linux-dev/drivers/dma-buf/Kconfig, branch master

dma-buf: deprecate DMABUF_SYSFS_STATS

2022-06-23T08:51:43Z

Add a warning that this UAPI wasn't such a good idea and shouldn't be used by anybody. That should give us a better chance to remove it at some point and prevents others from running into the same issues. Signed-off-by: Christian König Reviewed-by: T.J. Mercier Link: https://patchwork.freedesktop.org/patch/msgid/20220617085702.4298-1-christian.koenig@amd.com

dma-buf: DMABUF_SYSFS_STATS should depend on DMA_SHARED_BUFFER

2021-09-07T07:12:21Z

DMA-BUF sysfs statistics are an option of DMA-BUF. It does not make much sense to bother the user with a question about DMA-BUF sysfs statistics if DMA-BUF itself is not enabled. Worse, enabling the statistics enables the feature. Fixes: bdb8d06dfefd666d ("dmabuf: Add the capability to expose DMA-BUF stats in sysfs") Signed-off-by: Geert Uytterhoeven Signed-off-by: Sumit Semwal Link: https://patchwork.freedesktop.org/patch/msgid/20210902124913.2698760-4-geert@linux-m68k.org

dma-buf: DMABUF_DEBUG should depend on DMA_SHARED_BUFFER

2021-09-07T07:12:21Z

DMA-BUF debug checks are an option of DMA-BUF. Enabling DMABUF_DEBUG without DMA_SHARED_BUFFER does not have any impact, as drivers/dma-buf/ is not entered during the build when DMA_SHARED_BUFFER is disabled. Fixes: 84335675f2223cbd ("dma-buf: Add debug option") Signed-off-by: Geert Uytterhoeven Signed-off-by: Sumit Semwal Link: https://patchwork.freedesktop.org/patch/msgid/20210902124913.2698760-3-geert@linux-m68k.org

dma-buf: DMABUF_MOVE_NOTIFY should depend on DMA_SHARED_BUFFER

2021-09-02T14:49:11Z

Move notify between drivers is an option of DMA-BUF. Enabling DMABUF_MOVE_NOTIFY without DMA_SHARED_BUFFER does not have any impact, as drivers/dma-buf/ is not entered during the build when DMA_SHARED_BUFFER is disabled. Fixes: bb42df4662a44765 ("dma-buf: add dynamic DMA-buf handling v15") Signed-off-by: Geert Uytterhoeven Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20210902124913.2698760-2-geert@linux-m68k.org

dmabuf: Add the capability to expose DMA-BUF stats in sysfs

2021-06-15T09:50:24Z

Overview ======== The patch adds DMA-BUF statistics to /sys/kernel/dmabuf/buffers. It allows statistics to be enabled for each DMA-BUF in sysfs by enabling the config CONFIG_DMABUF_SYSFS_STATS. The following stats will be exposed by the interface: /sys/kernel/dmabuf/buffers//exporter_name /sys/kernel/dmabuf/buffers//size /sys/kernel/dmabuf/buffers//attachments//device /sys/kernel/dmabuf/buffers//attachments//map_counter The inode_number is unique for each DMA-BUF and was added earlier [1] in order to allow userspace to track DMA-BUF usage across different processes. Use Cases ========= The interface provides a way to gather DMA-BUF per-buffer statistics from production devices. These statistics will be used to derive DMA-BUF per-exporter stats and per-device usage stats for Android Bug reports. The corresponding userspace changes can be found at [2]. Telemetry tools will also capture this information(along with other memory metrics) periodically as well as on important events like a foreground app kill (which might have been triggered by Low Memory Killer). It will also contribute to provide a snapshot of the system memory usage on other events such as OOM kills and Application Not Responding events. Background ========== Currently, there are two existing interfaces that provide information about DMA-BUFs. 1) /sys/kernel/debug/dma_buf/bufinfo debugfs is however unsuitable to be mounted in production systems and cannot be considered as an alternative to the sysfs interface being proposed. 2) proc//fdinfo/ The proc//fdinfo/ files expose information about DMA-BUF fds. However, the existing procfs interfaces can only provide information about the buffers for which processes hold fds or have the buffers mmapped into their address space. Since the procfs interfaces alone cannot provide a full picture of all DMA-BUFs in the system, there is the need for an alternate interface to provide this information on production systems. The patch contains the following major improvements over v1: 1) Each attachment is represented by its own directory to allow creating a symlink to the importing device and to also provide room for future expansion. 2) The number of distinct mappings of each attachment is exposed in a separate file. 3) The per-buffer statistics are now in /sys/kernel/dmabuf/buffers inorder to make the interface expandable in future. All of the improvements above are based on suggestions/feedback from Daniel Vetter and Christian König. A shell script that can be run on a classic Linux environment to read out the DMA-BUF statistics can be found at [3](suggested by John Stultz). [1]: https://lore.kernel.org/patchwork/patch/1088791/ [2]: https://android-review.googlesource.com/q/topic:%22dmabuf-sysfs%22+(status:open%20OR%20status:merged) [3]: https://android-review.googlesource.com/c/platform/system/memory/libmeminfo/+/1549734 Reviewed-by: Greg Kroah-Hartman Signed-off-by: Hridya Valsaraju Reported-by: kernel test robot Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20210603214758.2955251-1-hridya@google.com

dma-buf: Add debug option

2021-01-18T13:26:51Z

We have too many people abusing the struct page they can get at but really shouldn't in importers. Aside from that the backing page might simply not exist (for dynamic p2p mappings) looking at it and using it e.g. for mmap can also wreak the page handling of the exporter completely. Importers really must go through the proper interface like dma_buf_mmap for everything. I'm semi-tempted to enforce this for dynamic importers since those really have no excuse at all to break the rules. Unfortuantely we can't store the right pointers somewhere safe to make sure we oops on something recognizable, so best is to just wrangle them a bit by flipping all the bits. At least on x86 kernel addresses have all their high bits sets and the struct page array is fairly low in the kernel mapping, so flipping all the bits gives us a very high pointer in userspace and hence excellent chances for an invalid dereference. v2: Add a note to the @map_dma_buf hook that exporters shouldn't do fancy caching tricks, which would blow up with this address scrambling trick here (Chris) Enable by default when CONFIG_DMA_API_DEBUG is enabled. v3: Only one copy of the mangle/unmangle code (Christian) v4: #ifdef, not #if (0day) v5: sg_table can also be an ERR_PTR (Chris, Christian) Reviewed-by: Chris Wilson Reviewed-by: Christian König Signed-off-by: Daniel Vetter Cc: Chris Wilson Cc: Sumit Semwal Cc: "Christian König" Cc: David Stevens Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20210115164739.3958206-1-daniel.vetter@ffwll.ch

treewide: replace '---help---' in Kconfig files with 'help'

2020-06-13T16:57:21Z

Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over '---help---'"), the number of '---help---' has been gradually decreasing, but there are still more than 2400 instances. This commit finishes the conversion. While I touched the lines, I also fixed the indentation. There are a variety of indentation styles found. a) 4 spaces + '---help---' b) 7 spaces + '---help---' c) 8 spaces + '---help---' d) 1 space + 1 tab + '---help---' e) 1 tab + '---help---' (correct indentation) f) 1 tab + 1 space + '---help---' g) 1 tab + 2 spaces + '---help---' In order to convert all of them to 1 tab + 'help', I ran the following commend: $ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/' Signed-off-by: Masahiro Yamada

dma-buf: Improve CONFIG_DMABUF_MOVE_NOTIFY help text

2020-03-25T18:36:46Z

Improve the help text for the CONFIG_DMABUF_MOVE_NOTIFY symbol by: 1. Removing duplicated single quotes, 2. Adding a missing subject, 3. Fixing a misspelling of "yet", 4. Wrapping long lines. Fixes: bb42df4662a44765 ("dma-buf: add dynamic DMA-buf handling v15") Reviewed-by: Christian König Signed-off-by: Geert Uytterhoeven Signed-off-by: Alex Deucher Link: https://patchwork.freedesktop.org/patch/msgid/20200324125442.21983-1-geert+renesas@glider.be

dma-buf: add dynamic DMA-buf handling v15

2020-02-27T13:58:00Z

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 Reviewed-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/353993/?series=73646&rev=1

dma-buf: Fix a typo in Kconfig

2020-02-17T09:27:25Z

A 'h' ismissing in' syncronization' Signed-off-by: Christophe JAILLET Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20200216114708.20583-1-christophe.jaillet@wanadoo.fr