If the scheduler rt thread gets stuck on a mutex that we're holding
while waiting for gpu workloads to complete, we have a problem.
Add dma-fence annotations so that lockdep can check this for us.
I've tried to quite carefully review this, and I think it's at the
right spot. But obviosly no expert on drm scheduler.
Cc: linux-media(a)vger.kernel.org
Cc: linaro-mm-sig(a)lists.linaro.org
Cc: linux-rdma(a)vger.kernel.org
Cc: amd-gfx(a)lists.freedesktop.org
Cc: intel-gfx(a)lists.freedesktop.org
Cc: Chris Wilson <chris(a)chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst(a)linux.intel.com>
Cc: Christian König <christian.koenig(a)amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter(a)intel.com>
---
drivers/gpu/drm/scheduler/sched_main.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 9a0d77a68018..f69abc4e70d3 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -764,9 +764,12 @@ static int drm_sched_main(void *param)
{
struct drm_gpu_scheduler *sched = (struct drm_gpu_scheduler *)param;
int r;
+ bool fence_cookie;
sched_set_fifo_low(current);
+ fence_cookie = dma_fence_begin_signalling();
+
while (!kthread_should_stop()) {
struct drm_sched_entity *entity = NULL;
struct drm_sched_fence *s_fence;
@@ -824,6 +827,9 @@ static int drm_sched_main(void *param)
wake_up(&sched->job_scheduled);
}
+
+ dma_fence_end_signalling(fence_cookie);
+
return 0;
}
--
2.28.0
This is rather overkill since currently all drivers call this from
hardirq (or at least timers). But maybe in the future we're going to
have thread irq handlers and what not, doesn't hurt to be prepared.
Plus this is an easy start for sprinkling these fence annotations into
shared code.
Cc: linux-media(a)vger.kernel.org
Cc: linaro-mm-sig(a)lists.linaro.org
Cc: linux-rdma(a)vger.kernel.org
Cc: amd-gfx(a)lists.freedesktop.org
Cc: intel-gfx(a)lists.freedesktop.org
Cc: Chris Wilson <chris(a)chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst(a)linux.intel.com>
Cc: Christian König <christian.koenig(a)amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter(a)intel.com>
---
drivers/gpu/drm/drm_vblank.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
index f135b79593dd..ba7e741764aa 100644
--- a/drivers/gpu/drm/drm_vblank.c
+++ b/drivers/gpu/drm/drm_vblank.c
@@ -24,6 +24,7 @@
* OTHER DEALINGS IN THE SOFTWARE.
*/
+#include <linux/dma-fence.h>
#include <linux/export.h>
#include <linux/kthread.h>
#include <linux/moduleparam.h>
@@ -1913,7 +1914,7 @@ bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe)
{
struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
unsigned long irqflags;
- bool disable_irq;
+ bool disable_irq, fence_cookie;
if (drm_WARN_ON_ONCE(dev, !drm_dev_has_vblank(dev)))
return false;
@@ -1921,6 +1922,8 @@ bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe)
if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
return false;
+ fence_cookie = dma_fence_begin_signalling();
+
spin_lock_irqsave(&dev->event_lock, irqflags);
/* Need timestamp lock to prevent concurrent execution with
@@ -1933,6 +1936,7 @@ bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe)
if (!vblank->enabled) {
spin_unlock(&dev->vblank_time_lock);
spin_unlock_irqrestore(&dev->event_lock, irqflags);
+ dma_fence_end_signalling(fence_cookie);
return false;
}
@@ -1959,6 +1963,8 @@ bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe)
if (disable_irq)
vblank_disable_fn(&vblank->disable_timer);
+ dma_fence_end_signalling(fence_cookie);
+
return true;
}
EXPORT_SYMBOL(drm_handle_vblank);
--
2.28.0
This is a bit disappointing since we need to split the annotations
over all the different parts.
I was considering just leaking the critical section into the
->atomic_commit_tail callback of each driver. But that would mean we
need to pass the fence_cookie into each driver (there's a total of 13
implementations of this hook right now), so bad flag day. And also a
bit leaky abstraction.
Hence just do it function-by-function.
Cc: linux-media(a)vger.kernel.org
Cc: linaro-mm-sig(a)lists.linaro.org
Cc: linux-rdma(a)vger.kernel.org
Cc: amd-gfx(a)lists.freedesktop.org
Cc: intel-gfx(a)lists.freedesktop.org
Cc: Chris Wilson <chris(a)chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst(a)linux.intel.com>
Cc: Christian König <christian.koenig(a)amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter(a)intel.com>
---
drivers/gpu/drm/drm_atomic_helper.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 549a31e6042c..23013209d4bf 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1567,6 +1567,7 @@ EXPORT_SYMBOL(drm_atomic_helper_wait_for_flip_done);
void drm_atomic_helper_commit_tail(struct drm_atomic_state *old_state)
{
struct drm_device *dev = old_state->dev;
+ bool fence_cookie = dma_fence_begin_signalling();
drm_atomic_helper_commit_modeset_disables(dev, old_state);
@@ -1578,6 +1579,8 @@ void drm_atomic_helper_commit_tail(struct drm_atomic_state *old_state)
drm_atomic_helper_commit_hw_done(old_state);
+ dma_fence_end_signalling(fence_cookie);
+
drm_atomic_helper_wait_for_vblanks(dev, old_state);
drm_atomic_helper_cleanup_planes(dev, old_state);
@@ -1597,6 +1600,7 @@ EXPORT_SYMBOL(drm_atomic_helper_commit_tail);
void drm_atomic_helper_commit_tail_rpm(struct drm_atomic_state *old_state)
{
struct drm_device *dev = old_state->dev;
+ bool fence_cookie = dma_fence_begin_signalling();
drm_atomic_helper_commit_modeset_disables(dev, old_state);
@@ -1609,6 +1613,8 @@ void drm_atomic_helper_commit_tail_rpm(struct drm_atomic_state *old_state)
drm_atomic_helper_commit_hw_done(old_state);
+ dma_fence_end_signalling(fence_cookie);
+
drm_atomic_helper_wait_for_vblanks(dev, old_state);
drm_atomic_helper_cleanup_planes(dev, old_state);
@@ -1624,6 +1630,9 @@ static void commit_tail(struct drm_atomic_state *old_state)
ktime_t start;
s64 commit_time_ms;
unsigned int i, new_self_refresh_mask = 0;
+ bool fence_cookie;
+
+ fence_cookie = dma_fence_begin_signalling();
funcs = dev->mode_config.helper_private;
@@ -1652,6 +1661,8 @@ static void commit_tail(struct drm_atomic_state *old_state)
if (new_crtc_state->self_refresh_active)
new_self_refresh_mask |= BIT(i);
+ dma_fence_end_signalling(fence_cookie);
+
if (funcs && funcs->atomic_commit_tail)
funcs->atomic_commit_tail(old_state);
else
@@ -1810,6 +1821,7 @@ int drm_atomic_helper_commit(struct drm_device *dev,
bool nonblock)
{
int ret;
+ bool fence_cookie;
if (state->async_update) {
ret = drm_atomic_helper_prepare_planes(dev, state);
@@ -1832,6 +1844,8 @@ int drm_atomic_helper_commit(struct drm_device *dev,
if (ret)
return ret;
+ fence_cookie = dma_fence_begin_signalling();
+
if (!nonblock) {
ret = drm_atomic_helper_wait_for_fences(dev, state, true);
if (ret)
@@ -1869,6 +1883,7 @@ int drm_atomic_helper_commit(struct drm_device *dev,
*/
drm_atomic_state_get(state);
+ dma_fence_end_signalling(fence_cookie);
if (nonblock)
queue_work(system_unbound_wq, &state->commit_work);
else
@@ -1877,6 +1892,7 @@ int drm_atomic_helper_commit(struct drm_device *dev,
return 0;
err:
+ dma_fence_end_signalling(fence_cookie);
drm_atomic_helper_cleanup_planes(dev, state);
return ret;
}
--
2.28.0
From: Rob Clark <robdclark(a)chromium.org>
This doesn't remove *all* the struct_mutex, but it covers the worst
of it, ie. shrinker/madvise/free/retire. The submit path still uses
struct_mutex, but it still needs *something* serialize a portion of
the submit path, and lock_stat mostly just shows the lock contention
there being with other submits. And there are a few other bits of
struct_mutex usage in less critical paths (debugfs, etc). But this
seems like a reasonable step in the right direction.
v2: teach lockdep about shrinker locking patters (danvet) and
convert to obj->resv locking (danvet)
v3: fix get_vaddr locking for legacy userspace (relocs), devcoredump,
and rd/hangrd
Rob Clark (23):
drm/msm: Fix a couple incorrect usages of get_vaddr_active()
drm/msm/gem: Add obj->lock wrappers
drm/msm/gem: Rename internal get_iova_locked helper
drm/msm/gem: Move prototypes to msm_gem.h
drm/msm/gem: Add some _locked() helpers
drm/msm/gem: Move locking in shrinker path
drm/msm/submit: Move copy_from_user ahead of locking bos
drm/msm: Do rpm get sooner in the submit path
drm/msm/gem: Switch over to obj->resv for locking
drm/msm: Use correct drm_gem_object_put() in fail case
drm/msm: Drop chatty trace
drm/msm: Move update_fences()
drm/msm: Add priv->mm_lock to protect active/inactive lists
drm/msm: Document and rename preempt_lock
drm/msm: Protect ring->submits with it's own lock
drm/msm: Refcount submits
drm/msm: Remove obj->gpu
drm/msm: Drop struct_mutex from the retire path
drm/msm: Drop struct_mutex in free_object() path
drm/msm: Remove msm_gem_free_work
drm/msm: Drop struct_mutex in madvise path
drm/msm: Drop struct_mutex in shrinker path
drm/msm: Don't implicit-sync if only a single ring
drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 6 +-
drivers/gpu/drm/msm/adreno/a5xx_preempt.c | 12 +-
drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 6 +-
drivers/gpu/drm/msm/disp/mdp4/mdp4_crtc.c | 1 +
drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c | 1 +
drivers/gpu/drm/msm/dsi/dsi_host.c | 1 +
drivers/gpu/drm/msm/msm_debugfs.c | 7 +
drivers/gpu/drm/msm/msm_drv.c | 21 +-
drivers/gpu/drm/msm/msm_drv.h | 73 +-----
drivers/gpu/drm/msm/msm_fbdev.c | 1 +
drivers/gpu/drm/msm/msm_gem.c | 266 +++++++++++-----------
drivers/gpu/drm/msm/msm_gem.h | 133 +++++++++--
drivers/gpu/drm/msm/msm_gem_shrinker.c | 81 ++-----
drivers/gpu/drm/msm/msm_gem_submit.c | 158 ++++++++-----
drivers/gpu/drm/msm/msm_gpu.c | 110 +++++----
drivers/gpu/drm/msm/msm_gpu.h | 5 +-
drivers/gpu/drm/msm/msm_rd.c | 2 +-
drivers/gpu/drm/msm/msm_ringbuffer.c | 3 +-
drivers/gpu/drm/msm/msm_ringbuffer.h | 13 +-
19 files changed, 495 insertions(+), 405 deletions(-)
--
2.26.2
On Thu, Aug 27, 2020 at 09:31:27AM -0400, Laura Abbott wrote:
> On 8/27/20 8:36 AM, Greg Kroah-Hartman wrote:
> > The ION android code has long been marked to be removed, now that we
> > dma-buf support merged into the real part of the kernel.
> >
> > It was thought that we could wait to remove the ion kernel at a later
> > time, but as the out-of-tree Android fork of the ion code has diverged
> > quite a bit, and any Android device using the ion interface uses that
> > forked version and not this in-tree version, the in-tree copy of the
> > code is abandonded and not used by anyone.
> >
> > Combine this abandoned codebase with the need to make changes to it in
> > order to keep the kernel building properly, which then causes merge
> > issues when merging those changes into the out-of-tree Android code, and
> > you end up with two different groups of people (the in-kernel-tree
> > developers, and the Android kernel developers) who are both annoyed at
> > the current situation. Because of this problem, just drop the in-kernel
> > copy of the ion code now, as it's not used, and is only causing problems
> > for everyone involved.
> >
> > Cc: "Arve Hjønnevåg" <arve(a)android.com>
> > Cc: "Christian König" <christian.koenig(a)amd.com>
> > Cc: Christian Brauner <christian(a)brauner.io>
> > Cc: Christoph Hellwig <hch(a)infradead.org>
> > Cc: Hridya Valsaraju <hridya(a)google.com>
> > Cc: Joel Fernandes <joel(a)joelfernandes.org>
> > Cc: John Stultz <john.stultz(a)linaro.org>
> > Cc: Laura Abbott <laura(a)labbott.name>
> > Cc: Martijn Coenen <maco(a)android.com>
> > Cc: Shuah Khan <shuah(a)kernel.org>
> > Cc: Sumit Semwal <sumit.semwal(a)linaro.org>
> > Cc: Suren Baghdasaryan <surenb(a)google.com>
> > Cc: Todd Kjos <tkjos(a)android.com>
> > Cc: devel(a)driverdev.osuosl.org
> > Cc: dri-devel(a)lists.freedesktop.org
> > Cc: linaro-mm-sig(a)lists.linaro.org
> > Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
>
> We discussed this at the Android MC on Monday and the plan was to
> remove it after the next LTS release.
As 5.10 will be the next LTS release, I have now merged it to my
"testing" branch to go into 5.11-rc1.
thanks,
greg k-h
On Wed, Oct 14, 2020 at 09:16:01AM -0700, Jianxin Xiong wrote:
> 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(a)intel.com>
lgtm, thanks for creating this and giving it a spin.
I'll queue this up in drm-misc-next for 5.11, should show up in linux-next
after the merge window is closed.
Cheers, Daniel
> ---
> drivers/dma-buf/dma-buf.c | 21 +++++++++++++++++++++
> include/linux/dma-buf.h | 3 ++-
> 2 files changed, 23 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
> index 844967f..7309c83 100644
> --- a/drivers/dma-buf/dma-buf.c
> +++ b/drivers/dma-buf/dma-buf.c
> @@ -851,6 +851,9 @@ void dma_buf_unpin(struct dma_buf_attachment *attach)
> * Returns sg_table containing the scatterlist to be returned; returns ERR_PTR
> * on error. May return -EINTR if it is interrupted by a signal.
> *
> + * On success, the DMA addresses and lengths in the returned scatterlist are
> + * PAGE_SIZE aligned.
> + *
> * A mapping must be unmapped by using dma_buf_unmap_attachment(). Note that
> * the underlying backing storage is pinned for as long as a mapping exists,
> * therefore users/importers should not hold onto a mapping for undue amounts of
> @@ -904,6 +907,24 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
> attach->dir = direction;
> }
>
> +#ifdef CONFIG_DMA_API_DEBUG
> + {
> + struct scatterlist *sg;
> + u64 addr;
> + int len;
> + int i;
> +
> + for_each_sgtable_dma_sg(sg_table, sg, i) {
> + addr = sg_dma_address(sg);
> + len = sg_dma_len(sg);
> + if (!PAGE_ALIGNED(addr) || !PAGE_ALIGNED(len)) {
> + pr_debug("%s: addr %llx or len %x is not page aligned!\n",
> + __func__, addr, len);
> + }
> + }
> + }
> +#endif /* CONFIG_DMA_API_DEBUG */
> +
> return sg_table;
> }
> EXPORT_SYMBOL_GPL(dma_buf_map_attachment);
> diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
> index a2ca294e..4a5fa70 100644
> --- a/include/linux/dma-buf.h
> +++ b/include/linux/dma-buf.h
> @@ -145,7 +145,8 @@ struct dma_buf_ops {
> *
> * A &sg_table scatter list of or the backing storage of the DMA buffer,
> * already mapped into the device address space of the &device attached
> - * with the provided &dma_buf_attachment.
> + * with the provided &dma_buf_attachment. The addresses and lengths in
> + * the scatter list are PAGE_SIZE aligned.
> *
> * On failure, returns a negative error value wrapped into a pointer.
> * May also return -EINTR when a signal was received while being
> --
> 1.8.3.1
>
> _______________________________________________
> dri-devel mailing list
> dri-devel(a)lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
From: Rob Clark <robdclark(a)chromium.org>
This doesn't remove *all* the struct_mutex, but it covers the worst
of it, ie. shrinker/madvise/free/retire. The submit path still uses
struct_mutex, but it still needs *something* serialize a portion of
the submit path, and lock_stat mostly just shows the lock contention
there being with other submits. And there are a few other bits of
struct_mutex usage in less critical paths (debugfs, etc). But this
seems like a reasonable step in the right direction.
v2: teach lockdep about shrinker locking patters (danvet) and
convert to obj->resv locking (danvet)
Rob Clark (22):
drm/msm/gem: Add obj->lock wrappers
drm/msm/gem: Rename internal get_iova_locked helper
drm/msm/gem: Move prototypes to msm_gem.h
drm/msm/gem: Add some _locked() helpers
drm/msm/gem: Move locking in shrinker path
drm/msm/submit: Move copy_from_user ahead of locking bos
drm/msm: Do rpm get sooner in the submit path
drm/msm/gem: Switch over to obj->resv for locking
drm/msm: Use correct drm_gem_object_put() in fail case
drm/msm: Drop chatty trace
drm/msm: Move update_fences()
drm/msm: Add priv->mm_lock to protect active/inactive lists
drm/msm: Document and rename preempt_lock
drm/msm: Protect ring->submits with it's own lock
drm/msm: Refcount submits
drm/msm: Remove obj->gpu
drm/msm: Drop struct_mutex from the retire path
drm/msm: Drop struct_mutex in free_object() path
drm/msm: remove msm_gem_free_work
drm/msm: drop struct_mutex in madvise path
drm/msm: Drop struct_mutex in shrinker path
drm/msm: Don't implicit-sync if only a single ring
drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 4 +-
drivers/gpu/drm/msm/adreno/a5xx_preempt.c | 12 +-
drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 4 +-
drivers/gpu/drm/msm/disp/mdp4/mdp4_crtc.c | 1 +
drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c | 1 +
drivers/gpu/drm/msm/dsi/dsi_host.c | 1 +
drivers/gpu/drm/msm/msm_debugfs.c | 7 +
drivers/gpu/drm/msm/msm_drv.c | 21 +-
drivers/gpu/drm/msm/msm_drv.h | 73 ++-----
drivers/gpu/drm/msm/msm_fbdev.c | 1 +
drivers/gpu/drm/msm/msm_gem.c | 245 ++++++++++------------
drivers/gpu/drm/msm/msm_gem.h | 131 ++++++++++--
drivers/gpu/drm/msm/msm_gem_shrinker.c | 81 +++----
drivers/gpu/drm/msm/msm_gem_submit.c | 154 +++++++++-----
drivers/gpu/drm/msm/msm_gpu.c | 98 +++++----
drivers/gpu/drm/msm/msm_gpu.h | 5 +-
drivers/gpu/drm/msm/msm_ringbuffer.c | 3 +-
drivers/gpu/drm/msm/msm_ringbuffer.h | 13 +-
18 files changed, 459 insertions(+), 396 deletions(-)
--
2.26.2
Am 08.10.20 um 23:49 schrieb John Hubbard:
> On 10/8/20 4:23 AM, Christian König wrote:
>> Add the new vma_set_file() function to allow changing
>> vma->vm_file with the necessary refcount dance.
>>
>> v2: add more users of this.
>>
>> Signed-off-by: Christian König <christian.koenig(a)amd.com>
>> ---
>> drivers/dma-buf/dma-buf.c | 16 +++++-----------
>> drivers/gpu/drm/etnaviv/etnaviv_gem.c | 4 +---
>> drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 3 +--
>> drivers/gpu/drm/i915/gem/i915_gem_mman.c | 4 ++--
>> drivers/gpu/drm/msm/msm_gem.c | 4 +---
>> drivers/gpu/drm/omapdrm/omap_gem.c | 3 +--
>> drivers/gpu/drm/vgem/vgem_drv.c | 3 +--
>> drivers/staging/android/ashmem.c | 5 ++---
>> include/linux/mm.h | 2 ++
>> mm/mmap.c | 16 ++++++++++++++++
>> 10 files changed, 32 insertions(+), 28 deletions(-)
>
> Looks like a nice cleanup. Two comments below.
>
> ...
>
>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
>> b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
>> index 3d69e51f3e4d..c9d5f1a38af3 100644
>> --- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
>> @@ -893,8 +893,8 @@ int i915_gem_mmap(struct file *filp, struct
>> vm_area_struct *vma)
>> * requires avoiding extraneous references to their filp, hence
>> why
>> * we prefer to use an anonymous file for their mmaps.
>> */
>> - fput(vma->vm_file);
>> - vma->vm_file = anon;
>> + vma_set_file(vma, anon);
>> + fput(anon);
>
> That's one fput() too many, isn't it?
No, the other cases were replacing the vm_file with something
pre-allocated and also grabbed a new reference.
But this case here uses the freshly allocated anon file and so
vma_set_file() grabs another extra reference which we need to drop.
The alternative is to just keep it as it is. Opinions?
>
>
> ...
>
>> diff --git a/drivers/staging/android/ashmem.c
>> b/drivers/staging/android/ashmem.c
>> index 10b4be1f3e78..a51dc089896e 100644
>> --- a/drivers/staging/android/ashmem.c
>> +++ b/drivers/staging/android/ashmem.c
>> @@ -450,9 +450,8 @@ static int ashmem_mmap(struct file *file, struct
>> vm_area_struct *vma)
>> vma_set_anonymous(vma);
>> }
>> - if (vma->vm_file)
>> - fput(vma->vm_file);
>> - vma->vm_file = asma->file;
>> + vma_set_file(vma, asma->file);
>> + fput(asma->file);
>
> Same here: that fput() seems wrong, as it was already done within
> vma_set_file().
No, that case is correct as well. The Android code here has the matching
get_file() a few lines up, see the surrounding code.
I didn't wanted to replace that since it does some strange error
handling here, so the result is that we need to drop the extra reference
as again.
We could also keep it like it is or maybe better put a TODO comment on it.
Regards,
Christian.
>
>
>
> thanks,
From: Rob Clark <robdclark(a)chromium.org>
This doesn't remove *all* the struct_mutex, but it covers the worst
of it, ie. shrinker/madvise/free/retire. The submit path still uses
struct_mutex, but it still needs *something* serialize a portion of
the submit path, and lock_stat mostly just shows the lock contention
there being with other submits. And there are a few other bits of
struct_mutex usage in less critical paths (debugfs, etc). But this
seems like a reasonable step in the right direction.
Rob Clark (14):
drm/msm: Use correct drm_gem_object_put() in fail case
drm/msm: Drop chatty trace
drm/msm: Move update_fences()
drm/msm: Add priv->mm_lock to protect active/inactive lists
drm/msm: Document and rename preempt_lock
drm/msm: Protect ring->submits with it's own lock
drm/msm: Refcount submits
drm/msm: Remove obj->gpu
drm/msm: Drop struct_mutex from the retire path
drm/msm: Drop struct_mutex in free_object() path
drm/msm: remove msm_gem_free_work
drm/msm: drop struct_mutex in madvise path
drm/msm: Drop struct_mutex in shrinker path
drm/msm: Don't implicit-sync if only a single ring
drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 4 +-
drivers/gpu/drm/msm/adreno/a5xx_preempt.c | 12 +--
drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 4 +-
drivers/gpu/drm/msm/msm_debugfs.c | 7 ++
drivers/gpu/drm/msm/msm_drv.c | 15 +---
drivers/gpu/drm/msm/msm_drv.h | 19 +++--
drivers/gpu/drm/msm/msm_gem.c | 76 ++++++------------
drivers/gpu/drm/msm/msm_gem.h | 53 +++++++++----
drivers/gpu/drm/msm/msm_gem_shrinker.c | 58 ++------------
drivers/gpu/drm/msm/msm_gem_submit.c | 17 ++--
drivers/gpu/drm/msm/msm_gpu.c | 96 ++++++++++++++---------
drivers/gpu/drm/msm/msm_gpu.h | 5 +-
drivers/gpu/drm/msm/msm_ringbuffer.c | 3 +-
drivers/gpu/drm/msm/msm_ringbuffer.h | 13 ++-
14 files changed, 188 insertions(+), 194 deletions(-)
--
2.26.2
On Thu, Oct 01, 2020 at 07:28:27PM +0200, Alexandre Bailon wrote:
> Hi Daniel,
>
> On 10/1/20 10:48 AM, Daniel Vetter wrote:
> > On Wed, Sep 30, 2020 at 01:53:46PM +0200, Alexandre Bailon wrote:
> > > This adds a RPMsg driver that implements communication between the CPU and an
> > > APU.
> > > This uses VirtIO buffer to exchange messages but for sharing data, this uses
> > > a dmabuf, mapped to be shared between CPU (userspace) and APU.
> > > The driver is relatively generic, and should work with any SoC implementing
> > > hardware accelerator for AI if they use support remoteproc and VirtIO.
> > >
> > > For the people interested by the firmware or userspace library,
> > > the sources are available here:
> > > https://github.com/BayLibre/open-amp/tree/v2020.01-mtk/apps/examples/apu
> > Since this has open userspace (from a very cursory look), and smells very
> > much like an acceleration driver, and seems to use dma-buf for memory
> > management: Why is this not just a drm driver?
>
> I have never though to DRM since for me it was only a RPMsg driver.
> I don't know well DRM. Could you tell me how you would do it so I could have
> a look ?
Well internally it would still be an rpmsg driver ... I'm assuming that's
kinda similar to how most gpu drivers sit on top of a pci_device or a
platform_device, it's just a means to get at your "device"?
The part I'm talking about here is the userspace api. You're creating an
entirely new chardev interface, which at least from a quick look seems to
be based on dma-buf buffers and used to submit commands to your device to
do some kind of computing/processing. That's exactly what drivers/gpu/drm
does (if you ignore the display/modeset side of things) - at the kernel
level gpus have nothing to do with graphics, but all with handling buffer
objects and throwing workloads at some kind of accelerator thing.
Of course that's just my guess of what's going on, after scrolling through
your driver and userspace a bit, I might be completely off. But if my
guess is roughly right, then your driver is internally an rpmsg
driver, but towards userspace it should be a drm driver.
Cheers, Daniel
>
> Thanks,
> Alexandre
>
> > -Daniel
> >
> > > Alexandre Bailon (3):
> > > Add a RPMSG driver for the APU in the mt8183
> > > rpmsg: apu_rpmsg: update the way to store IOMMU mapping
> > > rpmsg: apu_rpmsg: Add an IOCTL to request IOMMU mapping
> > >
> > > Julien STEPHAN (1):
> > > rpmsg: apu_rpmsg: Add support for async apu request
> > >
> > > drivers/rpmsg/Kconfig | 9 +
> > > drivers/rpmsg/Makefile | 1 +
> > > drivers/rpmsg/apu_rpmsg.c | 752 +++++++++++++++++++++++++++++++++
> > > drivers/rpmsg/apu_rpmsg.h | 52 +++
> > > include/uapi/linux/apu_rpmsg.h | 47 +++
> > > 5 files changed, 861 insertions(+)
> > > create mode 100644 drivers/rpmsg/apu_rpmsg.c
> > > create mode 100644 drivers/rpmsg/apu_rpmsg.h
> > > create mode 100644 include/uapi/linux/apu_rpmsg.h
> > >
> > > --
> > > 2.26.2
> > >
> > > _______________________________________________
> > > dri-devel mailing list
> > > dri-devel(a)lists.freedesktop.org
> > > https://lists.freedesktop.org/mailman/listinfo/dri-devel
> _______________________________________________
> dri-devel mailing list
> dri-devel(a)lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
On Wed, Sep 30, 2020 at 01:53:46PM +0200, Alexandre Bailon wrote:
> This adds a RPMsg driver that implements communication between the CPU and an
> APU.
> This uses VirtIO buffer to exchange messages but for sharing data, this uses
> a dmabuf, mapped to be shared between CPU (userspace) and APU.
> The driver is relatively generic, and should work with any SoC implementing
> hardware accelerator for AI if they use support remoteproc and VirtIO.
>
> For the people interested by the firmware or userspace library,
> the sources are available here:
> https://github.com/BayLibre/open-amp/tree/v2020.01-mtk/apps/examples/apu
Since this has open userspace (from a very cursory look), and smells very
much like an acceleration driver, and seems to use dma-buf for memory
management: Why is this not just a drm driver?
-Daniel
>
> Alexandre Bailon (3):
> Add a RPMSG driver for the APU in the mt8183
> rpmsg: apu_rpmsg: update the way to store IOMMU mapping
> rpmsg: apu_rpmsg: Add an IOCTL to request IOMMU mapping
>
> Julien STEPHAN (1):
> rpmsg: apu_rpmsg: Add support for async apu request
>
> drivers/rpmsg/Kconfig | 9 +
> drivers/rpmsg/Makefile | 1 +
> drivers/rpmsg/apu_rpmsg.c | 752 +++++++++++++++++++++++++++++++++
> drivers/rpmsg/apu_rpmsg.h | 52 +++
> include/uapi/linux/apu_rpmsg.h | 47 +++
> 5 files changed, 861 insertions(+)
> create mode 100644 drivers/rpmsg/apu_rpmsg.c
> create mode 100644 drivers/rpmsg/apu_rpmsg.h
> create mode 100644 include/uapi/linux/apu_rpmsg.h
>
> --
> 2.26.2
>
> _______________________________________________
> dri-devel mailing list
> dri-devel(a)lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
Hi Alex,
On 22.09.2020 01:15, Alex Goins wrote:
> Tested-by: Alex Goins <agoins(a)nvidia.com>
>
> This change fixes a regression with drm_prime_sg_to_page_addr_arrays() and
> AMDGPU in v5.9.
Thanks for testing!
> Commit 39913934 similarly revamped AMDGPU to use sgtable helper functions. When
> it changed from dma_map_sg_attrs() to dma_map_sgtable(), as a side effect it
> started correctly updating sgt->nents to the return value of dma_map_sg_attrs().
> However, drm_prime_sg_to_page_addr_arrays() incorrectly uses sgt->nents to
> iterate over pages, rather than sgt->orig_nents, resulting in it now returning
> the incorrect number of pages on AMDGPU.
>
> I had written a patch that changes drm_prime_sg_to_page_addr_arrays() to use
> for_each_sgtable_sg() instead of for_each_sg(), iterating using sgt->orig_nents:
>
> - for_each_sg(sgt->sgl, sg, sgt->nents, count) {
> + for_each_sgtable_sg(sgt, sg, count) {
>
> This patch takes it further, but still has the effect of fixing the number of
> pages that drm_prime_sg_to_page_addr_arrays() returns. Something like this
> should be included in v5.9 to prevent a regression with AMDGPU.
Probably the easiest way to handle a fix for v5.9 would be to simply
merge the latest version of this patch also to v5.9-rcX:
https://lore.kernel.org/dri-devel/20200904131711.12950-3-m.szyprowski@samsu…
This way we would get it fixed and avoid possible conflict in the -next.
Do you have any AMDGPU fixes for v5.9 in the queue? Maybe you can add
that patch to the queue? Dave: would it be okay that way?
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
Am 28.09.20 um 09:37 schrieb Thomas Zimmermann:
> Hi
>
> Am 28.09.20 um 08:50 schrieb Christian König:
>> Am 27.09.20 um 21:16 schrieb Sam Ravnborg:
>>> Hi Thomas.
>>>
>>>>> struct simap {
>>>>> union {
>>>>> void __iomem *vaddr_iomem;
>>>>> void *vaddr;
>>>>> };
>>>>> bool is_iomem;
>>>>> };
>>>>>
>>>>> Where simap is a shorthand for system_iomem_map
>>>>> And it could al be stuffed into a include/linux/simap.h file.
>>>>>
>>>>> Not totally sold on the simap name - but wanted to come up with
>>>>> something.
>>>> Yes. Others, myself included, have suggested to use a name that does not
>>>> imply a connection to the dma-buf framework, but no one has come up with
>>>> a good name.
>>>>
>>>> I strongly dislike simap, as it's entirely non-obvious what it does.
>>>> dma-buf-map is not actually wrong. The structures represents the mapping
>>>> of a dma-able buffer in most cases.
>>>>
>>>>> With this approach users do not have to pull in dma-buf to use it and
>>>>> users will not confuse that this is only for dma-buf usage.
>>>> There's no need to enable dma-buf. It's all in the header file without
>>>> dependencies on dma-buf. It's really just the name.
>>>>
>>>> But there's something else to take into account. The whole issue here is
>>>> that the buffer is disconnected from its originating driver, so we don't
>>>> know which kind of memory ops we have to use. Thinking about it, I
>>>> realized that no one else seemed to have this problem until now.
>>>> Otherwise there would be a solution already. So maybe the dma-buf
>>>> framework *is* the native use case for this data structure.
>>> We have at least:
>>> linux/fb.h:
>>> union {
>>> char __iomem *screen_base; /* Virtual address */
>>> char *screen_buffer;
>>> };
>>>
>>> Which solve more or less the same problem.
> I thought this was for convenience. The important is_iomem bit is missing.
>
>> I also already noted that in TTM we have exactly the same problem and a
>> whole bunch of helpers to allow operations on those pointers.
> How do you call this within TTM?
ttm_bus_placement, but I really don't like that name.
>
> The data structure represents a pointer to either system or I/O memory,
> but not necessatrily device memory. It contains raw data. That would
> give something like
>
> struct databuf_map
> struct databuf_ptr
> struct dbuf_map
> struct dbuf_ptr
>
> My favorite would be dbuf_ptr. It's short and the API names would make
> sense: dbuf_ptr_clear() for clearing, dbuf_ptr_set_vaddr() to set an
> address, dbuf_ptr_incr() to increment, etc. Also, the _ptr indicates
> that it's a single address; not an offset with length.
Puh, no idea. All of that doesn't sound like it 100% hits the underlying
meaning of the structure.
Christian.
>
> Best regards
> Thomas
>
>> Christian.
>>
>>>
>>>> Anyway, if a better name than dma-buf-map comes in, I'm willing to
>>>> rename the thing. Otherwise I intend to merge the patchset by the end of
>>>> the week.
>>> Well, the main thing is that I think this shoud be moved away from
>>> dma-buf. But if indeed dma-buf is the only relevant user in drm then
>>> I am totally fine with the current naming.
>>>
>>> One alternative named that popped up in my head: struct sys_io_map {}
>>> But again, if this is kept in dma-buf then I am fine with the current
>>> naming.
>>>
>>> In other words, if you continue to think this is mostly a dma-buf
>>> thing all three patches are:
>>> Acked-by: Sam Ravnborg <sam(a)ravnborg.org>
>>>
>>> Sam
>> _______________________________________________
>> dri-devel mailing list
>> dri-devel(a)lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/dri-devel
Hi Thomas.
> >
> > struct simap {
> > union {
> > void __iomem *vaddr_iomem;
> > void *vaddr;
> > };
> > bool is_iomem;
> > };
> >
> > Where simap is a shorthand for system_iomem_map
> > And it could al be stuffed into a include/linux/simap.h file.
> >
> > Not totally sold on the simap name - but wanted to come up with
> > something.
>
> Yes. Others, myself included, have suggested to use a name that does not
> imply a connection to the dma-buf framework, but no one has come up with
> a good name.
>
> I strongly dislike simap, as it's entirely non-obvious what it does.
> dma-buf-map is not actually wrong. The structures represents the mapping
> of a dma-able buffer in most cases.
>
> >
> > With this approach users do not have to pull in dma-buf to use it and
> > users will not confuse that this is only for dma-buf usage.
>
> There's no need to enable dma-buf. It's all in the header file without
> dependencies on dma-buf. It's really just the name.
>
> But there's something else to take into account. The whole issue here is
> that the buffer is disconnected from its originating driver, so we don't
> know which kind of memory ops we have to use. Thinking about it, I
> realized that no one else seemed to have this problem until now.
> Otherwise there would be a solution already. So maybe the dma-buf
> framework *is* the native use case for this data structure.
We have at least:
linux/fb.h:
union {
char __iomem *screen_base; /* Virtual address */
char *screen_buffer;
};
Which solve more or less the same problem.
> Anyway, if a better name than dma-buf-map comes in, I'm willing to
> rename the thing. Otherwise I intend to merge the patchset by the end of
> the week.
Well, the main thing is that I think this shoud be moved away from
dma-buf. But if indeed dma-buf is the only relevant user in drm then
I am totally fine with the current naming.
One alternative named that popped up in my head: struct sys_io_map {}
But again, if this is kept in dma-buf then I am fine with the current
naming.
In other words, if you continue to think this is mostly a dma-buf
thing all three patches are:
Acked-by: Sam Ravnborg <sam(a)ravnborg.org>
Sam
On Fri, Sep 25, 2020 at 04:51:38PM +0800, Tian Tao wrote:
> drm_modeset_lock.h already declares struct drm_device, so there's no
> need to declare it in vc4_drv.h
>
> Signed-off-by: Tian Tao <tiantao6(a)hisilicon.com>
Just an aside, when submitting patches please use
scripts/get_maintainers.pl to generate the recipient list. Looking through
past few patches from you it seems fairly arbitrary and often misses the
actual maintainers for a given piece of code, which increases the odds the
patch will get lost a lot.
E.g. for this one I'm only like the 5th or so fallback person, and the
main maintainer isn't on the recipient list.
Cheeers, Daniel
> ---
> drivers/gpu/drm/vc4/vc4_drv.h | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
> index 8c8d96b..8717a1c 100644
> --- a/drivers/gpu/drm/vc4/vc4_drv.h
> +++ b/drivers/gpu/drm/vc4/vc4_drv.h
> @@ -19,7 +19,6 @@
>
> #include "uapi/drm/vc4_drm.h"
>
> -struct drm_device;
> struct drm_gem_object;
>
> /* Don't forget to update vc4_bo.c: bo_type_names[] when adding to
> --
> 2.7.4
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
NULL pointer dereference is observed while exporting the dmabuf but
failed to allocate the 'struct file' which results into the dropping of
the allocated dentry corresponding to this file in the dmabuf fs, which
is ending up in dma_buf_release() and accessing the uninitialzed
dentry->d_fsdata.
Call stack on 5.4 is below:
dma_buf_release+0x2c/0x254 drivers/dma-buf/dma-buf.c:88
__dentry_kill+0x294/0x31c fs/dcache.c:584
dentry_kill fs/dcache.c:673 [inline]
dput+0x250/0x380 fs/dcache.c:859
path_put+0x24/0x40 fs/namei.c:485
alloc_file_pseudo+0x1a4/0x200 fs/file_table.c:235
dma_buf_getfile drivers/dma-buf/dma-buf.c:473 [inline]
dma_buf_export+0x25c/0x3ec drivers/dma-buf/dma-buf.c:585
Fix this by checking for the valid pointer in the dentry->d_fsdata.
Fixes: 4ab59c3c638c ("dma-buf: Move dma_buf_release() from fops to dentry_ops")
Cc: <stable(a)vger.kernel.org> [5.7+]
Signed-off-by: Charan Teja Reddy <charante(a)codeaurora.org>
---
drivers/dma-buf/dma-buf.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 58564d82..844967f 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -59,6 +59,8 @@ static void dma_buf_release(struct dentry *dentry)
struct dma_buf *dmabuf;
dmabuf = dentry->d_fsdata;
+ if (unlikely(!dmabuf))
+ return;
BUG_ON(dmabuf->vmapping_counter);
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
member of the Code Aurora Forum, hosted by The Linux Foundation
Hi Andrew,
I'm the new DMA-buf maintainer and Daniel and others came up with patches extending the use of the dma_buf_mmap() function.
Now this function is doing something a bit odd by changing the vma->vm_file while installing a VMA in the mmap() system call
The background here is that DMA-buf allows device drivers to export buffer which are then imported into another device driver. The mmap() handler of the importing device driver then find that the pgoff belongs to the exporting device and so redirects the mmap() call there.
In other words user space calls mmap() on one file descriptor, but get a different one mapped into your virtual address space.
My question is now: Is that legal or can you think of something which breaks here?
If it's not legal we should probably block any new users of the dma_buf_mmap() function and consider what should happen with the two existing ones.
If that is legal I would like to document this by adding a new vma_set_file() function which does the necessary reference count dance.
Thanks in advance,
Christian.