[09/13] drm/gem: Acquire reservation lock in drm_gem_{pin/unpin}()

[Sui Jingfeng]

Hi,


On 2024/2/27 18:14, Thomas Zimmermann wrote:
> Acquire the buffer object's reservation lock in drm_gem_pin() and
> remove locking the drivers' GEM callbacks where necessary. Same for
> unpin().
>
> DRM drivers and memory managers modified by this patch will now have
> correct dma-buf locking semantics: the caller is responsible for
> holding the reservation lock when calling the pin or unpin callback.
>
> DRM drivers and memory managers that are not modified will now be
> protected against concurent invocation of their pin and unpin callbacks.

'concurent' -> 'concurrent'

> PRIME does not implement struct dma_buf_ops.pin, which requires
> the caller to hold the reservation lock. It does implement struct
> dma_buf_ops.attach, which requires to callee to acquire the
> reservation lock.

which requires 'the' callee to acquire the reservation lock.


> The PRIME code uses drm_gem_pin(), so locks
> are now taken as specified. Same for unpin and detach.
>
> The patch harmonizes GEM pin and unpin to have non-interruptible
> reservation locking across all drivers, as is already the case for
> vmap and vunmap. This affects gem-shmem, gem-vram, loongson, qxl and
> radeon.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
> Reviewed-by: Zack Rusin <zack.rusin at broadcom.com>


Tested with drm/loongson, play with a few days.
Switch to virtual terminal, then switch back is fine.
not found problems yet. So,

Tested-by: Sui Jingfeng <sui.jingfeng at linux.dev>