Hi Jeff
Can you detail more in the commit log that we can understand the
synchronization problematic scenario. And how does this commit fix it?
> -----Original Message-----
> From: Jeff Guo <jia....@intel.com>
> Sent: Tuesday, November 6, 2018 8:07 AM
> To: konstantin.anan...@intel.com; anatoly.bura...@intel.com; Thomas
> Monjalon <tho...@monjalon.net>; bernard.iremon...@intel.com;
> jingjing...@intel.com; wenzhuo...@intel.com
> Cc: ferruh.yi...@intel.com; dev@dpdk.org; jia....@intel.com;
> helin.zh...@intel.com; Matan Azrad <ma...@mellanox.com>;
> shaopeng...@intel.com
> Subject: [PATCH 2/3] vfio: fix to add handler lock for hot-unplug
>
> This patch add hot-unplug handler lock and unlock in device request handler
> when process bus and device resource, in order to avoid the synchronization
> issue when device be hot-unplugged.
>
> Fixes: c115fd000c32 ("vfio: handle hotplug request notifier")
> Signed-off-by: Jeff Guo <jia....@intel.com>
> ---
> drivers/bus/pci/linux/pci_vfio.c | 14 +++++++++++++-
> 1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/bus/pci/linux/pci_vfio.c
> b/drivers/bus/pci/linux/pci_vfio.c
> index 305cc06..d2c8410 100644
> --- a/drivers/bus/pci/linux/pci_vfio.c
> +++ b/drivers/bus/pci/linux/pci_vfio.c
> @@ -19,6 +19,7 @@
> #include <rte_vfio.h>
> #include <rte_eal.h>
> #include <rte_bus.h>
> +#include <rte_spinlock.h>
>
> #include "eal_filesystem.h"
>
> @@ -35,6 +36,14 @@
> * This file is only compiled if CONFIG_RTE_EAL_VFIO is set to "y".
> */
>
> +/*
> + * spinlock for device hot-unplug failure handling. If it try to access
> +bus or
> + * device, such as handle sigbus on bus or handle memory failure for
> +device
> + * just need to use this lock. It could protect the bus and the device
> +to avoid
> + * race condition.
> + */
> +static rte_spinlock_t failure_handle_lock = RTE_SPINLOCK_INITIALIZER;
> +
> #ifdef VFIO_PRESENT
>
> #ifndef PAGE_SIZE
> @@ -289,11 +298,12 @@ pci_vfio_req_handler(void *param)
> int ret;
> struct rte_device *device = (struct rte_device *)param;
>
> + rte_spinlock_lock(&failure_handle_lock);
> bus = rte_bus_find_by_device(device);
> if (bus == NULL) {
> RTE_LOG(ERR, EAL, "Cannot find bus for device (%s)\n",
> device->name);
> - return;
> + goto handle_end;
> }
>
> /*
> @@ -306,6 +316,8 @@ pci_vfio_req_handler(void *param)
> RTE_LOG(ERR, EAL,
> "Can not handle hot-unplug for device (%s)\n",
> device->name);
> +handle_end:
> + rte_spinlock_unlock(&failure_handle_lock);
> }
>
> /* enable notifier (only enable req now) */
> --
> 2.7.4
