Initialize mt_exit flags unconditionally

This change initializes the 'mt_exit' flags unconditionally
as suggested in https://aomedia-review.googlesource.com/c/aom/+/183861.
This will resolve the potential issue of 'mt_exit' having a stale
value from the previous aom_codec_encode() call.

Bug: aomedia:3276
Change-Id: I817b3605b08267bd75ecb694aa10fc07d10137ca

av1/common/thread_common.c

diff --git a/av1/common/thread_common.c b/av1/common/thread_common.c
index 8a6f290..7dafb9a 100644
--- a/av1/common/thread_common.c
+++ b/av1/common/thread_common.c
@@ -57,7 +57,6 @@
 void av1_loop_filter_alloc(AV1LfSync *lf_sync, AV1_COMMON *cm, int rows,
                            int width, int num_workers) {
   lf_sync->rows = rows;
-  lf_sync->lf_mt_exit = false;
 #if CONFIG_MULTITHREAD
   {
     int i, j;
@@ -617,7 +616,6 @@
   }
 
   lr_sync->num_workers = num_workers;
-  lr_sync->lr_mt_exit = false;
 
   for (int j = 0; j < num_planes; j++) {
     CHECK_MEM_ERROR(
@@ -932,6 +930,7 @@
     av1_loop_restoration_alloc(lr_sync, cm, num_workers, num_rows_lr,
                                num_planes, cm->width);
   }
+  lr_sync->lr_mt_exit = false;
 
   // Initialize cur_sb_col to -1 for all SB rows.
   for (i = 0; i < num_planes; i++) {
@@ -985,6 +984,7 @@
   cdef_sync->end_of_frame = 0;
   cdef_sync->fbr = 0;
   cdef_sync->fbc = 0;
+  cdef_sync->cdef_mt_exit = false;
 }
 
 static AOM_INLINE void launch_cdef_workers(AVxWorker *const workers,

av1/common/thread_common.h

diff --git a/av1/common/thread_common.h b/av1/common/thread_common.h
index cfc37f9..675687d 100644
--- a/av1/common/thread_common.h
+++ b/av1/common/thread_common.h
@@ -269,6 +269,7 @@
     av1_loop_filter_dealloc(lf_sync);
     av1_loop_filter_alloc(lf_sync, cm, sb_rows, cm->width, num_workers);
   }
+  lf_sync->lf_mt_exit = false;
 
   // Initialize cur_sb_col to -1 for all SB rows.
   for (int i = 0; i < MAX_MB_PLANE; i++) {

av1/encoder/ethread.c

diff --git a/av1/encoder/ethread.c b/av1/encoder/ethread.c
index fe62b82..61bb8a2 100644
--- a/av1/encoder/ethread.c
+++ b/av1/encoder/ethread.c
@@ -273,8 +273,6 @@
   enc_row_mt->allocated_rows = max_rows;
   enc_row_mt->allocated_cols = max_cols - 1;
   enc_row_mt->allocated_sb_rows = sb_rows;
-  enc_row_mt->row_mt_exit = false;
-  enc_row_mt->firstpass_mt_exit = false;
 }
 
 void av1_row_mt_mem_dealloc(AV1_COMP *cpi) {
@@ -904,7 +902,6 @@
                       aom_malloc(sizeof(*(tpl_row_mt->mutex_))));
       if (tpl_row_mt->mutex_) pthread_mutex_init(tpl_row_mt->mutex_, NULL);
     }
-    tpl_row_mt->tpl_mt_exit = false;
 
 #if !CONFIG_REALTIME_ONLY
     if (is_restoration_used(cm)) {
@@ -1924,6 +1921,7 @@
          sizeof(*thread_id_to_tile_id) * MAX_NUM_THREADS);
   memset(enc_row_mt->num_tile_cols_done, 0,
          sizeof(*enc_row_mt->num_tile_cols_done) * sb_rows_in_frame);
+  enc_row_mt->row_mt_exit = false;
 
   for (int tile_row = 0; tile_row < tile_rows; tile_row++) {
     for (int tile_col = 0; tile_col < tile_cols; tile_col++) {
@@ -2002,6 +2000,7 @@
 
   memset(thread_id_to_tile_id, -1,
          sizeof(*thread_id_to_tile_id) * MAX_NUM_THREADS);
+  enc_row_mt->firstpass_mt_exit = false;
 
   for (int tile_row = 0; tile_row < tile_rows; tile_row++) {
     for (int tile_col = 0; tile_col < tile_cols; tile_col++) {
@@ -2300,6 +2299,7 @@
     av1_tpl_alloc(tpl_sync, cm, mb_rows);
   }
   tpl_sync->num_threads_working = num_workers;
+  mt_info->tpl_row_mt.tpl_mt_exit = false;
 
   // Initialize cur_mb_col to -1 for all MB rows.
   memset(tpl_sync->num_finished_cols, -1,
@@ -3097,6 +3097,7 @@
   AV1EncPackBSSync *const pack_bs_sync = &mt_info->pack_bs_sync;
   const uint16_t num_tiles = cm->tiles.rows * cm->tiles.cols;
   pack_bs_sync->next_job_idx = 0;
+  pack_bs_sync->pack_bs_mt_exit = false;
 
   PackBSTileOrder *const pack_bs_tile_order = pack_bs_sync->pack_bs_tile_order;
   // Reset tile order data of pack bitstream
@@ -3232,6 +3233,7 @@
   cdef_sync->end_of_frame = 0;
   cdef_sync->fbr = 0;
   cdef_sync->fbc = 0;
+  cdef_sync->cdef_mt_exit = false;
 }
 
 // Checks if a job is available. If job is available,