[dm-devel] split scsi passthrough fields out of struct request V2

[Bart Van Assche]

On Mon, 2017-01-30 at 17:38 -0800, Jens Axboe wrote:
> That's a known bug in mainline. Pull it into 4.10-rc6,
> or use my for-next where everything is already merged. 

Hello Jens,

With your for-next branch (commit c2e60b3a2602) I haven't hit any block
layer crashes so far. The only issue I encountered that is new is a
memory leak triggered by the SG-IO code. These memory leak reports
started to appear after I started testing the mq-deadline scheduler.
kmemleak reported the following call stack multiple times after my tests
had finished:

unreferenced object 0xffff88041119e528 (size 192):
  comm "multipathd", pid 2353, jiffies 4295128020 (age 1332.440s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 12 01 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff8165e3b5>] kmemleak_alloc+0x45/0xa0
    [<ffffffff811cc23d>] __kmalloc+0x15d/0x2f0
    [<ffffffff81310e35>] bio_alloc_bioset+0x185/0x1f0
    [<ffffffff813117f4>] bio_map_user_iov+0x124/0x400
    [<ffffffff81320b7a>] blk_rq_map_user_iov+0x11a/0x210
    [<ffffffff81320cbd>] blk_rq_map_user+0x4d/0x60
    [<ffffffff81336694>] sg_io+0x3d4/0x410
    [<ffffffff813369d0>] scsi_cmd_ioctl+0x300/0x490
    [<ffffffff81336b9d>] scsi_cmd_blk_ioctl+0x3d/0x50
    [<ffffffff814b4360>] sd_ioctl+0x80/0x100
    [<ffffffff8132ddde>] blkdev_ioctl+0x51e/0x9f0
    [<ffffffff8122f388>] block_ioctl+0x38/0x40
    [<ffffffff8120097f>] do_vfs_ioctl+0x8f/0x700
    [<ffffffff8120102c>] SyS_ioctl+0x3c/0x70
    [<ffffffff8166c4aa>] entry_SYSCALL_64_fastpath+0x18/0xad

Bart.