On Wed, Sep 24, 2014 at 01:00:02PM +0100, Lee Jones wrote: > On Wed, 24 Sep 2014, Johan Hovold wrote: > > > On Wed, Sep 24, 2014 at 11:12:06AM +0100, Lee Jones wrote: > > > On Mon, 22 Sep 2014, Octavian Purdila wrote: > > > > > > > Currently the I/O buffer is allocated part of the device status > > > > structure, potentially sharing the same cache line with other members > > > > in this structure. > > > > > > > > Allocate the buffer separately, to avoid the I/O operations corrupting > > > > the device status structure due to cache line sharing. > > > > > > > > Compiled tested only as I don't have access to hardware. > > > > > > > > Signed-off-by: Octavian Purdila <octavian.purdila@xxxxxxxxx> > > > > --- > > > > drivers/mfd/viperboard.c | 8 ++++++++ > > > > include/linux/mfd/viperboard.h | 2 +- > > > > 2 files changed, 9 insertions(+), 1 deletion(-) > > > > > > > > diff --git a/drivers/mfd/viperboard.c b/drivers/mfd/viperboard.c > > > > index e00f534..5f62f4e 100644 > > > > --- a/drivers/mfd/viperboard.c > > > > +++ b/drivers/mfd/viperboard.c > > > > @@ -64,6 +64,12 @@ static int vprbrd_probe(struct usb_interface *interface, > > > > return -ENOMEM; > > > > } > > > > > > > > + vb->buf = kzalloc(sizeof(struct vprbrd_i2c_write_msg), GFP_KERNEL); > > > > > > Can you obtain the 'struct device' first then use managed resources > > > (devm_*)? > > > > I think any devres conversion should be done in a follow-up patch and > > not be included in the fix (e.g. in order to facilitate backporting). We > > also don't want to mix allocation schemes. > > I agree, but equally I'm not keen on accepting this patch as I believe > it could be done better. > > Please submit two patches, one converting to shared resources and this > being the subsequent one, fixed up to do the right thing. A buffer-corruption fix is a candidate for stable, whereas a devres conversion (clean up) is not. Hence the former should not depend on the latter. Johan -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
