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authorChristian König <christian.koenig@amd.com>2018-05-28 13:34:01 +0200
committerChristian König <easy2remember.chk@googlemail.com>2018-06-20 15:59:34 +0200
commitf664a52695429b68afb4e130a0f69cd5fd1fec86 (patch)
tree3d16603cc6349636f191c027a517a7539adc8545 /drivers/dma-buf
parenta19741e5e5a9f1f02f8e3c037bde7d73d4bfae9c (diff)
downloadlinux-f664a52695429b68afb4e130a0f69cd5fd1fec86.tar.bz2
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/
Diffstat (limited to 'drivers/dma-buf')
-rw-r--r--drivers/dma-buf/dma-buf.c54
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.