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authorDaniel Vetter <daniel.vetter@ffwll.ch>2021-01-07 10:46:32 +0100
committerDaniel Vetter <daniel.vetter@ffwll.ch>2021-01-07 10:46:32 +0100
commit18589d74f45d6af7e7614b6488543d723ebf236a (patch)
treea735d6ed4ea46926766d981c3944651fb78e2dc6 /drivers/dma-buf
parente71ba9452f0b5b2e8dc8aa5445198cd9214a6a62 (diff)
parentc545781e1c55ab680dcc49c37212d5327b9d6812 (diff)
Merge tag 'drm-misc-next-2020-12-17' of git://anongit.freedesktop.org/drm/drm-misc into drm-next
drm-misc-next for v5.12: UAPI Changes: - Not necessarily one, but we document that userspace needs to force probe connectors. Cross-subsystem Changes: - Require FB_ATY_CT for aty on sparc64. - video: Fix documentation, and a few compiler warnings. - Add devicetree bindings for DP connectors. - dma-buf: Update kernel-doc, and add might_lock for resv objects in begin/end_cpu_access. Core Changes: - ttm: Warn when releasing a pinned bo. - ttm: Cleanup bo size handling. - cma-helper: Remove prime infix, and implement mmap as GEM CMA functions. - Split drm_prime_sg_to_page_addr_arrays into 2 functions. - Add a new api to install irq using devm. - Update panel kerneldoc to inline style. - Add DP support to drm/bridge. - Assorted small fixes to ttm, fb-helper, scheduler. - Add atomic_commit_setup function callback. - Automatically use the atomic gamma_set, instead of forcing drivers to declare the default atomic version. - Allow using degamma for legacy gamma if gamma is not available. - Clarify that primary/cursor planes are not tied to 1 crtc (depending on possible_crtcs). - ttm: Cleanup the lru handler. Driver Changes: - Add pm support to ingenic. - Assorted small fixes in radeon, via, rockchip, omap2fb, kmb, gma500, nouveau, virtio, hisilicon, ingenic, s6e63m0 panel, ast, udlfb. - Add BOE NV110WTM-N61, ys57pss36bh5gq, Khadas TS050 panels. - Stop using pages with drm_prime_sg_to_page_addr_arrays, and switch all callers to use ttm_sg_tt_init. - Cleanup compiler and docbook warnings in a lot of fbdev devices. - Use the drmm_vram_helper in hisilicon. - Add support for BCM2711 DSI1 in vc4. - Add support for 8-bit delta RGB panels to ingenic. - Add documentation on how to test vkms. - Convert vc4 to atomic helpers. - Use degamma instead of gamma table in omap, to add support for CTM and color encoding/range properties. - Rework omap DSI code, and merge all omapdrm modules now that the last omap panel is now a drm panel. - More refactoring of omap dsi code. - Enable 10/12 bpc outputs in vc4. Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/78381a4f-45fd-aed4-174a-94ba051edd37@linux.intel.com
Diffstat (limited to 'drivers/dma-buf')
-rw-r--r--drivers/dma-buf/dma-buf.c74
1 files changed, 52 insertions, 22 deletions
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index e63684d4cd90..b8465243eca2 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -480,7 +480,7 @@ err_alloc_file:
*
* 4. Once a driver is done with a shared buffer it needs to call
* dma_buf_detach() (after cleaning up any mappings) and then release the
- * reference acquired with dma_buf_get by calling dma_buf_put().
+ * reference acquired with dma_buf_get() by calling dma_buf_put().
*
* For the detailed semantics exporters are expected to implement see
* &dma_buf_ops.
@@ -496,9 +496,10 @@ err_alloc_file:
* by the exporter. see &struct dma_buf_export_info
* for further details.
*
- * Returns, on success, a newly created dma_buf object, which wraps the
- * supplied private data and operations for dma_buf_ops. On either missing
- * ops, or error in allocating struct dma_buf, will return negative error.
+ * Returns, on success, a newly created struct dma_buf object, which wraps the
+ * supplied private data and operations for struct dma_buf_ops. On either
+ * missing ops, or error in allocating struct dma_buf, will return negative
+ * error.
*
* For most cases the easiest way to create @exp_info is through the
* %DEFINE_DMA_BUF_EXPORT_INFO macro.
@@ -584,7 +585,7 @@ err_module:
EXPORT_SYMBOL_GPL(dma_buf_export);
/**
- * dma_buf_fd - returns a file descriptor for the given dma_buf
+ * dma_buf_fd - returns a file descriptor for the given struct dma_buf
* @dmabuf: [in] pointer to dma_buf for which fd is required.
* @flags: [in] flags to give to fd
*
@@ -608,10 +609,10 @@ int dma_buf_fd(struct dma_buf *dmabuf, int flags)
EXPORT_SYMBOL_GPL(dma_buf_fd);
/**
- * dma_buf_get - returns the dma_buf structure related to an fd
- * @fd: [in] fd associated with the dma_buf to be returned
+ * dma_buf_get - returns the struct dma_buf related to an fd
+ * @fd: [in] fd associated with the struct dma_buf to be returned
*
- * On success, returns the dma_buf structure associated with an fd; uses
+ * On success, returns the struct dma_buf associated with an fd; uses
* file's refcounting done by fget to increase refcount. returns ERR_PTR
* otherwise.
*/
@@ -653,8 +654,7 @@ void dma_buf_put(struct dma_buf *dmabuf)
EXPORT_SYMBOL_GPL(dma_buf_put);
/**
- * dma_buf_dynamic_attach - Add the device to dma_buf's attachments list; optionally,
- * calls attach() of dma_buf_ops to allow device-specific attach functionality
+ * dma_buf_dynamic_attach - Add the device to dma_buf's attachments list
* @dmabuf: [in] buffer to attach device to.
* @dev: [in] device to be attached.
* @importer_ops: [in] importer operations for the attachment
@@ -663,6 +663,9 @@ EXPORT_SYMBOL_GPL(dma_buf_put);
* Returns struct dma_buf_attachment pointer for this attachment. Attachments
* must be cleaned up by calling dma_buf_detach().
*
+ * Optionally this calls &dma_buf_ops.attach to allow device-specific attach
+ * functionality.
+ *
* Returns:
*
* A pointer to newly created &dma_buf_attachment on success, or a negative
@@ -769,12 +772,13 @@ struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
EXPORT_SYMBOL_GPL(dma_buf_attach);
/**
- * dma_buf_detach - Remove the given attachment from dmabuf's attachments list;
- * optionally calls detach() of dma_buf_ops for device-specific detach
+ * dma_buf_detach - Remove the given attachment from dmabuf's attachments list
* @dmabuf: [in] buffer to detach from.
* @attach: [in] attachment to be detached; is free'd after this call.
*
* Clean up a device attachment obtained by calling dma_buf_attach().
+ *
+ * Optionally this calls &dma_buf_ops.detach for device-specific detach.
*/
void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
{
@@ -805,9 +809,15 @@ EXPORT_SYMBOL_GPL(dma_buf_detach);
/**
* dma_buf_pin - Lock down the DMA-buf
- *
* @attach: [in] attachment which should be pinned
*
+ * Only dynamic importers (who set up @attach with dma_buf_dynamic_attach()) may
+ * call this, and only for limited use cases like scanout and not for temporary
+ * pin operations. It is not permitted to allow userspace to pin arbitrary
+ * amounts of buffers through this interface.
+ *
+ * Buffers must be unpinned by calling dma_buf_unpin().
+ *
* Returns:
* 0 on success, negative error code on failure.
*/
@@ -816,6 +826,8 @@ int dma_buf_pin(struct dma_buf_attachment *attach)
struct dma_buf *dmabuf = attach->dmabuf;
int ret = 0;
+ WARN_ON(!dma_buf_attachment_is_dynamic(attach));
+
dma_resv_assert_held(dmabuf->resv);
if (dmabuf->ops->pin)
@@ -826,14 +838,19 @@ int dma_buf_pin(struct dma_buf_attachment *attach)
EXPORT_SYMBOL_GPL(dma_buf_pin);
/**
- * dma_buf_unpin - Remove lock from DMA-buf
- *
+ * dma_buf_unpin - Unpin a DMA-buf
* @attach: [in] attachment which should be unpinned
+ *
+ * This unpins a buffer pinned by dma_buf_pin() and allows the exporter to move
+ * any mapping of @attach again and inform the importer through
+ * &dma_buf_attach_ops.move_notify.
*/
void dma_buf_unpin(struct dma_buf_attachment *attach)
{
struct dma_buf *dmabuf = attach->dmabuf;
+ WARN_ON(!dma_buf_attachment_is_dynamic(attach));
+
dma_resv_assert_held(dmabuf->resv);
if (dmabuf->ops->unpin)
@@ -1001,15 +1018,15 @@ EXPORT_SYMBOL_GPL(dma_buf_move_notify);
* vmalloc space might be limited and result in vmap calls failing.
*
* Interfaces::
+ *
* void \*dma_buf_vmap(struct dma_buf \*dmabuf)
* 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. 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.
+ * it runs out of vmalloc space. 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.
*
* - For full compatibility on the importer side with existing userspace
* interfaces, which might already support mmap'ing buffers. This is needed in
@@ -1061,11 +1078,12 @@ EXPORT_SYMBOL_GPL(dma_buf_move_notify);
* shootdowns would increase the complexity quite a bit.
*
* Interface::
+ *
* int dma_buf_mmap(struct dma_buf \*, struct vm_area_struct \*,
* unsigned long);
*
* If the importing subsystem simply provides a special-purpose mmap call to
- * set up a mapping in userspace, calling do_mmap with dma_buf->file will
+ * set up a mapping in userspace, calling do_mmap with &dma_buf.file will
* equally achieve that for a dma-buf object.
*/
@@ -1098,6 +1116,11 @@ static int __dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
* dma_buf_end_cpu_access(). Only when cpu access is braketed by both calls is
* it guaranteed to be coherent with other DMA access.
*
+ * This function will also wait for any DMA transactions tracked through
+ * implicit synchronization in &dma_buf.resv. For DMA transactions with explicit
+ * synchronization this function will only ensure cache coherency, callers must
+ * ensure synchronization with such DMA transactions on their own.
+ *
* Can return negative error values, returns 0 on success.
*/
int dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
@@ -1108,6 +1131,8 @@ int dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
if (WARN_ON(!dmabuf))
return -EINVAL;
+ might_lock(&dmabuf->resv->lock.base);
+
if (dmabuf->ops->begin_cpu_access)
ret = dmabuf->ops->begin_cpu_access(dmabuf, direction);
@@ -1141,6 +1166,8 @@ int dma_buf_end_cpu_access(struct dma_buf *dmabuf,
WARN_ON(!dmabuf);
+ might_lock(&dmabuf->resv->lock.base);
+
if (dmabuf->ops->end_cpu_access)
ret = dmabuf->ops->end_cpu_access(dmabuf, direction);
@@ -1199,7 +1226,10 @@ EXPORT_SYMBOL_GPL(dma_buf_mmap);
* 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.
+ *
+ * To ensure coherency users must call dma_buf_begin_cpu_access() and
+ * dma_buf_end_cpu_access() around any cpu access performed through this
+ * mapping.
*
* Returns 0 on success, or a negative errno code otherwise.
*/