On 9/20/2018 6:21 AM, Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro@xxxxxxxxxxxx>
>
> Prepare IB device name field to rename operation by ensuring that all
> accesses to it are protected with lock and users don't see part of name.
>
> The protection is done with global device_lock because it is used in
> allocation and deallocation phases. At this stage, this lock is not
> busy and easily can be moved to be per-device, once it will be needed.
>
> Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>
> ---
> drivers/infiniband/core/device.c | 24 +++++++++++++++++++++++-
> include/rdma/ib_verbs.h | 8 +++++++-
> 2 files changed, 30 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
> index 5a680a88aa87..3270cde6d806 100644
> --- a/drivers/infiniband/core/device.c
> +++ b/drivers/infiniband/core/device.c
> @@ -170,6 +170,14 @@ static struct ib_device *__ib_device_get_by_name(const char *name)
> return NULL;
> }
>
> +void ib_device_get_name(struct ib_device *ibdev, char *name)
> +{
> + down_read(&lists_rwsem);
> + strlcpy(name, ibdev->name, IB_DEVICE_NAME_MAX);
> + up_read(&lists_rwsem);
> +}
> +EXPORT_SYMBOL(ib_device_get_name);
> +
> static int alloc_name(char *name)
> {
> unsigned long *inuse;
> @@ -202,6 +210,21 @@ static int alloc_name(char *name)
> return 0;
> }
>
> +int ib_device_alloc_name(struct ib_device *ibdev, const char *pattern)
> +{
> + int ret = 0;
> +
> + mutex_lock(&device_mutex);
> + strlcpy(ibdev->name, pattern, IB_DEVICE_NAME_MAX);
> + if (strchr(ibdev->name, '%'))
> + ret = alloc_name(ibdev->name);
> +
> + mutex_unlock(&device_mutex);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL(ib_device_alloc_name);
> +
> static void ib_device_release(struct device *device)
> {
> struct ib_device *dev = container_of(device, struct ib_device, dev);
> @@ -499,7 +522,6 @@ int ib_register_device(struct ib_device *device,
> ret = alloc_name(device->name);
> if (ret)
> goto out;
> - }
I don't think this is correct...
>
> if (ib_device_check_mandatory(device)) {
> ret = -EINVAL;
> diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
> index e764ed1f6025..66660e7b9854 100644
> --- a/include/rdma/ib_verbs.h
> +++ b/include/rdma/ib_verbs.h
> @@ -2260,6 +2260,11 @@ struct ib_device {
> /* Do not access @dma_device directly from ULP nor from HW drivers. */
> struct device *dma_device;
>
> + /*
> + * Do not access @name directly,
> + * use ib_device_get_name()/ib_device_alloc_name()
> + * and don't assume that it can't change after access.
> + */
> char name[IB_DEVICE_NAME_MAX];
>
> struct list_head event_handler_list;
> @@ -2638,7 +2643,8 @@ struct ib_device *ib_alloc_device(size_t size);
> void ib_dealloc_device(struct ib_device *device);
>
> void ib_get_device_fw_str(struct ib_device *device, char *str);
> -
> +int ib_device_alloc_name(struct ib_device *ibdev, const char *pattern);
> +void ib_device_get_name(struct ib_device *ibdev, char *name);
> int ib_register_device(struct ib_device *device,
> int (*port_callback)(struct ib_device *,
> u8, struct kobject *));
> --
> 2.14.4
>
