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

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Date:   Thu, 16 Mar 2023 20:06:55 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     "Fabio M. De Francesco" <fmdefrancesco@...il.com>
Cc:     outreachy@...ts.linux.dev,
        Khadija Kamran <kamrankhadijadj@...il.com>,
        linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6] staging: axis-fifo: initialize timeouts in init only

On Thu, Mar 16, 2023 at 07:11:09PM +0100, Fabio M. De Francesco wrote:
> 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@...uxfoundation.org>
> > Signed-off-by: Khadija Kamran <kamrankhadijadj@...il.com>
> > ---
> > 
> > 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.

That's not the change that is happening here, so it can be done in a
follow-on patch if you so desire.

> 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

This will not work, sorry, please respond with a correct tag (hint, you
forgot your email...)

thanks,

greg k-h