2011/3/20 John Calixto <john.cali...@modsystems.com>: > On Sat, 19 Mar 2011, Arnd Bergmann wrote: [...] >> > I expect for more general purposes, like your qemu passthrough case, you >> > would want to add a handler for cmd=SD_IOC_CMD? >> Yes, but I suspect that would mean blocking all other activity on the >> same device, possibly with an ioctl for claiming the host for an >> extended period of time. > Sure. And if the testing I described above shows that regular block > operations are indeed negatively affected, then I'll have to implement > that ioctl for claiming the host myself and you'll have a head start! :)
This idea is scary. ;-) Just think what would happen if userspace made this sequence: 1. fd = open(dev) 2. ioctl(fd, claim host) 3. read(fd, ...) (if 3. is not convincing, replace it with any access to mounted filesystem from the same card.) Best Regards, Michał Mirosław -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
