Stefan Richter wrote: > On Sep 10 Shuah Khan wrote: >>>> http://linuxdriverproject.org/mediawiki/index.php/DMA_Mapping_Error_Analysis >>> >>>> File Name # of calls Status >>>> drivers/firewire/core-iso.c 1 Unmap Broken >>>> drivers/firewire/ohci.c 1 Unmap Broken >>> >>> In ohci.c, ar_context_release() takes care of cleanup. >>> >>> In core-iso.c, on failure, the callers are responsible to call >>> fw_iso_buffer_destroy() eventually. (ioctl_create_iso_context() >>> doesn't do this correctly if it's called multiple times.) >> >> Thanks. I updated the page with your comments. I moved ohci.c to Good >> status and left core-iso.c in Unmap Broken in case >> ioctl_create_iso_context() case is worth fixing. > > I don't see what could go wrong if ioctl_create_iso_context() is called > multiple times.
fw_iso_buffer_map_dma() maps as many pages as it can, and saves in ->page_count_mapped how many pages need unmapping. When fw_iso_buffer_map_dma() fails, ioctl_create_iso_context() does _not_ call fw_iso_buffer_destroy() but takes care to not change the cdev's state in any other way. So ioctl_create_iso_context() can be called again and will then call fw_iso_buffer_map_dma(), which will happily map the pages a second time, overwriting the previous mapped addresses. Regards, Clemens -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
