Re: [PATCH v5 rdma-next 1/6] RDMA/core: Create mmap database and cookie helper functions

[Leon Romanovsky <leon@kernel.org>]

On Mon, Jul 08, 2019 at 12:14:58PM +0300, Michal Kalderon wrote:
> Create some common API's for adding entries to a xa_mmap.
> Searching for an entry and freeing one.
>
> The code was copied from the efa driver almost as is, just renamed
> function to be generic and not efa specific.
>
> Signed-off-by: Michal Kalderon <michal.kalderon@marvell.com>
> ---
>  drivers/infiniband/core/device.c      |   1 +
>  drivers/infiniband/core/rdma_core.c   |   1 +
>  drivers/infiniband/core/uverbs_cmd.c  |   1 +
>  drivers/infiniband/core/uverbs_main.c | 105 ++++++++++++++++++++++++++++++++++
>  include/rdma/ib_verbs.h               |  32 +++++++++++
>  5 files changed, 140 insertions(+)
>
> diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
> index 8a6ccb936dfe..a830c2c5d691 100644
> --- a/drivers/infiniband/core/device.c
> +++ b/drivers/infiniband/core/device.c
> @@ -2521,6 +2521,7 @@ void ib_set_device_ops(struct ib_device *dev, const struct ib_device_ops *ops)
>  	SET_DEVICE_OP(dev_ops, map_mr_sg_pi);
>  	SET_DEVICE_OP(dev_ops, map_phys_fmr);
>  	SET_DEVICE_OP(dev_ops, mmap);
> +	SET_DEVICE_OP(dev_ops, mmap_free);
>  	SET_DEVICE_OP(dev_ops, modify_ah);
>  	SET_DEVICE_OP(dev_ops, modify_cq);
>  	SET_DEVICE_OP(dev_ops, modify_device);
> diff --git a/drivers/infiniband/core/rdma_core.c b/drivers/infiniband/core/rdma_core.c
> index ccf4d069c25c..7166741834c8 100644
> --- a/drivers/infiniband/core/rdma_core.c
> +++ b/drivers/infiniband/core/rdma_core.c
> @@ -817,6 +817,7 @@ static void ufile_destroy_ucontext(struct ib_uverbs_file *ufile,
>  	rdma_restrack_del(&ucontext->res);
>
>  	ib_dev->ops.dealloc_ucontext(ucontext);
> +	rdma_user_mmap_entries_remove_free(ucontext);
>  	kfree(ucontext);
>
>  	ufile->ucontext = NULL;
> diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
> index 7ddd0e5bc6b3..44c0600245e4 100644
> --- a/drivers/infiniband/core/uverbs_cmd.c
> +++ b/drivers/infiniband/core/uverbs_cmd.c
> @@ -254,6 +254,7 @@ static int ib_uverbs_get_context(struct uverbs_attr_bundle *attrs)
>
>  	mutex_init(&ucontext->per_mm_list_lock);
>  	INIT_LIST_HEAD(&ucontext->per_mm_list);
> +	xa_init(&ucontext->mmap_xa);
>
>  	ret = get_unused_fd_flags(O_CLOEXEC);
>  	if (ret < 0)
> diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c
> index 11c13c1381cf..37507cc27e8c 100644
> --- a/drivers/infiniband/core/uverbs_main.c
> +++ b/drivers/infiniband/core/uverbs_main.c
> @@ -965,6 +965,111 @@ int rdma_user_mmap_io(struct ib_ucontext *ucontext, struct vm_area_struct *vma,
>  }
>  EXPORT_SYMBOL(rdma_user_mmap_io);
>
> +static inline u64
> +rdma_user_mmap_get_key(const struct rdma_user_mmap_entry *entry)
> +{
> +	return (u64)entry->mmap_page << PAGE_SHIFT;
> +}
> +
> +struct rdma_user_mmap_entry *
> +rdma_user_mmap_entry_get(struct ib_ucontext *ucontext, u64 key, u64 len)
> +{
> +	struct rdma_user_mmap_entry *entry;
> +	u64 mmap_page;
> +
> +	mmap_page = key >> PAGE_SHIFT;
> +	if (mmap_page > U32_MAX)
> +		return NULL;
> +
> +	entry = xa_load(&ucontext->mmap_xa, mmap_page);
> +	if (!entry || rdma_user_mmap_get_key(entry) != key ||
> +	    entry->length != len)
> +		return NULL;
> +
> +	ibdev_dbg(ucontext->device,
> +		  "mmap: obj[0x%p] key[%#llx] addr[%#llx] len[%#llx] removed\n",
> +		  entry->obj, key, entry->address, entry->length);
> +
> +	return entry;
> +}
> +EXPORT_SYMBOL(rdma_user_mmap_entry_get);

Please add function description in kernel doc format for all newly EXPORT_SYMBOL()
functions you introduced in RDMA/core.

> +
> +/*
> + * Note this locking scheme cannot support removal of entries, except during
> + * ucontext destruction when the core code guarentees no concurrency.
> + */
> +u64 rdma_user_mmap_entry_insert(struct ib_ucontext *ucontext, void *obj,
> +				u64 address, u64 length, u8 mmap_flag)
> +{
> +	struct rdma_user_mmap_entry *entry;
> +	u32 next_mmap_page;
> +	int err;
> +
> +	entry = kmalloc(sizeof(*entry), GFP_KERNEL);

It is worth to use kzalloc and not kmalloc.

Thanks