>]

Khadija,

Just saw your v5 patch and Greg's two replies.

For v6 you will need to change the subject to "[PATCH v6] staging: axis-fifo: 
initialize timeouts in init only" to indicate that you are doing assignments 
in axis_fifo_init().

Don't forget to extend the version log with "Changes in v6:" and clarify that 
v5 had a different "Object" (you should probably also add a link to the v5 
patch in lore: https://lore.kernel.org/lkml /ZBMR4s8xyHGqMm72@khadija-virtual-
machine/). When the "Subject" changes, readers may not find the previous 
versions easily.    

On giovedì 16 marzo 2023 13:56:02 CET Khadija Kamran wrote:
> Module parameter, read_timeout, can only be set at the loading time. As
> it can only be modified once, initialize read_timeout once in the probe

Substitute "probe" with "init".

> function.
> 
> As a result, only use read_timeout as the last argument in
> wait_event_interruptible_timeout() call.

This two sentences are not much clear. I'd merge and rework:

"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 datatpe

s/datatpe/type/

> of read_timeout

of {read,write}_timeout

> from 'int' to 'long int' because
> implicit conversion of 'long int' to 'int' in statement 'read_timeout =
> MAX_SCHEDULE_TIMEOUT' results in an overflow warning.

We don't care too much about the warning themselves: I mean, it overflows and 
you must avoid it to happen (as you are doing with the changes of types), not 
merely be interested in avoiding the warning. "[] results in an overflow." is 
all we care about.

Add also the previous paragraph in the last part of the commit message.
 
> Perform same steps formodule parameter, write_timeout.

And instead delete the this last phrase.

> Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Khadija Kamran <kamrankhadijadj@gmail.com>
> ---
> 
> Changes in v5:
>  - Convert timeout's datatype from int to long.
> Changes in v4:
>  - Initialize timeouts once as suggested by Greg; this automatically
>    fixes the indentation problems.
>  - Change the subject and description.
> Changes in v3:
>  - Fix 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 instead.
>  - Change the subject to 'remove tabs to align arguments'.
>  - Use imperative language in subject and description
> 
>  drivers/staging/axis-fifo/axis-fifo.c | 26 ++++++++++++++++----------
>  1 file changed, 16 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/staging/axis-fifo/axis-fifo.c
> b/drivers/staging/axis-fifo/axis-fifo.c index dfd2b357f484..d667dc80df47
> 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,

What is this? You haven't yet compiled your patch.
Any further problems with enabling axis-fifo as a module?

Fabio

> 
> -				 (write_timeout >= 0) ?
> -				  msecs_to_jiffies(write_timeout) :
> -				  MAX_SCHEDULE_TIMEOUT);
> +			write_timeout);
> 
>  		if (ret <= 0) {
>  			if (ret == 0) {
> @@ -815,6 +811,16 @@ static int axis_fifo_probe(struct platform_device 
*pdev)
>  	char *device_name;
>  	int rc = 0; /* error return value */
> 
> +	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;
> +
>  	/* ----------------------------
>  	 *     init wrapper device
>  	 * ----------------------------
> --
> 2.34.1