dma-buf: Split out dma fence array create into alloc and arm functions

Useful to preallocate dma fence array and then arm in path of reclaim or
a dma fence.

v2:
- s/arm/init (Christian)
- Drop !a

dma-buf: Split out dma fence array create into alloc and arm functions

Useful to preallocate dma fence array and then arm in path of reclaim or
a dma fence.

v2:
- s/arm/init (Christian)
- Drop !array warn (Christian)
v3:
- Fix kernel doc typos (dim)

Cc: Sumit Semwal <[email protected]>
Cc: Christian König <[email protected]>
Signed-off-by: Matthew Brost <[email protected]>
Reviewed-by: Christian König <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

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dma-buf/fence-array: Add flex array to struct dma_fence_array

This is an effort to get rid of all multiplications from allocation
functions in order to prevent integer overflows [1][2].

The "struct

dma-buf/fence-array: Add flex array to struct dma_fence_array

This is an effort to get rid of all multiplications from allocation
functions in order to prevent integer overflows [1][2].

The "struct dma_fence_array" can be refactored to add a flex array in order
to have the "callback structures allocated behind the array" be more
explicit.

Do so:
- makes the code more readable and safer.
- allows using __counted_by() for additional checks
- avoids some pointer arithmetic in dma_fence_array_enable_signaling()

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1]
Link: https://github.com/KSPP/linux/issues/160 [2]
Signed-off-by: Christophe JAILLET <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Reviewed-by: Christian König <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/8b4e556e07b5dd78bb8a39b67ea0a43b199083c8.1716652811.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Christian König <[email protected]>

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dma-buf: add dma_fence_unwrap v2

Add a general purpose helper to deep dive into dma_fence_chain/dma_fence_array
structures and iterate over all the fences in them.

This is useful when we need to fl

dma-buf: add dma_fence_unwrap v2

Add a general purpose helper to deep dive into dma_fence_chain/dma_fence_array
structures and iterate over all the fences in them.

This is useful when we need to flatten out all fences in those structures.

v2: some selftests cleanup, improved function naming and documentation

Signed-off-by: Christian König <[email protected]>
Reviewed-by: Daniel Vetter <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

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dma-buf: Add dma_fence_array_for_each (v2)

Add a helper to iterate over all fences in a dma_fence_array object.

v2 (Jason Ekstrand)
- Return NULL from dma_fence_array_first if head == NULL. This

dma-buf: Add dma_fence_array_for_each (v2)

Add a helper to iterate over all fences in a dma_fence_array object.

v2 (Jason Ekstrand)
- Return NULL from dma_fence_array_first if head == NULL. This matches
the iterator behavior of dma_fence_chain_for_each in that it iterates
zero times if head == NULL.
- Return NULL from dma_fence_array_next if index > array->num_fences.

Signed-off-by: Jason Ekstrand <[email protected]>
Reviewed-by: Jason Ekstrand <[email protected]>
Reviewed-by: Christian König <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: Maarten Lankhorst <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
Signed-off-by: Christian König <[email protected]>

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dma-buf: consolidate dma_fence subclass checking

Consolidate the wrapper functions to check for dma_fence
subclasses in the dma_fence header.

This makes it easier to document and also check the dif

dma-buf: consolidate dma_fence subclass checking

Consolidate the wrapper functions to check for dma_fence
subclasses in the dma_fence header.

This makes it easier to document and also check the different
requirements for fence containers in the subclasses.

Signed-off-by: Christian König <[email protected]>
Reviewed-by: Thomas Hellström <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

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treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of th

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174

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

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 655 file(s).

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Allison Randal <[email protected]>
Reviewed-by: Kate Stewart <[email protected]>
Reviewed-by: Richard Fontana <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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dma-buf: Fix kerneldoc comment for struct dma_fence_array

The kerneldoc comment for struct dma_fence_array lacks a description
of the "work" member, leading to this docs-build warning:

./include/

dma-buf: Fix kerneldoc comment for struct dma_fence_array

The kerneldoc comment for struct dma_fence_array lacks a description
of the "work" member, leading to this docs-build warning:

./include/linux/dma-fence-array.h:54: warning: Function parameter or member 'work' not described in 'dma_fence_array'

Add a description and make the warning go away.

Signed-off-by: Jonathan Corbet <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

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dma-buf/fence: Fix lock inversion within dma-fence-array

Ages ago Rob Clark noted,

"Currently with fence-array, we have a potential deadlock situation. If
we fence_add_callback() on an array-fence

dma-buf/fence: Fix lock inversion within dma-fence-array

Ages ago Rob Clark noted,

"Currently with fence-array, we have a potential deadlock situation. If
we fence_add_callback() on an array-fence, the array-fence's lock is
acquired first, and in it's ->enable_signaling() callback, it will install
cbs on it's array-member fences, so the array-member's lock is acquired
second.

But in the signal path, the array-member's lock is acquired first, and
the array-fence's lock acquired second."

Rob proposed either extensive changes to dma-fence to unnest the
fence-array signaling, or to defer the signaling onto a workqueue. This
is a more refined version of the later, that should keep the latency
of the fence signaling to a minimum by using an irq-work, which is
executed asap.

Reported-by: Rob Clark <[email protected]>
Suggested-by: Rob Clark <[email protected]>
References: [email protected]
Signed-off-by: Chris Wilson <[email protected]>
Cc: Rob Clark <[email protected]>
Cc: Gustavo Padovan <[email protected]>
Cc: Sumit Semwal <[email protected]>
Cc: Christian König <[email protected]>
Reviewed-by: Christian König <[email protected]>
Signed-off-by: Sumit Semwal <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

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dma-fence: add dma_fence_match_context helper

Add a helper to check if all fences in a fence array are from a given
context. For convenience, the function can also handle being given a
non-array fen

dma-fence: add dma_fence_match_context helper

Add a helper to check if all fences in a fence array are from a given
context. For convenience, the function can also handle being given a
non-array fence.

Signed-off-by: Philipp Zabel <[email protected]>
Reviewed-by: Gustavo Padovan <[email protected]>
Acked-by: Sumit Semwal <[email protected]>
Signed-off-by: Sumit Semwal <[email protected]>
Link: http://patchwork.freedesktop.org/patch/msgid/[email protected]

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dma-buf: Rename struct fence to dma_fence

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 r

dma-buf: Rename struct fence to dma_fence

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 <[email protected]>
Reviewed-by: Gustavo Padovan <[email protected]>
Acked-by: Sumit Semwal <[email protected]>
Acked-by: Christian König <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>
Link: http://patchwork.freedesktop.org/patch/msgid/[email protected]

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