On 02/12/2018 10:09 PM, Laura Abbott wrote: > On 02/12/2018 11:21 AM, Alexey Skidanov wrote: >> >> >> On 02/12/2018 08:30 PM, Laura Abbott wrote: >>> On 02/10/2018 01:43 AM, Alexey Skidanov wrote: >>>> Hi, >>>> >>>> Current ion kernel mapping implementation uses vmap() to map previously >>>> allocated buffers into kernel virtual address space. On 32 bit >>>> platforms, vmap() might fail on large enough buffers due to the limited >>>> available vmalloc space. >>>> >>>> dma_buf_kmap() should guarantee that only one page is mapped at a time. >>>> So, probably it's better to implement dma_buf_kmap() by kmap() and not >>>> by vmap()? >>>> >>>> Thanks, >>>> Alexey >>>> >>> >>> The short answer is yes. >>> >>> The long answer is that the conversion to the dma_buf APIs kept the >>> existing Ion behavior which mapped the entire buffer. We got away >>> with this because the in kernel mapping APIs are used very infrequently >>> and with buffers that never triggered an exhaustion of vmalloc >>> space. >>> >>> If we actually start seeing problems with this we can fix it up >>> but I don't consider this a high priority item. >> I have the patch fixing this potential bug. I would like to submit it >> for review, if you are ok with it. Please, just let me know. > > Yes, please submit from review and we can go from there. > Ok. Will submit it. >>> >>> Thanks, >>> Laura >> >> Thanks, >> Alexey >> > Thanks, Alexey _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
