On Tue, Jan 28, 2020 at 9:09 PM Geert Uytterhoeven <geert+renesas@xxxxxxxxx> wrote: > > If cc_queues_status() indicates that the queue is full, > cc_send_sync_request() should loop and retry. > > However, cc_queues_status() returns either 0 (for success), or -ENOSPC > (for queue full), while cc_send_sync_request() checks for real errors by > comparing with -EAGAIN. Hence -ENOSPC is always considered a real > error, and the code never retries the operation. > > Fix this by just removing the check, as cc_queues_status() never returns > any other error value than -ENOSPC. Thank you for spotting this! The error is simply checking for the wrong error value. We should be checking for -ENOSPC! What this does aims to do is wait for the hardware queue to free up if we were asked to queue a synchronous request and there was no room in the hardware queue. The cc_queue_status() function used to return -EAGAIN in this scenario and this was missed in the change. I'm curious as to how you found this - did you run into some problem and traced it to this? This can lead to a setkey() failing in very high load situations but I expect this occurrence to be very rare indeed since cc_queue_status() already loops several times waiting for the room to be freeed. Gilad -- Gilad Ben-Yossef Chief Coffee Drinker values of β will give rise to dom!
