<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <style type="text/css" style="display:none;"></style> </head> <body dir="ltr"> <div id="divtagdefaultwrapper" style="font-size:12pt;color:#000000;font-family:Calibri,Helvetica,sans-serif;" dir="ltr"> <p style="margin-top:0;margin-bottom:0"></p> <div>Hi Christian & Chris</div> <div><br> </div> <div>two question regarding resv:</div> <div><br> </div> <div>1) considering below sequence:</div> <div><br> </div> <div>call reservation_object_add_shared_fence,</div> <div>now assume old->shared_count is now 3</div> <div>call reservation_object_add_shared_fence,</div> <div>now assume old->shared_count is now 4,</div> <div><br> </div> <div>call reservation_object_reserve_shared,</div> <div>now obj->staged is new allocated, and its shared_max = 8, but not</div> <div>used by far.</div> <div><br> </div> <div>call reservation_object_add_excl_fence,</div> <div>it set obj->fence->shared_count to 0, <b>and put all shared fence from obj->fence without waiting signaling.</b></div> <div>(this action looks inappropriate, I think at least before put all those shared fences</div> <div>we should dma_wait_fence() on them to make sure they are signaled)</div> <div><br> </div> <div>call reservation_object_reserve_shared,</div> <div><b>this time obj->staged isn't NULL, and it is freed</b> (nothing bad now</div> <div>since obj->fence points to other place),</div> <div>and obj->staged set to NULL,</div> <div><br> </div> <div>call reservation_object_add_shared_fence,</div> <div>this time should going through reservation_object_add_shared_inplace,</div> <div><b>But BUG_ON(old->shared_count >= old->shared_max) will hit !</b></div> <div><b><br> </b></div> <div>This looks a design flaw in reservation object, shouldn't we fix it ?</div> <div><b><br> </b></div> <div><br> </div> <div></div> <div>2) in add_excl_fence(), it simply set old->shared_count to 0, and put all shared fences of old</div> <div>is that correct? if excl fence is really exclusively used, why we still consider both shared fence and</div> <div>excl fence on wait_timeout_rcu() routine, see blew description of this routine</div> <div><br> </div> <div> <div style="color: rgb(212, 212, 212); background-color: rgb(30, 30, 30); font-family: "Droid Sans Mono", monospace, monospace, "Droid Sans Fallback"; font-size: 14px; line-height: 19px; white-space: pre;"> <br> <div><span style="color: #608b4e;">/**</span></div> <div><span style="color: #608b4e;">* reservation_object_wait_timeout_rcu - Wait on reservation's objects</span></div> <div><span style="color: #608b4e;">* shared and/or exclusive fences.</span></div> <div><span style="color: #608b4e;">* @obj: the reservation object</span></div> <div><span style="color: #608b4e;">* @wait_all: if true, wait on all fences, else wait on just exclusive fence</span></div> <div><span style="color: #608b4e;">* @intr: if true, do interruptible wait</span></div> <div><span style="color: #608b4e;">* @timeout: timeout value in jiffies or zero to return immediately</span></div> <div><span style="color: #608b4e;">*</span></div> <div><span style="color: #608b4e;">* RETURNS</span></div> <div><span style="color: #608b4e;">* Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or</span></div> <div><span style="color: #608b4e;">* greater than zer on success.</span></div> <div><span style="color: #608b4e;">*/</span></div> <div><span style="color: #569cd6;">long</span> <span style="color: #dcdcaa;">reservation_object_wait_timeout_rcu</span>(<span style="color: #569cd6;">struct</span> reservation_object *obj,</div> <div> <span style="color: #569cd6;">bool</span> wait_all, <span style="color: #569cd6;"> bool</span> intr,</div> <div> <span style="color: #569cd6;">unsigned</span> <span style="color: #569cd6;"> long</span> timeout)</div> </div> <br> </div> <div><span style="font-size: 12pt;"> </span><br> </div> <div><span style="font-size: 12pt;">thanks</span></div> <div>/Monk</div> <div><br> </div> <div><br> </div> <div><br> </div> <br> <p></p> </div> </body> </html>