dma-buf: remove kmap_atomic interface

Neither used nor correctly implemented anywhere. Just completely remove
the interface.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Sumit Semwal <sumit.semwal@linaro.org>
Link: https://patchwork.freedesktop.org/patch/226645/

1 files changed, 2 insertions, 52 deletions

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 50771063c617..13884474d158 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -405,7 +405,6 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
                           || !exp_info->ops->map_dma_buf
                           || !exp_info->ops->unmap_dma_buf
                           || !exp_info->ops->release
-                          || !exp_info->ops->map_atomic
                           || !exp_info->ops->map
                           || !exp_info->ops->mmap)) {
                 return ERR_PTR(-EINVAL);
@@ -687,26 +686,14 @@ EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);
  *      void \*dma_buf_kmap(struct dma_buf \*, unsigned long);
  *      void dma_buf_kunmap(struct dma_buf \*, unsigned long, void \*);
  *
- *   There are also atomic variants of these interfaces. Like for kmap they
- *   facilitate non-blocking fast-paths. Neither the importer nor the exporter
- *   (in the callback) is allowed to block when using these.
- *
- *   Interfaces::
- *      void \*dma_buf_kmap_atomic(struct dma_buf \*, unsigned long);
- *      void dma_buf_kunmap_atomic(struct dma_buf \*, unsigned long, void \*);
- *
- *   For importers all the restrictions of using kmap apply, like the limited
- *   supply of kmap_atomic slots. Hence an importer shall only hold onto at
- *   max 2 atomic dma_buf kmaps at the same time (in any given process context).
+ *   Implementing the functions is optional for exporters and for importers all
+ *   the restrictions of using kmap apply.
  *
  *   dma_buf kmap calls outside of the range specified in begin_cpu_access are
  *   undefined. If the range is not PAGE_SIZE aligned, kmap needs to succeed on
  *   the partial chunks at the beginning and end but may return stale or bogus
  *   data outside of the range (in these partial chunks).
  *
- *   Note that these calls need to always succeed. The exporter needs to
- *   complete any preparations that might fail in begin_cpu_access.
- *
  *   For some cases the overhead of kmap can be too high, a vmap interface
  *   is introduced. This interface should be used very carefully, as vmalloc
  *   space is a limited resources on many architectures.
@@ -860,43 +847,6 @@ int dma_buf_end_cpu_access(struct dma_buf *dmabuf,
 EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access);
 
 /**
- * dma_buf_kmap_atomic - Map a page of the buffer object into kernel address
- * space. The same restrictions as for kmap_atomic and friends apply.
- * @dmabuf:     [in]    buffer to map page from.
- * @page_num:   [in]    page in PAGE_SIZE units to map.
- *
- * This call must always succeed, any necessary preparations that might fail
- * need to be done in begin_cpu_access.
- */
-void *dma_buf_kmap_atomic(struct dma_buf *dmabuf, unsigned long page_num)
-{
-        WARN_ON(!dmabuf);
-
-        if (!dmabuf->ops->map_atomic)
-                return NULL;
-        return dmabuf->ops->map_atomic(dmabuf, page_num);
-}
-EXPORT_SYMBOL_GPL(dma_buf_kmap_atomic);
-
-/**
- * dma_buf_kunmap_atomic - Unmap a page obtained by dma_buf_kmap_atomic.
- * @dmabuf:     [in]    buffer to unmap page from.
- * @page_num:   [in]    page in PAGE_SIZE units to unmap.
- * @vaddr:      [in]    kernel space pointer obtained from dma_buf_kmap_atomic.
- *
- * This call must always succeed.
- */
-void dma_buf_kunmap_atomic(struct dma_buf *dmabuf, unsigned long page_num,
-                           void *vaddr)
-{
-        WARN_ON(!dmabuf);
-
-        if (dmabuf->ops->unmap_atomic)
-                dmabuf->ops->unmap_atomic(dmabuf, page_num, vaddr);
-}
-EXPORT_SYMBOL_GPL(dma_buf_kunmap_atomic);
-
-/**
  * dma_buf_kmap - Map a page of the buffer object into kernel address space. The
  * same restrictions as for kmap and friends apply.
  * @dmabuf:     [in]    buffer to map page from.