Hi all, Sorry to send this email to you all. I recently noticed there're some incompatibilities existing in the generic_file_splice_read() function between 3.X and 4.X kernel. The result will goes wrong if we're using sendfile() with unaligned offset in 4.X/5.X kernel. But if we do the same in 3.X kernel, it will surely return success. Here is the call trace: 1. Using sendfile() with unaligned offset 2. Then it runs into the kernel: sendfile64()->do_sendfile()->do_splice_direct()->splice_direct_to_actor()->do_splice_to()->splice_read() 3. splice_read() calls the __generic_file_splice_read() in 3.X kernel, generic_file_splice_read() in 4.X kernel. In 3.X kernel, this function handles the alignment by using the PAGE_SHIFT and PAGE_MASK. However, after applying this commit(82c156f853840645604acd7c2cebcb75ed1b6652) the 4.X no longer supports the unaligned data. I'm wondering should we add the alignment process code back again? Does anyone have idea about why this part got removed? Any information and suggestions are welcome:-) Thanks, Jason
