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

From: Khadija Kamran <kamrankhadijadj@gmail.com>
To: "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Cc: outreachy@lists.linux.dev,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5] staging: axis-fifo: initialize timeouts in probe only
Date: Thu, 16 Mar 2023 20:09:08 +0500	[thread overview]
Message-ID: <ZBMxFLtW2ekCvm/s@khadija-virtual-machine> (raw)
In-Reply-To: <2626731.BddDVKsqQX@suse>

On Thu, Mar 16, 2023 at 03:38:03PM +0100, Fabio M. De Francesco wrote:
> 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.
>

Hey Fabio!
Thank you for your feedback. I have undertood it and will make sure to
send them in the next PATCH v6.

> 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.
> 

Can you please explain the above feedback. I am confused. What should I
use instead of 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?
>

Sorry, my bad.  Instead of fixing the menuconfig I used this command to
remove the warnings: 
make -j"$(nproc)" ARCH=arm64 LLVM=1 drivers/staging/axis-fifo/
I thought it is compiling my module correctly.
But I am working on your feedback. And before sending my next patch I
will make sure to compile it properly.

> 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
> 
> 
> 
> 