gpu: nvgpu: replace tsg list mutex with rwsem

Lock only for modifications to the tsg channel list, and allow multiple
concurrent readers.

Bug 1848834
Bug 1814773

Change-Id: Ie3938d4239cfe36a14211f4649ce72b7fc3e2fa4
Signed-off-by: Konsta Holtta <kholtta@nvidia.com>
Reviewed-on: http://git-master/r/1269579
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

4 files changed, 27 insertions, 27 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c b/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c
index 1818a57e..488ae309 100644
--- a/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c
@@ -1261,7 +1261,7 @@ bool gk20a_fifo_set_ctx_mmu_error_tsg(struct gk20a *g,
         gk20a_err(dev_from_gk20a(g),
                 "TSG %d generated a mmu fault", tsg->tsgid);
 
-        mutex_lock(&tsg->ch_list_lock);
+        down_read(&tsg->ch_list_lock);
         list_for_each_entry(ch, &tsg->ch_list, ch_entry) {
                 if (gk20a_channel_get(ch)) {
                         if (!gk20a_fifo_set_ctx_mmu_error(g, ch))
@@ -1269,7 +1269,7 @@ bool gk20a_fifo_set_ctx_mmu_error_tsg(struct gk20a *g,
                         gk20a_channel_put(ch);
                 }
         }
-        mutex_unlock(&tsg->ch_list_lock);
+        up_read(&tsg->ch_list_lock);
 
         return ret;
 }
@@ -1286,7 +1286,7 @@ void gk20a_fifo_abort_tsg(struct gk20a *g, u32 tsgid, bool preempt)
         if (preempt)
                 g->ops.fifo.preempt_tsg(g, tsgid);
 
-        mutex_lock(&tsg->ch_list_lock);
+        down_read(&tsg->ch_list_lock);
         list_for_each_entry(ch, &tsg->ch_list, ch_entry) {
                 if (gk20a_channel_get(ch)) {
                         ch->has_timedout = true;
@@ -1294,7 +1294,7 @@ void gk20a_fifo_abort_tsg(struct gk20a *g, u32 tsgid, bool preempt)
                         gk20a_channel_put(ch);
                 }
         }
-        mutex_unlock(&tsg->ch_list_lock);
+        up_read(&tsg->ch_list_lock);
 }
 
 int gk20a_fifo_deferred_reset(struct gk20a *g, struct channel_gk20a *ch)
@@ -1793,7 +1793,7 @@ int gk20a_fifo_force_reset_ch(struct channel_gk20a *ch,
         if (gk20a_is_channel_marked_as_tsg(ch)) {
                 tsg = &g->fifo.tsg[ch->tsgid];
 
-                mutex_lock(&tsg->ch_list_lock);
+                down_read(&tsg->ch_list_lock);
 
                 list_for_each_entry(ch_tsg, &tsg->ch_list, ch_entry) {
                         if (gk20a_channel_get(ch_tsg)) {
@@ -1802,7 +1802,7 @@ int gk20a_fifo_force_reset_ch(struct channel_gk20a *ch,
                         }
                 }
 
-                mutex_unlock(&tsg->ch_list_lock);
+                up_read(&tsg->ch_list_lock);
                 gk20a_fifo_recover_tsg(g, ch->tsgid, verbose);
         } else {
                 gk20a_set_error_notifier(ch, err_code);
@@ -1910,7 +1910,7 @@ static bool gk20a_fifo_check_tsg_ctxsw_timeout(struct tsg_gk20a *tsg,
         *verbose = false;
         *ms = GRFIFO_TIMEOUT_CHECK_PERIOD_US / 1000;
 
-        mutex_lock(&tsg->ch_list_lock);
+        down_read(&tsg->ch_list_lock);
 
         /* check if there was some progress on any of the TSG channels.
          * fifo recovery is needed if at least one channel reached the
@@ -1966,7 +1966,7 @@ static bool gk20a_fifo_check_tsg_ctxsw_timeout(struct tsg_gk20a *tsg,
          * of them has reached the timeout, there is nothing more to do:
          * timeout_accumulated_ms has been updated for all of them.
          */
-        mutex_unlock(&tsg->ch_list_lock);
+        up_read(&tsg->ch_list_lock);
         return recover;
 }
 
@@ -2256,7 +2256,7 @@ static u32 gk20a_fifo_handle_pbdma_intr(struct device *dev,
                         struct tsg_gk20a *tsg = &f->tsg[id];
                         struct channel_gk20a *ch = NULL;
 
-                        mutex_lock(&tsg->ch_list_lock);
+                        down_read(&tsg->ch_list_lock);
                         list_for_each_entry(ch, &tsg->ch_list, ch_entry) {
                                 if (gk20a_channel_get(ch)) {
                                         gk20a_set_error_notifier(ch,
@@ -2264,7 +2264,7 @@ static u32 gk20a_fifo_handle_pbdma_intr(struct device *dev,
                                         gk20a_channel_put(ch);
                                 }
                         }
-                        mutex_unlock(&tsg->ch_list_lock);
+                        up_read(&tsg->ch_list_lock);
                         gk20a_fifo_recover_tsg(g, id, true);
                 }
         }
@@ -2395,7 +2395,7 @@ static int __locked_fifo_preempt(struct gk20a *g, u32 id, bool is_tsg)
                         gk20a_err(dev_from_gk20a(g),
                                 "preempt TSG %d timeout\n", id);
 
-                        mutex_lock(&tsg->ch_list_lock);
+                        down_read(&tsg->ch_list_lock);
                         list_for_each_entry(ch, &tsg->ch_list, ch_entry) {
                                 if (!gk20a_channel_get(ch))
                                         continue;
@@ -2403,7 +2403,7 @@ static int __locked_fifo_preempt(struct gk20a *g, u32 id, bool is_tsg)
                                         NVGPU_CHANNEL_FIFO_ERROR_IDLE_TIMEOUT);
                                 gk20a_channel_put(ch);
                         }
-                        mutex_unlock(&tsg->ch_list_lock);
+                        up_read(&tsg->ch_list_lock);
                         gk20a_fifo_recover_tsg(g, id, true);
                 } else {
                         struct channel_gk20a *ch = &g->fifo.channel[id];
@@ -2797,7 +2797,7 @@ static u32 *gk20a_runlist_construct_locked(struct fifo_gk20a *f,
                 count++;
                 (*entries_left)--;
 
-                mutex_lock(&tsg->ch_list_lock);
+                down_read(&tsg->ch_list_lock);
                 /* add runnable channels bound to this TSG */
                 list_for_each_entry(ch, &tsg->ch_list, ch_entry) {
                         if (!test_bit(ch->hw_chid,
@@ -2805,7 +2805,7 @@ static u32 *gk20a_runlist_construct_locked(struct fifo_gk20a *f,
                                 continue;
 
                         if (!(*entries_left)) {
-                                mutex_unlock(&tsg->ch_list_lock);
+                                up_read(&tsg->ch_list_lock);
                                 return NULL;
                         }
 
@@ -2819,7 +2819,7 @@ static u32 *gk20a_runlist_construct_locked(struct fifo_gk20a *f,
                         runlist_entry += runlist_entry_words;
                         (*entries_left)--;
                 }
-                mutex_unlock(&tsg->ch_list_lock);
+                up_read(&tsg->ch_list_lock);
         }
 
         /* append entries from higher level if this level is empty */
diff --git a/drivers/gpu/nvgpu/gk20a/tsg_gk20a.c b/drivers/gpu/nvgpu/gk20a/tsg_gk20a.c
index 0541f430..8e6f763a 100644
--- a/drivers/gpu/nvgpu/gk20a/tsg_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/tsg_gk20a.c
@@ -43,11 +43,11 @@ int gk20a_enable_tsg(struct tsg_gk20a *tsg)
         struct gk20a *g = tsg->g;
         struct channel_gk20a *ch;
 
-        mutex_lock(&tsg->ch_list_lock);
+        down_read(&tsg->ch_list_lock);
         list_for_each_entry(ch, &tsg->ch_list, ch_entry) {
                 g->ops.fifo.enable_channel(ch);
         }
-        mutex_unlock(&tsg->ch_list_lock);
+        up_read(&tsg->ch_list_lock);
 
         return 0;
 }
@@ -57,11 +57,11 @@ int gk20a_disable_tsg(struct tsg_gk20a *tsg)
         struct gk20a *g = tsg->g;
         struct channel_gk20a *ch;
 
-        mutex_lock(&tsg->ch_list_lock);
+        down_read(&tsg->ch_list_lock);
         list_for_each_entry(ch, &tsg->ch_list, ch_entry) {
                 g->ops.fifo.disable_channel(ch);
         }
-        mutex_unlock(&tsg->ch_list_lock);
+        up_read(&tsg->ch_list_lock);
 
         return 0;
 }
@@ -126,9 +126,9 @@ int gk20a_tsg_bind_channel(struct tsg_gk20a *tsg,
                 return -EINVAL;
         }
 
-        mutex_lock(&tsg->ch_list_lock);
+        down_write(&tsg->ch_list_lock);
         list_add_tail(&ch->ch_entry, &tsg->ch_list);
-        mutex_unlock(&tsg->ch_list_lock);
+        up_write(&tsg->ch_list_lock);
 
         kref_get(&tsg->refcount);
 
@@ -144,9 +144,9 @@ int gk20a_tsg_unbind_channel(struct channel_gk20a *ch)
         struct fifo_gk20a *f = &ch->g->fifo;
         struct tsg_gk20a *tsg = &f->tsg[ch->tsgid];
 
-        mutex_lock(&tsg->ch_list_lock);
+        down_write(&tsg->ch_list_lock);
         list_del_init(&ch->ch_entry);
-        mutex_unlock(&tsg->ch_list_lock);
+        up_write(&tsg->ch_list_lock);
 
         kref_put(&tsg->refcount, gk20a_tsg_release);
 
@@ -168,7 +168,7 @@ int gk20a_init_tsg_support(struct gk20a *g, u32 tsgid)
         tsg->tsgid = tsgid;
 
         INIT_LIST_HEAD(&tsg->ch_list);
-        mutex_init(&tsg->ch_list_lock);
+        init_rwsem(&tsg->ch_list_lock);
 
         INIT_LIST_HEAD(&tsg->event_id_list);
         mutex_init(&tsg->event_id_list_lock);
diff --git a/drivers/gpu/nvgpu/gk20a/tsg_gk20a.h b/drivers/gpu/nvgpu/gk20a/tsg_gk20a.h
index dbfb068b..8509398c 100644
--- a/drivers/gpu/nvgpu/gk20a/tsg_gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/tsg_gk20a.h
@@ -41,7 +41,7 @@ struct tsg_gk20a {
 
         struct list_head ch_list;
         int num_active_channels;
-        struct mutex ch_list_lock;
+        struct rw_semaphore ch_list_lock;
 
         unsigned int timeslice_us;
         unsigned int timeslice_timeout;
diff --git a/drivers/gpu/nvgpu/vgpu/fifo_vgpu.c b/drivers/gpu/nvgpu/vgpu/fifo_vgpu.c
index c3669990..5ffc6a00 100644
--- a/drivers/gpu/nvgpu/vgpu/fifo_vgpu.c
+++ b/drivers/gpu/nvgpu/vgpu/fifo_vgpu.c
@@ -651,7 +651,7 @@ static int vgpu_fifo_force_reset_ch(struct channel_gk20a *ch,
         if (gk20a_is_channel_marked_as_tsg(ch)) {
                 tsg = &g->fifo.tsg[ch->tsgid];
 
-                mutex_lock(&tsg->ch_list_lock);
+                down_read(&tsg->ch_list_lock);
 
                 list_for_each_entry(ch_tsg, &tsg->ch_list, ch_entry) {
                         if (gk20a_channel_get(ch_tsg)) {
@@ -661,7 +661,7 @@ static int vgpu_fifo_force_reset_ch(struct channel_gk20a *ch,
                         }
                 }
 
-                mutex_unlock(&tsg->ch_list_lock);
+                up_read(&tsg->ch_list_lock);
         } else {
                 gk20a_set_error_notifier(ch, err_code);
                 ch->has_timedout = true;