On 1/24/20 7:39 PM, Chris Wilson wrote:
Quoting Thomas Hellström (VMware) (2020-01-24 13:37:47)
On 1/24/20 2:01 PM, Chris Wilson wrote:
Since drm_global_mutex is a true global mutex across devices, we don't want to acquire it unless absolutely necessary. For maintaining the device local open_count, we can use atomic operations on the counter itself, except when making the transition to/from 0. Here, we tackle the easy portion of delaying acquiring the drm_global_mutex for the final release by using atomic_dec_and_mutex_lock(), leaving the global serialisation across the device opens.
Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Thomas Hellström (VMware) thomas_os@shipmail.org
For the series:
Reviewed-by: Thomas Hellström thellstrom@vmware.com
Now being opt-in, it is fairly limited in scope and will not randomly break others (touch wood) and the close() racing in BAT didn't throw anything up, so pushed to drm-misc-next. Thanks for the review and suggestions,
Next task is to suggest others might like to use it as well. -Chris
Thanks. I'll look at doing the same for those drivers I audited.
/Thomas