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From: Varsha Rao <rvarsha016@gmail.com>
To: outreachy-kernel <outreachy-kernel@googlegroups.com>
Cc: rvarsha016@gmail.com, Michael.Hennerich@analog.com,
	jic23@kernel.org, knaack.h@gmx.de, pmeerw@pmeerw.net,
	gregkh@linuxfoundation.org, 21cnbao@gmail.com,
	linux-iio@vger.kernel.org, lars@metafoo.de
Subject: Re: [PATCH 1/2] staging: iio: adis16240: Replace mlock with driver private lock.
Date: Mon, 13 Mar 2017 07:39:41 -0700 (PDT)	[thread overview]
Message-ID: <677299aa-1a1c-412c-85cf-b9117be3e4be@googlegroups.com> (raw)
In-Reply-To: <45f0ef85-3753-946f-4956-6cba4e8a6859@metafoo.de>


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> > +++ b/drivers/staging/iio/accel/adis16240.c 
> > @@ -229,11 +229,12 @@ static ssize_t adis16240_read_12bit_signed(struct 
> device *dev, 
> >  { 
> >          ssize_t ret; 
> >          struct iio_dev *indio_dev = dev_to_iio_dev(dev); 
> > +        struct adis *st = iio_priv(indio_dev); 
> >   
> >          /* Take the iio_dev status lock */ 
> > -        mutex_lock(&indio_dev->mlock); 
> > +        mutex_lock(&st->txrx_lock); 
>
> This unfortunately wont work. The adis_read_reg()/adis_write_reg() 
> functions 
> take the txrx_lock. So this change causes a deadlock, trying to take a 
> lock 
> that is already locked. 
>
>    Yes, it would cause deadlock. Can the lock be placed within the 
   adis_read_reg() function and removing locks from other place?
 

> But this lock can probably be removed. It should be safe to run the 
> function 
> multiple times in parallel. 
>
> Same for the other changes in this patch. 
>
   
   Then should I remove all the locks in this file?
    
   Thanks,
   Varsha

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  reply	other threads:[~2017-03-13 14:39 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <cover.1489395260.git.rvarsha016@gmail.com>
2017-03-13  9:23 ` [PATCH 1/2] staging: iio: adis16240: Replace mlock with driver private lock Varsha Rao
2017-03-13 11:47   ` Lars-Peter Clausen
2017-03-13 14:39     ` Varsha Rao [this message]
2017-03-13  9:23 ` [PATCH 2/2] staging: iio: adis16240: Modify existing comment Varsha Rao
2017-03-13 11:39   ` Lars-Peter Clausen

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