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author | Daniel Vetter <daniel.vetter@ffwll.ch> | 2021-01-07 10:46:32 +0100 |
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committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2021-01-07 10:46:32 +0100 |
commit | 18589d74f45d6af7e7614b6488543d723ebf236a (patch) | |
tree | a735d6ed4ea46926766d981c3944651fb78e2dc6 /drivers/dma-buf | |
parent | Linux 5.11-rc2 (diff) | |
parent | dma-buf: doc polish for pin/unpin (diff) | |
download | linux-18589d74f45d6af7e7614b6488543d723ebf236a.tar.xz linux-18589d74f45d6af7e7614b6488543d723ebf236a.zip |
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.c | 74 |
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. */ |