Re: [PATCH v2 2/8] ib_umem: Add a new, more generic ib_umem_get_attrs

[Knut Omang <knut.omang@oracle.com>]

Dough, 

This patch and the next in this set is IMHO together a generic enhancement/cleanup,
is it something you would consider to take just as that?

I am looking at suggesting a simplified, less target specific version of this set
to get it off my chest,

Thanks,
Knut

On Fri, 2016-09-16 at 20:31 +0200, Knut Omang wrote:
> This call allows a full range of DMA attributes and also
> DMA direction to be supplied and is just a refactor of the old ib_umem_get.
> Reimplement ib_umem_get using the new generic call,
> now a trivial implementation.
> ---
>  drivers/infiniband/core/umem.c | 23 +++++++++++++++--------
>  include/rdma/ib_umem.h         | 15 ++++++++++++++-
>  2 files changed, 29 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
> index c68746c..699a0f7 100644
> --- a/drivers/infiniband/core/umem.c
> +++ b/drivers/infiniband/core/umem.c
> @@ -52,7 +52,7 @@ static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int d
>  	if (umem->nmap > 0)
>  		ib_dma_unmap_sg(dev, umem->sg_head.sgl,
>  				umem->nmap,
> -				DMA_BIDIRECTIONAL);
> +				umem->dir);
>  
>  	for_each_sg(umem->sg_head.sgl, sg, umem->npages, i) {
>  
> @@ -82,6 +82,17 @@ static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int d
>  struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
>  			    size_t size, int access, int dmasync)
>  {
> +	unsigned long dma_attrs = 0;
> +	if (dmasync)
> +		dma_attrs |= DMA_ATTR_WRITE_BARRIER;
> +	return ib_umem_get_attrs(context, addr, size, access, DMA_BIDIRECTIONAL, dma_attrs);
> +}
> +EXPORT_SYMBOL(ib_umem_get);
> +
> +struct ib_umem *ib_umem_get_attrs(struct ib_ucontext *context, unsigned long addr,
> +				  size_t size, int access, enum dma_data_direction dir,
> +				  unsigned long dma_attrs)
> +{
>  	struct ib_umem *umem;
>  	struct page **page_list;
>  	struct vm_area_struct **vma_list;
> @@ -91,16 +102,11 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
>  	unsigned long npages;
>  	int ret;
>  	int i;
> -	unsigned long dma_attrs = 0;
>  	struct scatterlist *sg, *sg_list_start;
>  	int need_release = 0;
>  
> -	if (dmasync)
> -		dma_attrs |= DMA_ATTR_WRITE_BARRIER;
> -
>  	if (!size)
>  		return ERR_PTR(-EINVAL);
> -
>  	/*
>  	 * If the combination of the addr and size requested for this memory
>  	 * region causes an integer overflow, return error.
> @@ -121,6 +127,7 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
>  	umem->address   = addr;
>  	umem->page_size = PAGE_SIZE;
>  	umem->pid       = get_task_pid(current, PIDTYPE_PID);
> +	umem->dir	= dir;
>  	/*
>  	 * We ask for writable memory if any of the following
>  	 * access flags are set.  "Local write" and "remote write"
> @@ -213,7 +220,7 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
>  	umem->nmap = ib_dma_map_sg_attrs(context->device,
>  				  umem->sg_head.sgl,
>  				  umem->npages,
> -				  DMA_BIDIRECTIONAL,
> +				  dir,
>  				  dma_attrs);
>  
>  	if (umem->nmap <= 0) {
> @@ -239,7 +246,7 @@ out:
>  
>  	return ret < 0 ? ERR_PTR(ret) : umem;
>  }
> -EXPORT_SYMBOL(ib_umem_get);
> +EXPORT_SYMBOL(ib_umem_get_attrs);
>  
>  static void ib_umem_account(struct work_struct *work)
>  {
> diff --git a/include/rdma/ib_umem.h b/include/rdma/ib_umem.h
> index 2d83cfd..2876679 100644
> --- a/include/rdma/ib_umem.h
> +++ b/include/rdma/ib_umem.h
> @@ -36,6 +36,7 @@
>  #include <linux/list.h>
>  #include <linux/scatterlist.h>
>  #include <linux/workqueue.h>
> +#include <linux/dma-direction.h>
>  
>  struct ib_ucontext;
>  struct ib_umem_odp;
> @@ -47,6 +48,7 @@ struct ib_umem {
>  	int			page_size;
>  	int                     writable;
>  	int                     hugetlb;
> +	enum dma_data_direction dir;
>  	struct work_struct	work;
>  	struct pid             *pid;
>  	struct mm_struct       *mm;
> @@ -81,9 +83,12 @@ static inline size_t ib_umem_num_pages(struct ib_umem *umem)
>  }
>  
>  #ifdef CONFIG_INFINIBAND_USER_MEM
> -
>  struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
>  			    size_t size, int access, int dmasync);
> +struct ib_umem *ib_umem_get_attrs(struct ib_ucontext *context, unsigned long addr,
> +				  size_t size, int access,
> +				  enum dma_data_direction dir,
> +				  unsigned long dma_attrs);
>  void ib_umem_release(struct ib_umem *umem);
>  int ib_umem_page_count(struct ib_umem *umem);
>  int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset,
> @@ -98,6 +103,14 @@ static inline struct ib_umem *ib_umem_get(struct ib_ucontext *context,
>  					  int access, int dmasync) {
>  	return ERR_PTR(-EINVAL);
>  }
> +static inline struct ib_umem *ib_umem_get_attrs(struct ib_ucontext *context,
> +						unsigned long addr,
> +						size_t size, int access,
> +						enum dma_data_direction dir,
> +						unsigned long dma_attrs)
> +{
> +	return ERR_PTR(-EINVAL);
> +}
>  static inline void ib_umem_release(struct ib_umem *umem) { }
>  static inline int ib_umem_page_count(struct ib_umem *umem) { return 0; }
>  static inline int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset,