Re: [PATCH v2 03/17] misc/habana: Stop using frame_vector helpers

Oded Gabbay
2020-10-10T23:09:15Z

On Fri, Oct 9, 2020 at 10:59 AM Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
>
> All we need are a pages array, pin_user_pages_fast can give us that
> directly. Plus this avoids the entire raw pfn side of get_vaddr_frames.
>
Thanks for the patch Daniel.

> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> Cc: Jason Gunthorpe <jgg@ziepe.ca>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: John Hubbard <jhubbard@nvidia.com>
> Cc: Jérôme Glisse <jglisse@redhat.com>
> Cc: Jan Kara <jack@suse.cz>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: linux-mm@kvack.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-samsung-soc@vger.kernel.org
> Cc: linux-media@vger.kernel.org
> Cc: Oded Gabbay <oded.gabbay@gmail.com>
> Cc: Omer Shpigelman <oshpigelman@habana.ai>
> Cc: Ofir Bitton <obitton@habana.ai>
> Cc: Tomer Tayar <ttayar@habana.ai>
> Cc: Moti Haimovski <mhaimovski@habana.ai>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Pawel Piskorski <ppiskorski@habana.ai>
> --
> v2: Use unpin_user_pages_dirty_lock (John)
> ---
> drivers/misc/habanalabs/Kconfig | 1 -
> drivers/misc/habanalabs/common/habanalabs.h | 3 +-
> drivers/misc/habanalabs/common/memory.c | 49 ++++++++-------------
> 3 files changed, 20 insertions(+), 33 deletions(-)
>
> diff --git a/drivers/misc/habanalabs/Kconfig b/drivers/misc/habanalabs/Kconfig
> index 8eb5d38c618e..2f04187f7167 100644
> --- a/drivers/misc/habanalabs/Kconfig
> +++ b/drivers/misc/habanalabs/Kconfig
> @@ -6,7 +6,6 @@
> config HABANA_AI
> tristate "HabanaAI accelerators (habanalabs)"
> depends on PCI && HAS_IOMEM
> - select FRAME_VECTOR
> select DMA_SHARED_BUFFER
> select GENERIC_ALLOCATOR
> select HWMON
> diff --git a/drivers/misc/habanalabs/common/habanalabs.h b/drivers/misc/habanalabs/common/habanalabs.h
> index edbd627b29d2..c1b3ad613b15 100644
> --- a/drivers/misc/habanalabs/common/habanalabs.h
> +++ b/drivers/misc/habanalabs/common/habanalabs.h
> @@ -881,7 +881,8 @@ struct hl_ctx_mgr {
> struct hl_userptr {
> enum vm_type_t vm_type; /* must be first */
> struct list_head job_node;
> - struct frame_vector *vec;
> + struct page **pages;
> + unsigned int npages;
Can you please update the kerneldoc comment section of this structure
according to your changes ?

> struct sg_table *sgt;
> enum dma_data_direction dir;
> struct list_head debugfs_list;
> diff --git a/drivers/misc/habanalabs/common/memory.c b/drivers/misc/habanalabs/common/memory.c
> index 5ff4688683fd..327b64479f97 100644
> --- a/drivers/misc/habanalabs/common/memory.c
> +++ b/drivers/misc/habanalabs/common/memory.c
> @@ -1281,45 +1281,41 @@ static int get_user_memory(struct hl_device *hdev, u64 addr, u64 size,
> return -EFAULT;
> }
>
> - userptr->vec = frame_vector_create(npages);
> - if (!userptr->vec) {
> + userptr->pages = kvmalloc_array(npages, sizeof(*userptr->pages),
> + GFP_KERNEL);
> + if (!userptr->pages) {
> dev_err(hdev->dev, "Failed to create frame vector\n");
> return -ENOMEM;
> }
>
> - rc = get_vaddr_frames(start, npages, FOLL_FORCE | FOLL_WRITE,
> - userptr->vec);
> + rc = pin_user_pages_fast(start, npages, FOLL_FORCE | FOLL_WRITE,
> + userptr->pages);
>
> if (rc != npages) {
> dev_err(hdev->dev,
> "Failed to map host memory, user ptr probably wrong\n");
> if (rc < 0)
> - goto destroy_framevec;
> + goto destroy_pages;
> + npages = rc;
> rc = -EFAULT;
> - goto put_framevec;
> - }
> -
> - if (frame_vector_to_pages(userptr->vec) < 0) {
> - dev_err(hdev->dev,
> - "Failed to translate frame vector to pages\n");
> - rc = -EFAULT;
> - goto put_framevec;
> + goto put_pages;
> }
> + userptr->npages = npages;
>
> rc = sg_alloc_table_from_pages(userptr->sgt,
> - frame_vector_pages(userptr->vec),
> - npages, offset, size, GFP_ATOMIC);
> + userptr->pages,
> + npages, offset, size, GFP_ATOMIC);
I think that because the call to kvmalloc_array() is done with
GFP_KERNEL, there is no point in using GFP_ATOMIC here.
And actually, this path only needs to avoid yielding when using a
special debug mode.
So I suggest putting here GFP_KERNEL.

In the meanwhile, I'll run this patch (coupled with the next patch) in
our C/I to make sure there are no regressions.
Thanks,
Oded

> if (rc < 0) {
> dev_err(hdev->dev, "failed to create SG table from pages\n");
> - goto put_framevec;
> + goto put_pages;
> }
>
> return 0;
>
> -put_framevec:
> - put_vaddr_frames(userptr->vec);
> -destroy_framevec:
> - frame_vector_destroy(userptr->vec);
> +put_pages:
> + unpin_user_pages(userptr->pages, npages);
> +destroy_pages:
> + kvfree(userptr->pages);
> return rc;
> }
>
> @@ -1405,8 +1401,6 @@ int hl_pin_host_memory(struct hl_device *hdev, u64 addr, u64 size,
> */
> void hl_unpin_host_memory(struct hl_device *hdev, struct hl_userptr *userptr)
> {
> - struct page **pages;
> -
> hl_debugfs_remove_userptr(hdev, userptr);
>
> if (userptr->dma_mapped)
> @@ -1414,15 +1408,8 @@ void hl_unpin_host_memory(struct hl_device *hdev, struct hl_userptr *userptr)
> userptr->sgt->nents,
> userptr->dir);
>
> - pages = frame_vector_pages(userptr->vec);
> - if (!IS_ERR(pages)) {
> - int i;
> -
> - for (i = 0; i < frame_vector_count(userptr->vec); i++)
> - set_page_dirty_lock(pages[i]);
> - }
> - put_vaddr_frames(userptr->vec);
> - frame_vector_destroy(userptr->vec);
> + unpin_user_pages_dirty_lock(userptr->pages, userptr->npages, true);
> + kvfree(userptr->pages);
>
> list_del(&userptr->job_node);
>
> --
> 2.28.0
>