diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-05-25 09:37:26 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-05-25 09:37:26 -0700 |
commit | da89fb165e5e51a2ec1ff8a0ff6bc052d1068184 (patch) | |
tree | 1f15b6177a886ceef83d60c3b5a7af926442f581 /drivers/base | |
parent | d5adf235adc8d8d67c10afd43922c92753f6be3c (diff) | |
parent | b25b086d23eb852bf3cfdeb60409b4967ebb3c0c (diff) |
Merge tag 'tag-for-linus-3.5' of git://git.linaro.org/people/sumitsemwal/linux-dma-buf
Pull dma-buf updates from Sumit Semwal:
"Here's the first signed-tag pull request for dma-buf framework. It
includes the following key items:
- mmap support
- vmap support
- related documentation updates
These are needed by various drivers to allow mmap/vmap of dma-buf
shared buffers. Dave Airlie has some prime patches dependent on the
vmap pull as well."
* tag 'tag-for-linus-3.5' of git://git.linaro.org/people/sumitsemwal/linux-dma-buf:
dma-buf: add initial vmap documentation
dma-buf: minor documentation fixes.
dma-buf: add vmap interface
dma-buf: mmap support
Diffstat (limited to 'drivers/base')
-rw-r--r-- | drivers/base/dma-buf.c | 99 |
1 files changed, 98 insertions, 1 deletions
diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c index 05c64c11bad..24e88fe29ec 100644 --- a/drivers/base/dma-buf.c +++ b/drivers/base/dma-buf.c @@ -44,8 +44,26 @@ static int dma_buf_release(struct inode *inode, struct file *file) return 0; } +static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma) +{ + struct dma_buf *dmabuf; + + if (!is_dma_buf_file(file)) + return -EINVAL; + + dmabuf = file->private_data; + + /* check for overflowing the buffer's size */ + if (vma->vm_pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) > + dmabuf->size >> PAGE_SHIFT) + return -EINVAL; + + return dmabuf->ops->mmap(dmabuf, vma); +} + static const struct file_operations dma_buf_fops = { .release = dma_buf_release, + .mmap = dma_buf_mmap_internal, }; /* @@ -82,7 +100,8 @@ struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops, || !ops->unmap_dma_buf || !ops->release || !ops->kmap_atomic - || !ops->kmap)) { + || !ops->kmap + || !ops->mmap)) { return ERR_PTR(-EINVAL); } @@ -406,3 +425,81 @@ void dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long page_num, dmabuf->ops->kunmap(dmabuf, page_num, vaddr); } EXPORT_SYMBOL_GPL(dma_buf_kunmap); + + +/** + * dma_buf_mmap - Setup up a userspace mmap with the given vma + * @dmabuf: [in] buffer that should back the vma + * @vma: [in] vma for the mmap + * @pgoff: [in] offset in pages where this mmap should start within the + * dma-buf buffer. + * + * This function adjusts the passed in vma so that it points at the file of the + * dma_buf operation. It alsog adjusts the starting pgoff and does bounds + * checking on the size of the vma. Then it calls the exporters mmap function to + * set up the mapping. + * + * Can return negative error values, returns 0 on success. + */ +int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, + unsigned long pgoff) +{ + if (WARN_ON(!dmabuf || !vma)) + return -EINVAL; + + /* check for offset overflow */ + if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) < pgoff) + return -EOVERFLOW; + + /* check for overflowing the buffer's size */ + if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) > + dmabuf->size >> PAGE_SHIFT) + return -EINVAL; + + /* readjust the vma */ + if (vma->vm_file) + fput(vma->vm_file); + + vma->vm_file = dmabuf->file; + get_file(vma->vm_file); + + vma->vm_pgoff = pgoff; + + return dmabuf->ops->mmap(dmabuf, vma); +} +EXPORT_SYMBOL_GPL(dma_buf_mmap); + +/** + * dma_buf_vmap - Create virtual mapping for the buffer object into kernel + * address space. Same restrictions as for vmap and friends apply. + * @dmabuf: [in] buffer to vmap + * + * This call may fail due to lack of virtual mapping address space. + * These calls are optional in drivers. The intended use for them + * is for mapping objects linear in kernel space for high use objects. + * Please attempt to use kmap/kunmap before thinking about these interfaces. + */ +void *dma_buf_vmap(struct dma_buf *dmabuf) +{ + if (WARN_ON(!dmabuf)) + return NULL; + + if (dmabuf->ops->vmap) + return dmabuf->ops->vmap(dmabuf); + return NULL; +} +EXPORT_SYMBOL_GPL(dma_buf_vmap); + +/** + * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap. + * @dmabuf: [in] buffer to vunmap + */ +void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr) +{ + if (WARN_ON(!dmabuf)) + return; + + if (dmabuf->ops->vunmap) + dmabuf->ops->vunmap(dmabuf, vaddr); +} +EXPORT_SYMBOL_GPL(dma_buf_vunmap); |