diff options
author | Christian König <christian.koenig@amd.com> | 2018-05-30 15:15:07 +0200 |
---|---|---|
committer | Christian König <christian.koenig@amd.com> | 2018-07-11 09:35:01 +0200 |
commit | 3d9a8592753689224be4f5ee51a5d21012b2a16b (patch) | |
tree | 0f6dd7fca1365fa725767a2295a3ce4319d78bf3 | |
parent | d4634feedab2ba886a69147284ae467ff75b5b70 (diff) |
dma-buf: add dma_buf_(un)map_attachment_locked variants v3
Add function variants which can be called with the reservation lock
already held.
v2: reordered, add lockdep asserts, fix kerneldoc
v3: rebased on sgt caching
Signed-off-by: Christian König <christian.koenig@amd.com>
-rw-r--r-- | drivers/dma-buf/dma-buf.c | 63 | ||||
-rw-r--r-- | include/linux/dma-buf.h | 5 |
2 files changed, 68 insertions, 0 deletions
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 0bea5eecf554..e68322c953a9 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -625,6 +625,43 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) EXPORT_SYMBOL_GPL(dma_buf_detach); /** + * dma_buf_map_attachment_locked - Maps the buffer into _device_ address space + * with the reservation lock held. Is a wrapper for map_dma_buf() of the + * + * Returns the scatterlist table of the attachment; + * dma_buf_ops. + * @attach: [in] attachment whose scatterlist is to be returned + * @direction: [in] direction of DMA transfer + * + * Returns sg_table containing the scatterlist to be returned; returns ERR_PTR + * on error. May return -EINTR if it is interrupted by a signal. + * + * A mapping must be unmapped by using dma_buf_unmap_attachment_locked(). Note + * that the underlying backing storage is pinned for as long as a mapping + * exists, therefore users/importers should not hold onto a mapping for undue + * amounts of time. + */ +struct sg_table * +dma_buf_map_attachment_locked(struct dma_buf_attachment *attach, + enum dma_data_direction direction) +{ + struct sg_table *sg_table; + + might_sleep(); + reservation_object_assert_held(attach->dmabuf->resv); + + if (attach->sgt) + return attach->sgt; + + sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction); + if (!sg_table) + sg_table = ERR_PTR(-ENOMEM); + + return sg_table; +} +EXPORT_SYMBOL_GPL(dma_buf_map_attachment_locked); + +/** * dma_buf_map_attachment - Returns the scatterlist table of the attachment; * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the * dma_buf_ops. @@ -661,6 +698,32 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach, EXPORT_SYMBOL_GPL(dma_buf_map_attachment); /** + * dma_buf_unmap_attachment_locked - unmaps the buffer with reservation lock + * held, should deallocate the associated scatterlist. Is a wrapper for + * unmap_dma_buf() of dma_buf_ops. + * @attach: [in] attachment to unmap buffer from + * @sg_table: [in] scatterlist info of the buffer to unmap + * @direction: [in] direction of DMA transfer + * + * This unmaps a DMA mapping for @attached obtained by + * dma_buf_map_attachment_locked(). + */ +void dma_buf_unmap_attachment_locked(struct dma_buf_attachment *attach, + struct sg_table *sg_table, + enum dma_data_direction direction) +{ + might_sleep(); + reservation_object_assert_held(attach->dmabuf->resv); + + if (attach->sgt == sg_table) + return; + + attach->dmabuf->ops->unmap_dma_buf(attach, sg_table, + direction); +} +EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment_locked); + +/** * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of * dma_buf_ops. diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 6534a6769e17..a40f8f586a95 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -395,8 +395,13 @@ int dma_buf_fd(struct dma_buf *dmabuf, int flags); struct dma_buf *dma_buf_get(int fd); void dma_buf_put(struct dma_buf *dmabuf); +struct sg_table *dma_buf_map_attachment_locked(struct dma_buf_attachment *, + enum dma_data_direction); struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *, enum dma_data_direction); +void dma_buf_unmap_attachment_locked(struct dma_buf_attachment *, + struct sg_table *, + enum dma_data_direction); void dma_buf_unmap_attachment(struct dma_buf_attachment *, struct sg_table *, enum dma_data_direction); int dma_buf_begin_cpu_access(struct dma_buf *dma_buf, |