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Date:   Wed, 22 Jul 2020 12:41:28 +0200
From:   Wolfram Sang <wsa@kernel.org>
To:     Ray Jui <ray.jui@broadcom.com>
Cc:     Dhananjay Phadke <dphadke@linux.microsoft.com>,
        Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com>,
        linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
        Ray Jui <rjui@broadcom.com>,
        bcm-kernel-feedback-list@broadcom.com
Subject: Re: [PATCH] i2c: iproc: fix race between client unreg and isr
Message-ID: <20200722104128.GK1030@ninjato>
References: <1595115599-100054-1-git-send-email-dphadke@linux.microsoft.com>
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> > +	synchronize_irq(iproc_i2c->irq);
>=20
> If one takes a look at the I2C slave ISR routine, there are places where
> IRQ can be re-enabled in the ISR itself. What happens after we mask all
> slave interrupt and when 'synchronize_irq' is called, which I suppose is
> meant to wait for inflight interrupt to finish where there's a chance
> the interrupt can be re-enable again? How is one supposed to deal with th=
at?

I encountered the same problem with the i2c-rcar driver before I left
for my holidays.

> > +	iproc_i2c->slave =3D NULL;
> > +
> >  	/* Erase the slave address programmed */
> >  	tmp =3D iproc_i2c_rd_reg(iproc_i2c, S_CFG_SMBUS_ADDR_OFFSET);
> >  	tmp &=3D ~BIT(S_CFG_EN_NIC_SMB_ADDR3_SHIFT);
> >=20

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