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 v4: reorder once more
Signed-off-by: Christian König christian.koenig@amd.com --- drivers/dma-buf/dma-buf.c | 83 +++++++++++++++++++++++++++++++++------ include/linux/dma-buf.h | 5 +++ 2 files changed, 76 insertions(+), 12 deletions(-)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 0aa97bb05636..95bcd2ed795b 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -660,6 +660,48 @@ 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(). 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; + int r; + + might_sleep(); + reservation_object_assert_held(attach->dmabuf->resv); + + if (attach->sgt) + return attach->sgt; + + r = dma_buf_pin(attach->dmabuf); + if (r) + return ERR_PTR(r); + + sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction); + if (!sg_table) + return 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 @@ -679,7 +721,6 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach, enum dma_data_direction direction) { struct sg_table *sg_table; - int r;
might_sleep();
@@ -690,21 +731,40 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach, return attach->sgt;
reservation_object_lock(attach->dmabuf->resv, NULL); - r = dma_buf_pin(attach->dmabuf); - if (r) { - reservation_object_unlock(attach->dmabuf->resv); - return ERR_PTR(r); - } - - sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction); - if (!sg_table) - sg_table = ERR_PTR(-ENOMEM); + sg_table = dma_buf_map_attachment(attach, direction); reservation_object_unlock(attach->dmabuf->resv);
return sg_table; } 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); + dma_buf_unpin(attach->dmabuf); +} +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 @@ -728,8 +788,7 @@ void dma_buf_unmap_attachment(struct dma_buf_attachment *attach, return;
reservation_object_lock(attach->dmabuf->resv, NULL); - attach->dmabuf->ops->unmap_dma_buf(attach, sg_table, direction); - dma_buf_unpin(attach->dmabuf); + dma_buf_unmap_attachment_locked(attach, sg_table, direction); reservation_object_unlock(attach->dmabuf->resv); } EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment); diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 425a771d229c..f7d6fc049b39 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -427,8 +427,13 @@ 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,