On Mon, Dec 15, 2025 at 02:28:50AM +0000, Swaraj Gaikwad wrote: > The msm driver implements a custom dumb_map_offset callback. This > implementation acquires the msm_gem_lock, but the underlying > drm_gem_create_mmap_offset() function is already thread-safe regarding > the VMA offset manager (it acquires the mgr->vm_lock internally).
Other pieces are using msm_gem_lock() / msm_gem_unlock(), which translates to dma_resv_lock() / dma_resv_unlock(), so you need to describe, why it's still safe wrt. that code. > > Switching to the generic drm_gem_dumb_map_offset() helper provides > several benefits: > 1. Removes the unnecessary locking overhead (locking leftovers). > 2. Adds a missing check to reject mapping of imported objects, which is > invalid for dumb buffers. > 3. Allows for the removal of the msm_gem_dumb_map_offset() wrapper and > the msm_gem_mmap_offset() helper function. > > The logic from msm_gem_mmap_offset() has been inlined into > msm_ioctl_gem_info() to maintain functionality without the separate > helper. > > This addresses the TODO: > "Documentation/gpu/todo.rst: Remove custom dumb_map_offset implementations" > > Signed-off-by: Swaraj Gaikwad <[email protected]> > --- > > Compile-tested only. > -- With best wishes Dmitry
