Hi Sergey, On Mon, Apr 17, 2017 at 10:54:29AM +0900, Sergey Senozhatsky wrote: > On (04/17/17 10:21), Sergey Senozhatsky wrote: > > > However, it should be *fixed* to prevent confusion in future > > or may be something like below? can save us some cycles. > > remove this calculation > > - offset = sector & (SECTORS_PER_PAGE - 1) << SECTOR_SHIFT; > > > and pass 0 to zram_bvec_rw() > > - err = zram_bvec_rw(zram, &bv, index, offset, is_write); > + err = zram_bvec_rw(zram, &bv, index, 0, is_write); That was one I wrote but have thought it more. Because I suspect fs can submit page-size IO in non-aligned PAGE_SIZE sector? For example, it can submit PAGE_SIZE read request from 9 sector. Is it possible? I don't know. As well, FS can format zram from sector 1, not sector 0? IOW, can't it use starting sector as non-page algined sector? We can do it via fdisk? Anyway, If one of scenario I mentioned is possible, zram_rw_page will be broken. If it's hard to check all of scenario in this moment, it would be better to not remove it and then add WARN_ON(offset) in there. While I am writing this, I found this. /** * bdev_read_page() - Start reading a page from a block device * @bdev: The device to read the page from * @sector: The offset on the device to read the page to (need not be aligned) * @page: The page to read * Hmm,, need investigation but no time.