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Merge tag 'tag-for-linus-3.9' of git://git.linaro.org/people/sumitsemwal/linux-dma-buf

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Pull dma-buf framework updates from Sumit Semwal:
 "Refcounting implemented for vmap in core dma-buf"

* tag 'tag-for-linus-3.9' of git://git.linaro.org/people/sumitsemwal/linux-dma-buf:
  CHROMIUM: dma-buf: restore args on failure of dma_buf_mmap
  dma-buf: implement vmap refcounting in the interface logic
This commit is contained in:
Linus Torvalds
2013-02-28 19:43:13 -08:00
parent b6669737d3 495c10cc1c
commit 5e04f4b429
3 changed files with 63 additions and 13 deletions
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6
Documentation/dma-buf-sharing.txt
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@@ -302,7 +302,11 @@ Access to a dma_buf from the kernel context involves three steps:
void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
The vmap call can fail if there is no vmap support in the exporter, or if it
runs out of vmalloc space. Fallback to kmap should be implemented.
runs out of vmalloc space. Fallback to kmap should be implemented. Note that
the dma-buf layer keeps a reference count for all vmap access and calls down
into the exporter's vmap function only when no vmapping exists, and only
unmaps it once. Protection against concurrent vmap/vunmap calls is provided
by taking the dma_buf->lock mutex.
3. Finish access