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2020-11-11dma-buf: Document that dma-buf size is fixedJianxin Xiong1-2/+2
The fact that the size of dma-buf is invariant over the lifetime of the buffer is mentioned in the comment of 'dma_buf_ops.mmap', but is not documented at where the info is defined. Add the missing documentation. Signed-off-by: Jianxin Xiong <jianxin.xiong@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/1605044477-51833-7-git-send-email-jianxin.xiong@intel.com
2020-10-15dma-buf: Clarify that dma-buf sg lists are page alignedJianxin Xiong1-1/+2
The dma-buf API have been used under the assumption that the sg lists returned from dma_buf_map_attachment() are fully page aligned. Lots of stuff can break otherwise all over the place. Clarify this in the documentation and add a check when DMA API debug is enabled. Signed-off-by: Jianxin Xiong <jianxin.xiong@intel.com> Reviewed-by: Christian König <christian.koenig@amd.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/1602692161-107096-1-git-send-email-jianxin.xiong@intel.com
2020-09-29dma-buf: Use struct dma_buf_map in dma_buf_vunmap() interfacesThomas Zimmermann1-2/+2
This patch updates dma_buf_vunmap() and dma-buf's vunmap callback to use struct dma_buf_map. The interfaces used to receive a buffer address. This address is now given in an instance of the structure. Users of the functions are updated accordingly. This is only an interface change. It is currently expected that dma-buf memory can be accessed with system memory load/store operations. v2: * include dma-buf-heaps and i915 selftests (kernel test robot) * initialize cma_obj before using it in drm_gem_cma_free_object() (kernel test robot) Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Acked-by: Sumit Semwal <sumit.semwal@linaro.org> Acked-by: Christian König <christian.koenig@amd.com> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Acked-by: Tomasz Figa <tfiga@chromium.org> Acked-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/20200925115601.23955-4-tzimmermann@suse.de
2020-09-29dma-buf: Use struct dma_buf_map in dma_buf_vmap() interfacesThomas Zimmermann1-3/+3
This patch updates dma_buf_vmap() and dma-buf's vmap callback to use struct dma_buf_map. The interfaces used to return a buffer address. This address now gets stored in an instance of the structure that is given as an additional argument. The functions return an errno code on errors. Users of the functions are updated accordingly. This is only an interface change. It is currently expected that dma-buf memory can be accessed with system memory load/store operations. v3: * update fastrpc driver (kernel test robot) v2: * always clear map parameter in dma_buf_vmap() (Daniel) * include dma-buf-heaps and i915 selftests (kernel test robot) Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Acked-by: Sumit Semwal <sumit.semwal@linaro.org> Acked-by: Christian König <christian.koenig@amd.com> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Acked-by: Tomasz Figa <tfiga@chromium.org> Acked-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/20200925115601.23955-3-tzimmermann@suse.de
2020-09-29dma-buf: Add struct dma-buf-map for storing struct dma_buf.vaddr_ptrThomas Zimmermann1-1/+2
The new type struct dma_buf_map represents a mapping of dma-buf memory into kernel space. It contains a flag, is_iomem, that signals users to access the mapped memory with I/O operations instead of regular loads and stores. It was assumed that DMA buffer memory can be accessed with regular load and store operations. Some architectures, such as sparc64, require the use of I/O operations to access dma-map buffers that are located in I/O memory. Providing struct dma_buf_map allows drivers to implement this. This was specifically a problem when refreshing the graphics framebuffer on such systems. [1] As the first step, struct dma_buf stores an instance of struct dma_buf_map internally. Afterwards, dma-buf's vmap and vunmap interfaces are be converted. Finally, affected drivers can be fixed. v3: * moved documentation into separate patch * test for NULL pointers with !<ptr> [1] https://lore.kernel.org/dri-devel/20200725191012.GA434957@ravnborg.org/ Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Christian König <christian.koenig@amd.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Acked-by: Sumit Semwal <sumit.semwal@linaro.org> Acked-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/20200925115601.23955-2-tzimmermann@suse.de
2020-09-02dma-buf: fix kernel-doc warning in <linux/dma-buf.h>Randy Dunlap1-1/+2
Fix kernel-doc warning in <linux/dma-buf.h>: ../include/linux/dma-buf.h:330: warning: Function parameter or member 'name_lock' not described in 'dma_buf' Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Gustavo Padovan <gustavo@padovan.org> Cc: Christian König <christian.koenig@amd.com> Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Reviewed-by: Christian König <christian.koenig@amd.com> Link: https://patchwork.freedesktop.org/patch/388523/ Signed-off-by: Christian König <christian.koenig@amd.com>
2020-07-10dmabuf: use spinlock to access dmabuf->nameCharan Teja Kalla1-0/+1
There exists a sleep-while-atomic bug while accessing the dmabuf->name under mutex in the dmabuffs_dname(). This is caused from the SELinux permissions checks on a process where it tries to validate the inherited files from fork() by traversing them through iterate_fd() (which traverse files under spin_lock) and call match_file(security/selinux/hooks.c) where the permission checks happen. This audit information is logged using dump_common_audit_data() where it calls d_path() to get the file path name. If the file check happen on the dmabuf's fd, then it ends up in ->dmabuffs_dname() and use mutex to access dmabuf->name. The flow will be like below: flush_unauthorized_files() iterate_fd() spin_lock() --> Start of the atomic section. match_file() file_has_perm() avc_has_perm() avc_audit() slow_avc_audit() common_lsm_audit() dump_common_audit_data() audit_log_d_path() d_path() dmabuffs_dname() mutex_lock()--> Sleep while atomic. Call trace captured (on 4.19 kernels) is below: ___might_sleep+0x204/0x208 __might_sleep+0x50/0x88 __mutex_lock_common+0x5c/0x1068 __mutex_lock_common+0x5c/0x1068 mutex_lock_nested+0x40/0x50 dmabuffs_dname+0xa0/0x170 d_path+0x84/0x290 audit_log_d_path+0x74/0x130 common_lsm_audit+0x334/0x6e8 slow_avc_audit+0xb8/0xf8 avc_has_perm+0x154/0x218 file_has_perm+0x70/0x180 match_file+0x60/0x78 iterate_fd+0x128/0x168 selinux_bprm_committing_creds+0x178/0x248 security_bprm_committing_creds+0x30/0x48 install_exec_creds+0x1c/0x68 load_elf_binary+0x3a4/0x14e0 search_binary_handler+0xb0/0x1e0 So, use spinlock to access dmabuf->name to avoid sleep-while-atomic. Cc: <stable@vger.kernel.org> [5.3+] Signed-off-by: Charan Teja Kalla <charante@codeaurora.org> Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com> Acked-by: Christian König <christian.koenig@amd.com> [sumits: added comment to spinlock_t definition to avoid warning] Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org> Link: https://patchwork.freedesktop.org/patch/msgid/a83e7f0d-4e54-9848-4b58-e1acdbe06735@codeaurora.org
2020-06-02Merge tag 'drm-next-2020-06-02' of git://anongit.freedesktop.org/drm/drmLinus Torvalds1-0/+10
Pull drm updates from Dave Airlie: "Highlights: - Core DRM had a lot of refactoring around managed drm resources to make drivers simpler. - Intel Tigerlake support is on by default - amdgpu now support p2p PCI buffer sharing and encrypted GPU memory Details: core: - uapi: error out EBUSY when existing master - uapi: rework SET/DROP MASTER permission handling - remove drm_pci.h - drm_pci* are now legacy - introduced managed DRM resources - subclassing support for drm_framebuffer - simple encoder helper - edid improvements - vblank + writeback documentation improved - drm/mm - optimise tree searches - port drivers to use devm_drm_dev_alloc dma-buf: - add flag for p2p buffer support mst: - ACT timeout improvements - remove drm_dp_mst_has_audio - don't use 2nd TX slot - spec recommends against it bridge: - dw-hdmi various improvements - chrontel ch7033 support - fix stack issues with old gcc hdmi: - add unpack function for drm infoframe fbdev: - misc fbdev driver fixes i915: - uapi: global sseu pinning - uapi: OA buffer polling - uapi: remove generated perf code - uapi: per-engine default property values in sysfs - Tigerlake GEN12 enabled. - Lots of gem refactoring - Tigerlake enablement patches - move to drm_device logging - Icelake gamma HW readout - push MST link retrain to hotplug work - bandwidth atomic helpers - ICL fixes - RPS/GT refactoring - Cherryview full-ppgtt support - i915 locking guidelines documented - require linear fb stride to be 512 multiple on gen9 - Tigerlake SAGV support amdgpu: - uapi: encrypted GPU memory handling - uapi: add MEM_SYNC IB flag - p2p dma-buf support - export VRAM dma-bufs - FRU chip access support - RAS/SR-IOV updates - Powerplay locking fixes - VCN DPG (powergating) enablement - GFX10 clockgating fixes - DC fixes - GPU reset fixes - navi SDMA fix - expose FP16 for modesetting - DP 1.4 compliance fixes - gfx10 soft recovery - Improved Critical Thermal Faults handling - resizable BAR on gmc10 amdkfd: - uapi: GWS resource management - track GPU memory per process - report PCI domain in topology radeon: - safe reg list generator fixes nouveau: - HD audio fixes on recent systems - vGPU detection (fail probe if we're on one, for now) - Interlaced mode fixes (mostly avoidance on Turing, which doesn't support it) - SVM improvements/fixes - NVIDIA format modifier support - Misc other fixes. adv7511: - HDMI SPDIF support ast: - allocate crtc state size - fix double assignment - fix suspend bochs: - drop connector register cirrus: - move to tiny drivers. exynos: - fix imported dma-buf mapping - enable runtime PM - fixes and cleanups mediatek: - DPI pin mode swap - config mipi_tx current/impedance lima: - devfreq + cooling device support - task handling improvements - runtime PM support pl111: - vexpress init improvements - fix module auto-load rcar-du: - DT bindings conversion to YAML - Planes zpos sanity check and fix - MAINTAINERS entry for LVDS panel driver mcde: - fix return value mgag200: - use managed config init stm: - read endpoints from DT vboxvideo: - use PCI managed functions - drop WC mtrr vkms: - enable cursor by default rockchip: - afbc support virtio: - various cleanups qxl: - fix cursor notify port hisilicon: - 128-byte stride alignment fix sun4i: - improved format handling" * tag 'drm-next-2020-06-02' of git://anongit.freedesktop.org/drm/drm: (1401 commits) drm/amd/display: Fix potential integer wraparound resulting in a hang drm/amd/display: drop cursor position check in atomic test drm/amdgpu: fix device attribute node create failed with multi gpu drm/nouveau: use correct conflicting framebuffer API drm/vblank: Fix -Wformat compile warnings on some arches drm/amdgpu: Sync with VM root BO when switching VM to CPU update mode drm/amd/display: Handle GPU reset for DC block drm/amdgpu: add apu flags (v2) drm/amd/powerpay: Disable gfxoff when setting manual mode on picasso and raven drm/amdgpu: fix pm sysfs node handling (v2) drm/amdgpu: move gpu_info parsing after common early init drm/amdgpu: move discovery gfx config fetching drm/nouveau/dispnv50: fix runtime pm imbalance on error drm/nouveau: fix runtime pm imbalance on error drm/nouveau: fix runtime pm imbalance on error drm/nouveau/debugfs: fix runtime pm imbalance on error drm/nouveau/nouveau/hmm: fix migrate zero page to GPU drm/nouveau/nouveau/hmm: fix nouveau_dmem_chunk allocations drm/nouveau/kms/nv50-: Share DP SST mode_valid() handling with MST drm/nouveau/kms/nv50-: Move 8BPC limit for MST into nv50_mstc_get_modes() ...
2020-04-30dma-buf: fix documentation build warningsRandy Dunlap1-2/+1
Fix documentation warnings in dma-buf.[hc]: ../drivers/dma-buf/dma-buf.c:678: warning: Function parameter or member 'importer_ops' not described in 'dma_buf_dynamic_attach' ../drivers/dma-buf/dma-buf.c:678: warning: Function parameter or member 'importer_priv' not described in 'dma_buf_dynamic_attach' ../include/linux/dma-buf.h:339: warning: Incorrect use of kernel-doc format: * @move_notify Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org> Link: https://patchwork.freedesktop.org/patch/msgid/7bcbe6fe-0b4b-87da-d003-b68a26eb4cf0@infradead.org
2020-04-01dma-buf: add peer2peer flagChristian König1-0/+10
Add a peer2peer flag noting that the importer can deal with device resources which are not backed by pages. Signed-off-by: Christian König <christian.koenig@amd.com> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Acked-by: Sumit Semwal <sumit.semwal@linaro.org> Link: https://patchwork.freedesktop.org/patch/359286/
2020-02-27dma-buf: drop dynamic_mapping flagChristian König1-16/+5
Instead use the pin() callback to detect dynamic DMA-buf handling. Since amdgpu is now migrated it doesn't make much sense to keep the extra flag. Signed-off-by: Christian König <christian.koenig@amd.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/353997/?series=73646&rev=1
2020-02-27dma-buf: add dynamic DMA-buf handling v15Christian König1-11/+71
On the exporter side we add optional explicit pinning callbacks. Which are called when the importer doesn't implement dynamic handling, move notification or need the DMA-buf locked in place for its use case. On the importer side we add an optional move_notify callback. This callback is used by the exporter to inform the importers that their mappings should be destroyed as soon as possible. This allows the exporter to provide the mappings without the need to pin the backing store. v2: don't try to invalidate mappings when the callback is NULL, lock the reservation obj while using the attachments, add helper to set the callback v3: move flag for invalidation support into the DMA-buf, use new attach_info structure to set the callback v4: use importer_priv field instead of mangling exporter priv. v5: drop invalidation_supported flag v6: squash together with pin/unpin changes v7: pin/unpin takes an attachment now v8: nuke dma_buf_attachment_(map|unmap)_locked, everything is now handled backward compatible v9: always cache when export/importer don't agree on dynamic handling v10: minimal style cleanup v11: drop automatically re-entry avoidance v12: rename callback to move_notify v13: add might_lock in appropriate places v14: rebase on separated locking change v15: add EXPERIMENTAL flag, some more code comments Signed-off-by: Christian König <christian.koenig@amd.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/353993/?series=73646&rev=1
2019-11-26dma-buf: Remove kernel map/unmap hooksDaniel Vetter1-25/+0
All implementations are gone now. Acked-by: Sumit Semwal <sumit.semwal@linaro.org> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20191118103536.17675-16-daniel.vetter@ffwll.ch
2019-11-25dma-buf: Drop dma_buf_k(un)mapDaniel Vetter1-2/+0
It's unused. 10 years ago, back when 32bit was still fairly common and trying to not exhaust vmalloc space sounded like a worthwhile goal, adding these to dma_buf made sense. Reality is that they simply never caught on, and nowadays everyone who needs plenty of buffers will run in 64bit mode anyway. Also update the docs in this area to adjust them to reality. The actual hooks in dma_buf_ops will be removed once all the implementations are gone. Acked-by: Sumit Semwal <sumit.semwal@linaro.org> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20191118103536.17675-10-daniel.vetter@ffwll.ch
2019-10-24dma-buf: change DMA-buf locking convention v3Christian König1-6/+57
This patch is a stripped down version of the locking changes necessary to support dynamic DMA-buf handling. It adds a dynamic flag for both importers as well as exporters so that drivers can choose if they want the reservation object locked or unlocked during mapping of attachments. For compatibility between drivers we cache the DMA-buf mapping during attaching an importer as soon as exporter/importer disagree on the dynamic handling. Issues and solutions we considered: - We can't change all existing drivers, and existing improters have strong opinions about which locks they're holding while calling dma_buf_attachment_map/unmap. Exporters also have strong opinions about which locks they can acquire in their ->map/unmap callbacks, levaing no room for change. The solution to avoid this was to move the actual map/unmap out from this call, into the attach/detach callbacks, and cache the mapping. This works because drivers don't call attach/detach from deep within their code callchains (like deep in memory management code called from cs/execbuf ioctl), but directly from the fd2handle implementation. - The caching has some troubles on some soc drivers, which set other modes than DMA_BIDIRECTIONAL. We can't have 2 incompatible mappings, and we can't re-create the mapping at _map time due to the above locking fun. We very carefuly step around that by only caching at attach time if the dynamic mode between importer/expoert mismatches. - There's been quite some discussion on dma-buf mappings which need active cache management, which would all break down when caching, plus we don't have explicit flush operations on the attachment side. The solution to this was to shrug and keep the current discrepancy between what the dma-buf docs claim and what implementations do, with the hope that the begin/end_cpu_access hooks are good enough and that all necessary flushing to keep device mappings consistent will be done there. v2: cleanup set_name merge, improve kerneldoc v3: update commit message, kerneldoc and cleanup _debug_show() Signed-off-by: Christian König <christian.koenig@amd.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/336788/
2019-08-13dma-buf: rename reservation_object to dma_resvChristian König1-2/+2
Be more consistent with the naming of the other DMA-buf objects. Signed-off-by: Christian König <christian.koenig@amd.com> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Link: https://patchwork.freedesktop.org/patch/323401/
2019-07-15Merge tag 'drm-next-2019-07-16' of git://anongit.freedesktop.org/drm/drmLinus Torvalds1-10/+42
Pull drm updates from Dave Airlie: "The biggest thing in this is the AMD Navi GPU support, this again contains a bunch of header files that are large. These are the new AMD RX5700 GPUs that just recently became available. New drivers: - ST-Ericsson MCDE driver - Ingenic JZ47xx SoC UAPI change: - HDR source metadata property Core: - HDR inforframes and EDID parsing - drm hdmi infoframe unpacking - remove prime sg_table caching into dma-buf - New gem vram helpers to reduce driver code - Lots of drmP.h removal - reservation fencing fix - documentation updates - drm_fb_helper_connector removed - mode name command handler rewrite fbcon: - Remove the fbcon notifiers ttm: - forward progress fixes dma-buf: - make mmap call optional - debugfs refcount fixes - dma-fence free with pending signals fix - each dma-buf gets an inode Panels: - Lots of additional panel bindings amdgpu: - initial navi10 support - avoid hw reset - HDR metadata support - new thermal sensors for vega asics - RAS fixes - use HMM rather than MMU notifier - xgmi topology via kfd - SR-IOV fixes - driver reload fixes - DC use a core bpc attribute - Aux fixes for DC - Bandwidth calc updates for DC - Clock handling refactor - kfd VEGAM support vmwgfx: - Coherent memory support changes i915: - HDR Support - HDMI i2c link - Icelake multi-segmented gamma support - GuC firmware update - Mule Creek Canyon PCH support for EHL - EHL platform updtes - move i915.alpha_support to i915.force_probe - runtime PM refactoring - VBT parsing refactoring - DSI fixes - struct mutex dependency reduction - GEM code reorg mali-dp: - Komeda driver features msm: - dsi vs EPROBE_DEFER fixes - msm8998 snapdragon 835 support - a540 gpu support - mdp5 and dpu interconnect support exynos: - drmP.h removal tegra: - misc fixes tda998x: - audio support improvements - pixel repeated mode support - quantisation range handling corrections - HDMI vendor info fix armada: - interlace support fix - overlay/video plane register handling refactor - add gamma support rockchip: - RX3328 support panfrost: - expose perf counters via hidden ioctls vkms: - enumerate CRC sources list ast: - rework BO handling mgag200: - rework BO handling dw-hdmi: - suspend/resume support rcar-du: - R8A774A1 Soc Support - LVDS dual-link mode support - Additional formats - Misc fixes omapdrm: - DSI command mode display support stm - fb modifier support - runtime PM support sun4i: - use vmap ops vc4: - binner bo binding rework v3d: - compute shader support - resync/sync fixes - job management refactoring lima: - NULL pointer in irq handler fix - scheduler default timeout virtio: - fence seqno support - trace events bochs: - misc fixes tc458767: - IRQ/HDP handling sii902x: - HDMI audio support atmel-hlcdc: - misc fixes meson: - zpos support" * tag 'drm-next-2019-07-16' of git://anongit.freedesktop.org/drm/drm: (1815 commits) Revert "Merge branch 'vmwgfx-next' of git://people.freedesktop.org/~thomash/linux into drm-next" Revert "mm: adjust apply_to_pfn_range interface for dropped token." mm: adjust apply_to_pfn_range interface for dropped token. drm/amdgpu/navi10: add uclk activity sensor drm/amdgpu: properly guard the generic discovery code drm/amdgpu: add missing documentation on new module parameters drm/amdgpu: don't invalidate caches in RELEASE_MEM, only do the writeback drm/amd/display: avoid 64-bit division drm/amdgpu/psp11: simplify the ucode register logic drm/amdgpu: properly guard DC support in navi code drm/amd/powerplay: vega20: fix uninitialized variable use drm/amd/display: dcn20: include linux/delay.h amdgpu: make pmu support optional drm/amd/powerplay: Zero initialize current_rpm in vega20_get_fan_speed_percent drm/amd/powerplay: Zero initialize freq in smu_v11_0_get_current_clk_freq drm/amd/powerplay: Use memset to initialize metrics structs drm/amdgpu/mes10.1: Fix header guard drm/amd/powerplay: add temperature sensor support for navi10 drm/amdgpu: fix scheduler timeout calc drm/amdgpu: Prepare for hmm_range_register API change (v2) ...
2019-06-19treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234Thomas Gleixner1-12/+1
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not see http www gnu org licenses extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 503 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Enrico Weigelt <info@metux.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-14dma-buf: add DMA_BUF_SET_NAME ioctlsGreg Hackmann1-1/+4
This patch adds complimentary DMA_BUF_SET_NAME ioctls, which lets userspace processes attach a free-form name to each buffer. This information can be extremely helpful for tracking and accounting shared buffers. For example, on Android, we know what each buffer will be used for at allocation time: GL, multimedia, camera, etc. The userspace allocator can use DMA_BUF_SET_NAME to associate that information with the buffer, so we can later give developers a breakdown of how much memory they're allocating for graphics, camera, etc. Signed-off-by: Greg Hackmann <ghackmann@google.com> Signed-off-by: Chenbo Feng <fengc@google.com> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org> Link: https://patchwork.freedesktop.org/patch/msgid/20190613223408.139221-3-fengc@google.com
2019-05-22dma-buf: start caching of sg_table objects v2Christian König1-0/+13
To allow a smooth transition from pinning buffer objects to dynamic invalidation we first start to cache the sg_table for an attachment. v2: keep closer to the DRM implementation Signed-off-by: Christian König <christian.koenig@amd.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.kernel.org/patch/10943053/
2019-04-24dma-buf: Update [un]map documentation to match the other functionsAndrew F. Davis1-4/+25
Other function have inline documentation, a couple still have theirs at the top of the structure, update the docs and move them inline. Signed-off-by: Andrew F. Davis <afd@ti.com> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org> Link: https://patchwork.freedesktop.org/patch/msgid/20190321200957.16938-2-afd@ti.com
2019-04-24dma-buf: Remove leftover [un]map_atomic commentsAndrew F. Davis1-5/+0
The map_atomic/unmap_atomic callbacks have been removed, remove the related comments. Fixes: f664a5269542 ("dma-buf: remove kmap_atomic interface") Signed-off-by: Andrew F. Davis <afd@ti.com> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org> Link: https://patchwork.freedesktop.org/patch/msgid/20190321200957.16938-1-afd@ti.com
2018-06-20dma-buf: remove kmap_atomic interfaceChristian König1-4/+0
Neither used nor correctly implemented anywhere. Just completely remove the interface. Signed-off-by: Christian König <christian.koenig@amd.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Acked-by: Sumit Semwal <sumit.semwal@linaro.org> Link: https://patchwork.freedesktop.org/patch/226645/
2018-06-20dma_buf: remove device parameter from attach callback v2Christian König1-7/+6
The device parameter is completely unused because it is available in the attachment structure as well. v2: fix kerneldoc as well Signed-off-by: Christian König <christian.koenig@amd.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/226643/
2018-06-01dma-buf: make map_atomic and map function pointers optionalGerd Hoffmann1-2/+2
So drivers don't need dummy functions just returning NULL. Cc: Daniel Vetter <daniel@ffwll.ch> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> Link: http://patchwork.freedesktop.org/patch/msgid/20180529135918.19729-1-kraxel@redhat.com
2017-11-27dmabuf: annotate dma_buf->activeAl Viro1-1/+1
Contains POLL... bitmaps Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-04-20dma-buf: Rename dma-ops to prevent conflict with kunmap_atomic macroLogan Gunthorpe1-11/+11
Seeing the kunmap_atomic dma_buf_ops share the same name with a macro in highmem.h, the former can be aliased if any dma-buf user includes that header. I'm personally trying to include highmem.h inside scatterlist.h and this breaks the dma-buf code proper. Christoph Hellwig suggested [1] renaming it and pushing this patch ASAP. To maintain consistency I've renamed all four of kmap* and kunmap* to be map* and unmap*. (Even though only kmap_atomic presently conflicts.) [1] https://www.spinics.net/lists/target-devel/msg15070.html Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Reviewed-by: Sinclair Yeh <syeh@vmware.com> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Acked-by: Sumit Semwal <sumit.semwal@linaro.org> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org> Link: http://patchwork.freedesktop.org/patch/msgid/1492630570-879-1-git-send-email-logang@deltatee.com
2016-12-30dma-buf: Use recommended structure member referenceDaniel Vetter1-3/+3
I just learned that &struct_name.member_name works and looks pretty even. It doesn't (yet) link to the member directly though, which would be really good for big structures or vfunc tables (where the per-member kerneldoc tends to be long). Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: David Herrmann <dh.herrmann@gmail.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1483044517-5770-5-git-send-email-daniel.vetter@ffwll.ch
2016-12-30dma-buf: use preferred struct reference in kernel-docDaniel Vetter1-2/+2
sed -e 's/\( \* .*\)struct &\([_a-z]*\)/\1\&struct \2/' -i Originally I wasnt a friend of this style because I thought a line-break between the "&struct" and "foo" part would break it. But a quick test shows that " * &struct \n * foo\n" works pefectly well with current kernel-doc. So time to mass-apply these changes! Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: David Herrmann <dh.herrmann@gmail.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1483044517-5770-4-git-send-email-daniel.vetter@ffwll.ch
2016-12-13dma-buf: Update cpu access documentationDaniel Vetter1-8/+83
- Again move the information relevant for driver writers next to the callbacks. - Put the overview and userspace interface documentation into a DOC: section within the code. - Remove the text that mmap needs to be coherent - since the DMA_BUF_IOCTL_SYNC landed that's no longer the case. But keep the text that for pte zapping exporters need to adjust the address space. - Add a FIXME that kmap and the new begin/end stuff used by the SYNC ioctl don't really mix correctly. That's something I just realized while doing this doc rework. - Augment function and structure docs like usual. Cc: linux-doc@vger.kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: Sumit Semwal <sumit.semwal@linaro.org> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org> [sumits: fix cosmetic issues] Link: http://patchwork.freedesktop.org/patch/msgid/20161209185309.1682-5-daniel.vetter@ffwll.ch
2016-12-13dma-buf: Reorganize device dma access docsDaniel Vetter1-23/+110
- Put the initial overview for dma-buf into dma-buf.rst. - Put all the comments about detailed semantics into the right kernel-doc comment for functions or ops structure member. - To allow that detail, switch the reworked kerneldoc to inline style for dma_buf_ops. - Tie everything together into a much more streamlined overview comment, relying on the hyperlinks for all the details. - Also sprinkle some links into the kerneldoc for dma_buf and dma_buf_attachment to tie it all together. Cc: linux-doc@vger.kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: Sumit Semwal <sumit.semwal@linaro.org> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org> Link: http://patchwork.freedesktop.org/patch/msgid/20161209185309.1682-4-daniel.vetter@ffwll.ch
2016-10-25dma-buf: Rename struct fence to dma_fenceChris Wilson1-2/+2
I plan to usurp the short name of struct fence for a core kernel struct, and so I need to rename the specialised fence/timeline for DMA operations to make room. A consensus was reached in https://lists.freedesktop.org/archives/dri-devel/2016-July/113083.html that making clear this fence applies to DMA operations was a good thing. Since then the patch has grown a bit as usage increases, so hopefully it remains a good thing! (v2...: rebase, rerun spatch) v3: Compile on msm, spotted a manual fixup that I broke. v4: Try again for msm, sorry Daniel coccinelle script: @@ @@ - struct fence + struct dma_fence @@ @@ - struct fence_ops + struct dma_fence_ops @@ @@ - struct fence_cb + struct dma_fence_cb @@ @@ - struct fence_array + struct dma_fence_array @@ @@ - enum fence_flag_bits + enum dma_fence_flag_bits @@ @@ ( - fence_init + dma_fence_init | - fence_release + dma_fence_release | - fence_free + dma_fence_free | - fence_get + dma_fence_get | - fence_get_rcu + dma_fence_get_rcu | - fence_put + dma_fence_put | - fence_signal + dma_fence_signal | - fence_signal_locked + dma_fence_signal_locked | - fence_default_wait + dma_fence_default_wait | - fence_add_callback + dma_fence_add_callback | - fence_remove_callback + dma_fence_remove_callback | - fence_enable_sw_signaling + dma_fence_enable_sw_signaling | - fence_is_signaled_locked + dma_fence_is_signaled_locked | - fence_is_signaled + dma_fence_is_signaled | - fence_is_later + dma_fence_is_later | - fence_later + dma_fence_later | - fence_wait_timeout + dma_fence_wait_timeout | - fence_wait_any_timeout + dma_fence_wait_any_timeout | - fence_wait + dma_fence_wait | - fence_context_alloc + dma_fence_context_alloc | - fence_array_create + dma_fence_array_create | - to_fence_array + to_dma_fence_array | - fence_is_array + dma_fence_is_array | - trace_fence_emit + trace_dma_fence_emit | - FENCE_TRACE + DMA_FENCE_TRACE | - FENCE_WARN + DMA_FENCE_WARN | - FENCE_ERR + DMA_FENCE_ERR ) ( ... ) Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk> Acked-by: Sumit Semwal <sumit.semwal@linaro.org> Acked-by: Christian König <christian.koenig@amd.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/20161025120045.28839-1-chris@chris-wilson.co.uk
2016-06-20dma-buf: remove dma_buf_debugfs_create_file()Mathias Krause1-2/+0
There is only a single user of dma_buf_debugfs_create_file() and that one got the function pointer cast wrong. With that one fixed, there is no need to have a wrapper for debugfs_create_file(), just call it directly. With no users left, we can remove dma_buf_debugfs_create_file(). While at it, simplify the error handling in dma_buf_init_debugfs() slightly. Signed-off-by: Mathias Krause <minipli@googlemail.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org> Link: http://patchwork.freedesktop.org/patch/msgid/1466339491-12639-2-git-send-email-minipli@googlemail.com
2016-05-31dma-buf: headerdoc fixesRob Clark1-3/+10
Apparently nobody noticed that dma-buf.h wasn't actually pulled into docbook build. And as a result the headerdoc comments bitrot a bit. Add missing params/fields. Signed-off-by: Rob Clark <robdclark@gmail.com> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
2016-03-19dma-buf, drm, ion: Propagate error code from dma_buf_start_cpu_access()Chris Wilson1-3/+3
Drivers, especially i915.ko, can fail during the initial migration of a dma-buf for CPU access. However, the error code from the driver was not being propagated back to ioctl and so userspace was blissfully ignorant of the failure. Rendering corruption ensues. Whilst fixing the ioctl to return the error code from dma_buf_start_cpu_access(), also do the same for dma_buf_end_cpu_access(). For most drivers, dma_buf_end_cpu_access() cannot fail. i915.ko however, as most drivers would, wants to avoid being uninterruptible (as would be required to guarrantee no failure when flushing the buffer to the device). As userspace already has to handle errors from the SYNC_IOCTL, take advantage of this to be able to restart the syscall across signals. This fixes a coherency issue for i915.ko as well as reducing the uninterruptible hold upon its BKL, the struct_mutex. Fixes commit c11e391da2a8fe973c3c2398452000bed505851e Author: Daniel Vetter <daniel.vetter@ffwll.ch> Date: Thu Feb 11 20:04:51 2016 -0200 dma-buf: Add ioctls to allow userspace to flush Testcase: igt/gem_concurrent_blit/*dmabuf*interruptible Testcase: igt/prime_mmap_coherency/ioctl-errors Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tiago Vignatti <tiago.vignatti@intel.com> Cc: Stéphane Marchesin <marcheu@chromium.org> Cc: David Herrmann <dh.herrmann@gmail.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Daniel Vetter <daniel.vetter@intel.com> CC: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Cc: intel-gfx@lists.freedesktop.org Cc: devel@driverdev.osuosl.org Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/1458331359-2634-1-git-send-email-chris@chris-wilson.co.uk
2016-02-09dma-buf: Remove range-based flushTiago Vignatti1-7/+5
This patch removes range-based information used for optimizations in begin_cpu_access and end_cpu_access. We don't have any user nor implementation using range-based flush. It seems a consensus that if we ever want something like that again (or even more robust using 2D, 3D sub-range regions) we can use the upcoming dma-buf sync ioctl for such. Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Daniel Vetter <daniel.vetter@intel.com> Signed-off-by: Tiago Vignatti <tiago.vignatti@intel.com> Reviewed-by: Stéphane Marchesin <marcheu@chromium.org> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/1450820214-12509-3-git-send-email-tiago.vignatti@intel.com
2015-05-13dma-buf: add ref counting for module as exporterSumit Semwal1-2/+8
Add reference counting on a kernel module that exports dma-buf and implements its operations. This prevents the module from being unloaded while DMABUF file is in use. The original patch [1] was submitted by Tomasz Stanislawski, but this is a simpler way to do it. v3: call module_put() as late as possible, per gregkh's comment. v2: move owner to struct dma_buf, and use DEFINE_DMA_BUF_EXPORT_INFO macro to simplify the change. Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org> [1]: https://lkml.org/lkml/2012/8/8/163
2015-04-21dma-buf: cleanup dma_buf_export() to make it easily extensibleSumit Semwal1-6/+28
At present, dma_buf_export() takes a series of parameters, which makes it difficult to add any new parameters for exporters, if required. Make it simpler by moving all these parameters into a struct, and pass the struct * as parameter to dma_buf_export(). While at it, unite dma_buf_export_named() with dma_buf_export(), and change all callers accordingly. Reviewed-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Acked-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com> Acked-by: Dave Airlie <airlied@redhat.com> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
2014-07-08dma-buf: add poll support, v3Maarten Lankhorst1-0/+12
Thanks to Fengguang Wu for spotting a missing static cast. v2: - Kill unused variable need_shared. v3: - Clarify the BUG() in dma_buf_release some more. (Rob Clark) Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> Acked-by: Sumit Semwal <sumit.semwal@linaro.org> Acked-by: Daniel Vetter <daniel@ffwll.ch> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-08dma-buf: use reservation objectsMaarten Lankhorst1-3/+6
This allows reservation objects to be used in dma-buf. it's required for implementing polling support on the fences that belong to a dma-buf. Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> Acked-by: Mauro Carvalho Chehab <m.chehab@samsung.com> #drivers/media/v4l2-core/ Acked-by: Thomas Hellstrom <thellstrom@vmware.com> #drivers/gpu/drm/ttm Acked-by: Sumit Semwal <sumit.semwal@linaro.org> Acked-by: Daniel Vetter <daniel@ffwll.ch> Signed-off-by: Vincent Stehlé <vincent.stehle@laposte.net> #drivers/gpu/drm/armada/ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-02-13dma-buf: update debugfs outputSumit Semwal1-1/+1
Russell King observed 'wierd' looking output from debugfs, and also suggested better ways of getting device names (use KBUILD_MODNAME, dev_name()) This patch addresses these issues to make the debugfs output correct and better looking. While at it, replace seq_printf with seq_puts to remove the checkpatch.pl warnings. Reported-by: Russell King - ARM Linux <linux@arm.linux.org.uk> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
2013-05-01dma-buf: Add debugfs supportSumit Semwal1-1/+4
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>
2013-05-01dma-buf: replace dma_buf_export() with dma_buf_export_named()Sumit Semwal1-2/+9
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>
2013-02-27dma-buf: implement vmap refcounting in the interface logicDaniel Vetter1-1/+3
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>
2013-01-29Merge branch 'master' into for-nextJiri Kosina1-99/+0
Conflicts: drivers/devfreq/exynos4_bus.c Sync with Linus' tree to be able to apply patches that are against newer code (mvneta).
2013-01-09treewide: Fix typo in various driversMasanari Iida1-1/+1
Correct spelling typo in printk within various drivers. Signed-off-by: Masanari Iida <standby24x7@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2012-12-20dma-buf: remove fallback for !CONFIG_DMA_SHARED_BUFFERMaarten Lankhorst1-99/+0
Documentation says that code requiring dma-buf should add it to select, so inline fallbacks are not going to be used. A link error will make it obvious what went wrong, instead of silently doing nothing at runtime. Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Rob Clark <rob.clark@linaro.org> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
2012-05-25dma-buf: minor documentation fixes.Sumit Semwal1-0/+3
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>
2012-05-25dma-buf: add vmap interfaceDave Airlie1-0/+14
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>
2012-05-25dma-buf: mmap supportDaniel Vetter1-0/+16
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>
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