linux-kernel - Re: [PATCH] staging: pi433: add rw semaphore fixing concurrency issues

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Message-ID: <20180601135121.GA11084@hle-laptop.local>
Date:   Fri, 1 Jun 2018 09:51:21 -0400
From:   Hugo Lefeuvre <hle@....eu.com>
To:     valdis.kletnieks@...edu
Cc:     devel@...verdev.osuosl.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org, kernelnewbies@...nelnewbies.org
Subject: Re: [PATCH] staging: pi433: add rw semaphore fixing concurrency
 issues

Hi Valdis,

> > @@ -805,9 +809,11 @@ pi433_read(struct file *filp, char __user *buf, size_t size, loff_t *f_pos)
> >  	if (bytes_received > 0) {
> >  		retval = copy_to_user(buf, device->rx_buffer, bytes_received);
> >  		if (retval)
> > +			up_read(&instance->instance_sem);
> >  			return -EFAULT;
> >  	}
> >
> > +	up_read(&instance->instance_sem);
> >  	return bytes_received;
> >  }
> 
> This doesn't do what you think.

Oh right, no curly braces, didn't notice it. Thanks !

Otherwise, do you think the usage of rw semaphore is appropriate in this
case ?

Regards,
 Hugo

-- 
             Hugo Lefeuvre (hle)    |    www.owl.eu.com
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