[PATCH] nvme/pci: Rerun irq setup on IO queue init errors

[ming.lei@redhat.com (Ming Lei)]

On Fri, Jan 04, 2019@03:04:33PM -0700, Keith Busch wrote:
> If the driver is unable to create a subset of IO queues for any reason,
> the read/write and polled queue sets will not match the actual allocated
> hardware contexts. This leaves gaps in the CPU affinity mappings and
> causes the following kernel panic after blk_mq_map_queue_type() returns
> a NULL hctx.
> 
>   BUG: unable to handle kernel NULL pointer dereference at 0000000000000198
>   #PF error: [normal kernel read fault]
>   PGD 0 P4D 0
>   Oops: 0000 [#1] SMP
>   CPU: 64 PID: 1171 Comm: kworker/u259:1 Not tainted 4.20.0+ #241
>   Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-2.fc27 04/01/2014
>   Workqueue: nvme-wq nvme_scan_work [nvme_core]
>   RIP: 0010:blk_mq_init_allocated_queue+0x2d9/0x440
>   RSP: 0018:ffffb1bf0abc3cd0 EFLAGS: 00010286
>   RAX: 000000000000001f RBX: ffff8ea744cf0718 RCX: 0000000000000000
>   RDX: 0000000000000002 RSI: 000000000000007c RDI: ffffffff9109a820
>   RBP: ffff8ea7565f7008 R08: 000000000000001f R09: 000000000000003f
>   R10: ffffb1bf0abc3c00 R11: 0000000000000000 R12: 000000000001d008
>   R13: ffff8ea7565f7008 R14: 000000000000003f R15: 0000000000000001
>   FS:  0000000000000000(0000) GS:ffff8ea757200000(0000) knlGS:0000000000000000
>   CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>   CR2: 0000000000000198 CR3: 0000000013058000 CR4: 00000000000006e0
>   DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>   DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>   Call Trace:
>    blk_mq_init_queue+0x35/0x60
>    nvme_validate_ns+0xc6/0x7c0 [nvme_core]
>    ? nvme_identify_ctrl.isra.56+0x7e/0xc0 [nvme_core]
>    nvme_scan_work+0xc8/0x340 [nvme_core]
>    ? __wake_up_common+0x6d/0x120
>    ? try_to_wake_up+0x55/0x410
>    process_one_work+0x1e9/0x3d0
>    worker_thread+0x2d/0x3d0
>    ? process_one_work+0x3d0/0x3d0
>    kthread+0x111/0x130
>    ? kthread_park+0x90/0x90
>    ret_from_fork+0x1f/0x30
>   Modules linked in: nvme nvme_core serio_raw
>   CR2: 0000000000000198
> 
> Fix by re-running the interrupt vector setup from scratch using a reduced
> count that may be successful until the created queues matches the irq
> affinity plus polling queue sets.
> 
> Signed-off-by: Keith Busch <keith.busch at intel.com>
> ---
> Discussed in previous patch here:
> 
>   http://lists.infradead.org/pipermail/linux-nvme/2019-January/021956.html
> 
> 
>  drivers/nvme/host/pci.c | 50 +++++++++++++++++++++++++++++++++++--------------
>  1 file changed, 36 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index 98332d0a80f0..49cdb3a23487 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -95,6 +95,7 @@ struct nvme_dev;
>  struct nvme_queue;
>  
>  static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown);
> +static bool __nvme_disable_io_queues(struct nvme_dev *dev, u8 opcode);
>  
>  /*
>   * Represents an NVM Express device.  Each nvme_dev is a PCI function.
> @@ -1420,6 +1421,14 @@ static int nvme_suspend_queue(struct nvme_queue *nvmeq)
>  	return 0;
>  }
>  
> +static void nvme_suspend_io_queues(struct nvme_dev *dev)
> +{
> +	int i;
> +
> +	for (i = dev->ctrl.queue_count - 1; i > 0; i--)
> +		nvme_suspend_queue(&dev->queues[i]);
> +}
> +
>  static void nvme_disable_admin_queue(struct nvme_dev *dev, bool shutdown)
>  {
>  	struct nvme_queue *nvmeq = &dev->queues[0];
> @@ -2132,6 +2141,12 @@ static int nvme_setup_irqs(struct nvme_dev *dev, unsigned int nr_io_queues)
>  	return result;
>  }
>  
> +static void nvme_disable_io_queues(struct nvme_dev *dev)
> +{
> +	if (__nvme_disable_io_queues(dev, nvme_admin_delete_sq))
> +		__nvme_disable_io_queues(dev, nvme_admin_delete_cq);
> +}
> +
>  static int nvme_setup_io_queues(struct nvme_dev *dev)
>  {
>  	struct nvme_queue *adminq = &dev->queues[0];
> @@ -2168,6 +2183,7 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
>  	} while (1);
>  	adminq->q_db = dev->dbs;
>  
> + retry:
>  	/* Deregister the admin queue's interrupt */
>  	pci_free_irq(pdev, 0, adminq);
>  
> @@ -2185,25 +2201,34 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
>  	result = max(result - 1, 1);
>  	dev->max_qid = result + dev->io_queues[HCTX_TYPE_POLL];
>  
> -	dev_info(dev->ctrl.device, "%d/%d/%d default/read/poll queues\n",
> -					dev->io_queues[HCTX_TYPE_DEFAULT],
> -					dev->io_queues[HCTX_TYPE_READ],
> -					dev->io_queues[HCTX_TYPE_POLL]);
> -
>  	/*
>  	 * Should investigate if there's a performance win from allocating
>  	 * more queues than interrupt vectors; it might allow the submission
>  	 * path to scale better, even if the receive path is limited by the
>  	 * number of interrupts.
>  	 */
> -
>  	result = queue_request_irq(adminq);
>  	if (result) {
>  		adminq->cq_vector = -1;
>  		return result;
>  	}
>  	set_bit(NVMEQ_ENABLED, &adminq->flags);
> -	return nvme_create_io_queues(dev);
> +
> +	result = nvme_create_io_queues(dev);
> +	if (result || dev->online_queues < 2)
> +		return result;
> +
> +	if (dev->online_queues - 1 < dev->max_qid) {
> +		nr_io_queues = dev->online_queues - 1;
> +		nvme_disable_io_queues(dev);
> +		nvme_suspend_io_queues(dev);
> +		goto retry;
> +	}
> +	dev_info(dev->ctrl.device, "%d/%d/%d default/read/poll queues\n",
> +					dev->io_queues[HCTX_TYPE_DEFAULT],
> +					dev->io_queues[HCTX_TYPE_READ],
> +					dev->io_queues[HCTX_TYPE_POLL]);
> +	return 0;
>  }
>  
>  static void nvme_del_queue_end(struct request *req, blk_status_t error)
> @@ -2248,7 +2273,7 @@ static int nvme_delete_queue(struct nvme_queue *nvmeq, u8 opcode)
>  	return 0;
>  }
>  
> -static bool nvme_disable_io_queues(struct nvme_dev *dev, u8 opcode)
> +static bool __nvme_disable_io_queues(struct nvme_dev *dev, u8 opcode)
>  {
>  	int nr_queues = dev->online_queues - 1, sent = 0;
>  	unsigned long timeout;
> @@ -2407,7 +2432,6 @@ static void nvme_pci_disable(struct nvme_dev *dev)
>  
>  static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown)
>  {
> -	int i;
>  	bool dead = true;
>  	struct pci_dev *pdev = to_pci_dev(dev->dev);
>  
> @@ -2434,13 +2458,11 @@ static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown)
>  	nvme_stop_queues(&dev->ctrl);
>  
>  	if (!dead && dev->ctrl.queue_count > 0) {
> -		if (nvme_disable_io_queues(dev, nvme_admin_delete_sq))
> -			nvme_disable_io_queues(dev, nvme_admin_delete_cq);
> +		nvme_disable_io_queues(dev);
>  		nvme_disable_admin_queue(dev, shutdown);
>  	}
> -	for (i = dev->ctrl.queue_count - 1; i >= 0; i--)
> -		nvme_suspend_queue(&dev->queues[i]);
> -
> +	nvme_suspend_io_queues(dev);
> +	nvme_suspend_queue(&dev->queues[0]);
>  	nvme_pci_disable(dev);
>  
>  	blk_mq_tagset_busy_iter(&dev->tagset, nvme_cancel_request, &dev->ctrl);
> -- 

This patch may cover failure during creating queues, so:

	Reviewed-by: Ming Lei <ming.lei at redhat.com>

But it can't cover RH's report on aarch64 boot failure, and the
following patch is still needed:

http://lists.infradead.org/pipermail/linux-nvme/2019-January/021902.html

Thanks,
Ming