Am 28.06.2018 um 11:53 schrieb Zhang, Jerry (Junwei):
On 06/22/2018 10:11 PM, Christian König wrote:
Add function variants which can be called with the reservation lock already held.
v2: reordered, add lockdep asserts, fix kerneldoc
Signed-off-by: Christian König christian.koenig@amd.com
drivers/dma-buf/dma-buf.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++ include/linux/dma-buf.h | 5 +++++ 2 files changed, 62 insertions(+)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 852a3928ee71..dc94e76e2e2a 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -606,6 +606,40 @@ 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;
Perhaps better to add some error check, like dma_buf_map_attachment()
WARN_ON(!attach || !attach->dmabuf)
Actually I wanted to remove those from the other functions as well.
WARN_ON and BUG_ON checks for NULL pointers before using them are totally pointless because they have the same effect as a crash.
Regards, Christian.
Apart from that, it's Reviewed-by: Junwei Zhang Jerry.Zhang@amd.com
Jerry
+ might_sleep(); + reservation_object_assert_held(attach->dmabuf->resv);
+ 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 @@ -639,6 +673,29 @@ 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);
+ 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 diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 991787a03199..a25e754ae2f7 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -384,8 +384,13 @@ 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,