On Tue, Jul 19, 2016 at 12:35:40AM +0200, Michal Suchanek wrote: > config SPI_SPIDEV > - tristate "User mode SPI device driver support" > + bool "User mode SPI device driver support" This is a step back, it would require spidev to be built in. > - spin_lock_irq(&spidev->spi_lock); > - spi = spi_dev_get(spidev->spi); > - spin_unlock_irq(&spidev->spi_lock); > + spi = filp->private_data; > + spi = spi_dev_get(spi); All this refactoring to move spidev about should've been a separate patch, it's hard to find the actual content in here. > - mutex_lock(&device_list_lock); > + dev = bus_find_device(&spi_bus_type, NULL, (void *) inode->i_rdev, > + spidev_devt_match); ... > - dev_dbg(&spidev->spi->dev, "open/ENOMEM\n"); > + spi = to_spi_device(dev); > + > + mutex_lock(&spi->buf_lock); > + spin_lock_irq(&spi->spidev_lock); > + spi->spidev_users++; > + spin_unlock_irq(&spi->spidev_lock); This is broken, it will unconditionally create a spidev for any chip select regardless of if there's any actual hardware there and (even more importantly) regardless if that hardware is actually a SPI device. This is not safe, especially given some of the ideas people seem to have for userspaces. I am getting completely fed up of saying this, it's not OK to just expose pins to userspace when we have no idea what they are connected to.
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