Hi Mikulas, On 11/11/2009 11:05 AM +0900, Mikulas Patocka wrote: > Use low pointer bits for dm io region > > We need to store two things per bio: the pointer to the main io structure and > a region number, an index of disk where this bio belongs to (if there is > simultaneous write to multiple disks). There can be at most BITS_PER_LONG > regions. BITS_PER_LONG is 32 on 32-bit machines and 64 on 64-bit machines. > > A region number was stored in the last hidden bio vector and the pointer to > struct io was stored in bi_private. > > This patch changes it so that "struct io" is always aligned on BITS_PER_LONG > bytes and region number is stored in the low BITS_PER_LONG bits of bi_private. The code is not easily readable for me. Why don't you introduce a new structure in which those two things can be stored, and allocate/attach it per bio? If it's possible, the code should be easy to read and maintain, I think. Thanks, Kiyoshi Ueda -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
