Re: [Linaro-mm-sig] [PATCH 6/7] drm/vgem: import support

On Wed, 22 Feb 2012 20:29:19 +0100, Ben Widawsky ben@bwidawsk.net wrote:

• mutex_lock(&dev->prime_mutex);
• /* First check that we don't dup on this file */
• ret = drm_prime_lookup_fd_handle_mapping(&file_priv->prime, dma_buf,

• 				 handle);
  

The other example of importing bo we have already in GEM is through the use of flink and global names. There we create a new handle every time a process opens a name, and de-duplication is indeed handled in userspace if it so desires.

Multiple handles pointing to the same object simplifies the code without risking kernel integrity, so why bother with kernel de-dupe? And allow userspace the extra bit of freedom to shoot itself in the foot! -Chris