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* dma-buf: Add debugfs supportSumit Semwal2013-05-011-0/+158
| | | | | | | | | | | Add debugfs support to make it easier to print debug information about the dma-buf buffers. Cc: Dave Airlie <airlied@redhat.com> [minor fixes on init and warning fix] Cc: Dan Carpenter <dan.carpenter@oracle.com> [remove double unlock in fail case] Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
* dma-buf: replace dma_buf_export() with dma_buf_export_named()Sumit Semwal2013-05-011-4/+7
| | | | | | | | | | | | | | | | For debugging purposes, it is useful to have a name-string added while exporting buffers. Hence, dma_buf_export() is replaced with dma_buf_export_named(), which additionally takes 'exp_name' as a parameter. For backward compatibility, and for lazy exporters who don't wish to name themselves, a #define dma_buf_export() is also made available, which adds a __FILE__ instead of 'exp_name'. Cc: Daniel Vetter <daniel.vetter@ffwll.ch> [Thanks for the idea!] Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
* CHROMIUM: dma-buf: restore args on failure of dma_buf_mmapJohn Sheu2013-02-271-6/+17
| | | | | | | | | | Callers to dma_buf_mmap expect to fput() the vma struct's vm_file themselves on failure. Not restoring the struct's data on failure causes a double-decrement of the vm_file's refcount. Signed-off-by: John Sheu <sheu@google.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
* dma-buf: implement vmap refcounting in the interface logicDaniel Vetter2013-02-271-5/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | All drivers which implement this need to have some sort of refcount to allow concurrent vmap usage. Hence implement this in the dma-buf core. To protect against concurrent calls we need a lock, which potentially causes new funny locking inversions. But this shouldn't be a problem for exporters with statically allocated backing storage, and more dynamic drivers have decent issues already anyway. Inspired by some refactoring patches from Aaron Plattner, who implemented the same idea, but only for drm/prime drivers. v2: Check in dma_buf_release that no dangling vmaps are left. Suggested by Aaron Plattner. We might want to do similar checks for attachments, but that's for another patch. Also fix up ERR_PTR return for vmap. v3: Check whether the passed-in vmap address matches with the cached one for vunmap. Eventually we might want to remove that parameter - compared to the kmap functions there's no need for the vaddr for unmapping. Suggested by Chris Wilson. v4: Fix a brown-paper-bag bug spotted by Aaron Plattner. Cc: Aaron Plattner <aplattner@nvidia.com> Reviewed-by: Aaron Plattner <aplattner@nvidia.com> Tested-by: Aaron Plattner <aplattner@nvidia.com> Reviewed-by: Rob Clark <rob@ti.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
* dma_buf: Cleanup dma_buf_fdBorislav Petkov2013-01-171-5/+4
| | | | | | | Remove redundant 'error' variable. Signed-off-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* dma-buf: might_sleep() in dma_buf_unmap_attachment()Rob Clark2012-12-201-0/+2
| | | | | | | | | | | | We never really clarified if unmap could be done in atomic context. But since mapping might require sleeping, this implies mutex in use to synchronize mapping/unmapping, so unmap could sleep as well. Add a might_sleep() to clarify this. Signed-off-by: Rob Clark <rob@ti.com> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
* make get_file() return its argumentAl Viro2012-09-261-2/+1
| | | | | | simplifies a bunch of callers... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* driver core: fix some kernel-doc warnings in dma*.cRandy Dunlap2012-06-141-0/+1
| | | | | | | | | | Fix kernel-doc warnings in drivers/base/dma*.c: Warning(drivers/base/dma-buf.c:498): No description found for parameter 'vaddr' Warning(drivers/base/dma-coherent.c:199): No description found for parameter 'ret' Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge tag 'tag-for-linus-3.5' of ↵Linus Torvalds2012-05-251-1/+98
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.linaro.org/people/sumitsemwal/linux-dma-buf Pull dma-buf updates from Sumit Semwal: "Here's the first signed-tag pull request for dma-buf framework. It includes the following key items: - mmap support - vmap support - related documentation updates These are needed by various drivers to allow mmap/vmap of dma-buf shared buffers. Dave Airlie has some prime patches dependent on the vmap pull as well." * tag 'tag-for-linus-3.5' of git://git.linaro.org/people/sumitsemwal/linux-dma-buf: dma-buf: add initial vmap documentation dma-buf: minor documentation fixes. dma-buf: add vmap interface dma-buf: mmap support
| * dma-buf: minor documentation fixes.Sumit Semwal2012-05-251-4/+5
| | | | | | | | | | | | | | Some minor inline documentation fixes for gaps resulting from new patches. Signed-off-by: Sumit Semwal <sumit.semwal@ti.com> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
| * dma-buf: add vmap interfaceDave Airlie2012-05-251-0/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The main requirement I have for this interface is for scanning out using the USB gpu devices. Since these devices have to read the framebuffer on updates and linearly compress it, using kmaps is a major overhead for every update. v2: fix warn issues pointed out by Sylwester Nawrocki. v3: fix compile !CONFIG_DMA_SHARED_BUFFER and add _GPL for now Signed-off-by: Dave Airlie <airlied@redhat.com> Reviewed-by: Rob Clark <rob.clark@linaro.org> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
| * dma-buf: mmap supportDaniel Vetter2012-05-251-1/+63
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Compared to Rob Clark's RFC I've ditched the prepare/finish hooks and corresponding ioctls on the dma_buf file. The major reason for that is that many people seem to be under the impression that this is also for synchronization with outstanding asynchronous processsing. I'm pretty massively opposed to this because: - It boils down reinventing a new rather general-purpose userspace synchronization interface. If we look at things like futexes, this is hard to get right. - Furthermore a lot of kernel code has to interact with this synchronization primitive. This smells a look like the dri1 hw_lock, a horror show I prefer not to reinvent. - Even more fun is that multiple different subsystems would interact here, so we have plenty of opportunities to create funny deadlock scenarios. I think synchronization is a wholesale different problem from data sharing and should be tackled as an orthogonal problem. Now we could demand that prepare/finish may only ensure cache coherency (as Rob intended), but that runs up into the next problem: We not only need mmap support to facilitate sw-only processing nodes in a pipeline (without jumping through hoops by importing the dma_buf into some sw-access only importer), which allows for a nicer ION->dma-buf upgrade path for existing Android userspace. We also need mmap support for existing importing subsystems to support existing userspace libraries. And a loot of these subsystems are expected to export coherent userspace mappings. So prepare/finish can only ever be optional and the exporter /needs/ to support coherent mappings. Given that mmap access is always somewhat fallback-y in nature I've decided to drop this optimization, instead of just making it optional. If we demonstrate a clear need for this, supported by benchmark results, we can always add it in again later as an optional extension. Other differences compared to Rob's RFC is the above mentioned support for mapping a dma-buf through facilities provided by the importer. Which results in mmap support no longer being optional. Note that this dma-buf mmap patch does _not_ support every possible insanity an existing subsystem could pull of with mmap: Because it does not allow to intercept pagefaults and shoot down ptes importing subsystems can't add some magic of their own at these points (e.g. to automatically synchronize with outstanding rendering or set up some special resources). I've done a cursory read through a few mmap implementions of various subsytems and I'm hopeful that we can avoid this (and the complexity it'd bring with it). Additonally I've extended the documentation a bit to explain the hows and whys of this mmap extension. In case we ever want to add support for explicitly cache maneged userspace mmap with a prepare/finish ioctl pair, we could specify that userspace needs to mmap a different part of the dma_buf, e.g. the range starting at dma_buf->size up to dma_buf->size*2. This works because the size of a dma_buf is invariant over it's lifetime. The exporter would obviously need to fall back to coherent mappings for both ranges if a legacy clients maps the coherent range and the architecture cannot suppor conflicting caching policies. Also, this would obviously be optional and userspace needs to be able to fall back to coherent mappings. v2: - Spelling fixes from Rob Clark. - Compile fix for !DMA_BUF from Rob Clark. - Extend commit message to explain how explicitly cache managed mmap support could be added later. - Extend the documentation with implementations notes for exporters that need to manually fake coherency. v3: - dma_buf pointer initialization goof-up noticed by Rebecca Schultz Zavin. Cc: Rob Clark <rob.clark@linaro.org> Cc: Rebecca Schultz Zavin <rebecca@android.com> Acked-by: Rob Clark <rob.clark@linaro.org> Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
* | driver core: fix dma-buf.c kernel-doc warningsRandy Dunlap2012-04-181-6/+6
|/ | | | | | | | | | | | | | | | | | | | Fix kernel-doc warnings in dma-buf.c: Warning(drivers/base/dma-buf.c:305): No description found for parameter 'dmabuf' Warning(drivers/base/dma-buf.c:305): Excess function parameter 'dma_buf' description in 'dma_buf_begin_cpu_access' Warning(drivers/base/dma-buf.c:332): No description found for parameter 'dmabuf' Warning(drivers/base/dma-buf.c:332): Excess function parameter 'dma_buf' description in 'dma_buf_end_cpu_access' Warning(drivers/base/dma-buf.c:350): No description found for parameter 'dmabuf' Warning(drivers/base/dma-buf.c:350): Excess function parameter 'dma_buf' description in 'dma_buf_kmap_atomic' Warning(drivers/base/dma-buf.c:367): No description found for parameter 'dmabuf' Warning(drivers/base/dma-buf.c:367): Excess function parameter 'dma_buf' description in 'dma_buf_kunmap_atomic' Warning(drivers/base/dma-buf.c:385): No description found for parameter 'dmabuf' Warning(drivers/base/dma-buf.c:385): Excess function parameter 'dma_buf' description in 'dma_buf_kmap' Warning(drivers/base/dma-buf.c:402): No description found for parameter 'dmabuf' Warning(drivers/base/dma-buf.c:402): Excess function parameter 'dma_buf' description in 'dma_buf_kunmap' Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* dma-buf: add support for kernel cpu accessDaniel Vetter2012-03-261-1/+123
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Big differences to other contenders in the field (like ion) is that this also supports highmem, so we have to split up the cpu access from the kernel side into a prepare and a kmap step. Prepare is allowed to fail and should do everything required so that the kmap calls can succeed (like swapin/backing storage allocation, flushing, ...). More in-depth explanations will follow in the follow-up documentation patch. Changes in v2: - Clear up begin_cpu_access confusion noticed by Sumit Semwal. - Don't automatically fallback from the _atomic variants to the non-atomic variants. The _atomic callbacks are not allowed to sleep, so we want exporters to make this decision explicit. The function signatures are explicit, so simpler exporters can still use the same function for both. - Make the unmap functions optional. Simpler exporters with permanent mappings don't need to do anything at unmap time. Changes in v3: - Adjust the WARN_ON checks for the new ->ops functions as suggested by Rob Clark and Sumit Semwal. - Rebased on top of latest dma-buf-next git. Changes in v4: - Fixup a missing - in a return -EINVAL; statement. Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Rob Clark <rob@ti.com> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
* dma-buf: don't hold the mutex around map/unmap callsDaniel Vetter2012-03-261-5/+0
| | | | | | | | | | | | | | | | | | | The mutex protects the attachment list and hence needs to be held around the callbakc to the exporters (optional) attach/detach functions. Holding the mutex around the map/unmap calls doesn't protect any dma_buf state. Exporters need to properly protect any of their own state anyway (to protect against calls from their own interfaces). So this only makes the locking messier (and lockdep easier to anger). Therefore let's just drop this. v2: Rebased on top of latest dma-buf-next git. Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Rob Clark <rob.clark@linaro.org> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
* dma-buf: pass flags into dma_buf_fd.Dave Airlie2012-03-261-2/+3
| | | | | | | | | We need to pass the flags into dma_buf_fd at this point, so the flags end up doing the right thing for O_CLOEXEC. Signed-off-by: Dave Airlie <airlied@redhat.com> Signed-off-by: Rob Clark <rob@ti.com> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
* dma-buf: add dma_data_direction to unmap dma_buf_opSumit Semwal2012-03-261-2/+5
| | | | | | | | | | | | | Some exporters may use DMA map/unmap APIs in dma-buf ops, which require enum dma_data_direction for both map and unmap operations. Thus, the unmap dma_buf_op also needs to have enum dma_data_direction as a parameter. Reported-by: Tomasz Stanislawski <t.stanislaws@samsung.com> Signed-off-by: Sumit Semwal <sumit.semwal@ti.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
* dma-buf: Move code out of mutex-protected section in dma_buf_attach()Laurent Pinchart2012-03-191-2/+3
| | | | | | | | | Some fields can be set without mutex protection. Initialize them before locking the mutex. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
* dma-buf: Return error instead of using a goto statement when possibleLaurent Pinchart2012-03-191-3/+1
| | | | | | | | | Remove an error label in dma_buf_attach() that just returns an error code. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
* dma-buf: Remove unneeded sanity checksLaurent Pinchart2012-03-191-9/+6
| | | | | | | | | | ops, ops->map_dma_buf and ops->unmap_dma_buf are guaranteed to be non-NULL by a check in dma_buf_export(). Remove NULL checks on those variables in the other API functions. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
* dma-buf: Constify ops argument to dma_buf_export()Laurent Pinchart2012-03-191-1/+1
| | | | | | | | This allows drivers to make the dma buf operations structure constant. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
* dma-buf: Introduce dma buffer sharing mechanismSumit Semwal2012-01-061-0/+291
This is the first step in defining a dma buffer sharing mechanism. A new buffer object dma_buf is added, with operations and API to allow easy sharing of this buffer object across devices. The framework allows: - creation of a buffer object, its association with a file pointer, and associated allocator-defined operations on that buffer. This operation is called the 'export' operation. - different devices to 'attach' themselves to this exported buffer object, to facilitate backing storage negotiation, using dma_buf_attach() API. - the exported buffer object to be shared with the other entity by asking for its 'file-descriptor (fd)', and sharing the fd across. - a received fd to get the buffer object back, where it can be accessed using the associated exporter-defined operations. - the exporter and user to share the scatterlist associated with this buffer object using map_dma_buf and unmap_dma_buf operations. Atleast one 'attach()' call is required to be made prior to calling the map_dma_buf() operation. Couple of building blocks in map_dma_buf() are added to ease introduction of sync'ing across exporter and users, and late allocation by the exporter. For this first version, this framework will work with certain conditions: - *ONLY* exporter will be allowed to mmap to userspace (outside of this framework - mmap is not a buffer object operation), - currently, *ONLY* users that do not need CPU access to the buffer are allowed. More details are there in the documentation patch. This is based on design suggestions from many people at the mini-summits[1], most notably from Arnd Bergmann <arnd@arndb.de>, Rob Clark <rob@ti.com> and Daniel Vetter <daniel@ffwll.ch>. The implementation is inspired from proof-of-concept patch-set from Tomasz Stanislawski <t.stanislaws@samsung.com>, who demonstrated buffer sharing between two v4l2 devices. [2] [1]: https://wiki.linaro.org/OfficeofCTO/MemoryManagement [2]: http://lwn.net/Articles/454389 Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org> Signed-off-by: Sumit Semwal <sumit.semwal@ti.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Dave Airlie <airlied@redhat.com> Reviewed-and-Tested-by: Rob Clark <rob.clark@linaro.org> Signed-off-by: Dave Airlie <airlied@redhat.com>
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