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Commit c77fba9a authored by Rusty Russell's avatar Rusty Russell
Browse files

virtio_scsi: don't call virtqueue_add_sgs(... GFP_NOIO) holding spinlock. 



This triggers every time we do a SCSI abort:

virtscsi_tmf -> virtscsi_kick_cmd (grab lock and call) -> virtscsi_add_cmd
	-> virtqueue_add_sgs (GFP_NOIO)

Logs look like this:
 sd 0:0:0:0: [sda] abort
 BUG: sleeping function called from invalid context at mm/slub.c:966
 in_atomic(): 1, irqs_disabled(): 1, pid: 6, name: kworker/u2:0
 3 locks held by kworker/u2:0/6:
  #0:  ("scsi_tmf_%d"shost->host_no){......}, at: [<c0153180>] process_one_work+0xe0/0x3d0
  #1:  ((&(&cmd->abort_work)->work)){......}, at: [<c0153180>] process_one_work+0xe0/0x3d0
  #2:  (&(&virtscsi_vq->vq_lock)->rlock){......}, at: [<c043f508>] virtscsi_kick_cmd+0x18/0x1b0
 CPU: 0 PID: 6 Comm: kworker/u2:0 Not tainted 3.15.0-rc5+ #110
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-rc1-0-gb1d4dc9-20140515_140003-nilsson.home.kraxel.org 04/01/2014
 Workqueue: scsi_tmf_0 scmd_eh_abort_handler

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Acked-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent a17597d3

drivers/scsi/virtio_scsi.c

+6 −9
Original line number Diff line number Diff line
@@ -433,11 +433,10 @@ static void virtscsi_event_done(struct virtqueue *vq) 
 * @cmd		: command structure

 * @req_size	: size of the request buffer

 * @resp_size	: size of the response buffer

 * @gfp	: flags to use for memory allocations

 */

static int virtscsi_add_cmd(struct virtqueue *vq,

			    struct virtio_scsi_cmd *cmd,

			    size_t req_size, size_t resp_size, gfp_t gfp)

			    size_t req_size, size_t resp_size)

{

	struct scsi_cmnd *sc = cmd->sc;

	struct scatterlist *sgs[4], req, resp;
@@ -469,19 +468,19 @@ static int virtscsi_add_cmd(struct virtqueue *vq, 
	if (in)

		sgs[out_num + in_num++] = in->sgl;



	return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, gfp);

	return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, GFP_ATOMIC);

}



static int virtscsi_kick_cmd(struct virtio_scsi_vq *vq,

			     struct virtio_scsi_cmd *cmd,

			     size_t req_size, size_t resp_size, gfp_t gfp)

			     size_t req_size, size_t resp_size)

{

	unsigned long flags;

	int err;

	bool needs_kick = false;



	spin_lock_irqsave(&vq->vq_lock, flags);

	err = virtscsi_add_cmd(vq->vq, cmd, req_size, resp_size, gfp);

	err = virtscsi_add_cmd(vq->vq, cmd, req_size, resp_size);

	if (!err)

		needs_kick = virtqueue_kick_prepare(vq->vq);
@@ -530,8 +529,7 @@ static int virtscsi_queuecommand(struct virtio_scsi *vscsi, 
	memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);



	if (virtscsi_kick_cmd(req_vq, cmd,

			      sizeof cmd->req.cmd, sizeof cmd->resp.cmd,

			      GFP_ATOMIC) == 0)

			      sizeof cmd->req.cmd, sizeof cmd->resp.cmd) == 0)

		ret = 0;

	else

		mempool_free(cmd, virtscsi_cmd_pool);
@@ -596,8 +594,7 @@ static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd) 


	cmd->comp = &comp;

	if (virtscsi_kick_cmd(&vscsi->ctrl_vq, cmd,

			      sizeof cmd->req.tmf, sizeof cmd->resp.tmf,

			      GFP_NOIO) < 0)

			      sizeof cmd->req.tmf, sizeof cmd->resp.tmf) < 0)

		goto out;



	wait_for_completion(&comp);