drm/i915: Remove locking from i915_gem_object_prepare_read/write

Execbuffer submission will perform its own WW locking, and we
cannot rely on the implicit lock there.

This also makes it clear that the GVT code will get a lockdep splat when
multiple batchbuffer shadows need to be performed in the same instance,
fix that up.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200819140904.1708856-7-maarten.lankhorst@linux.intel.com
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_domain.c b/drivers/gpu/drm/i915/gem/i915_gem_domain.c
index c0acfc97fae305ff30b26e07b4c76c1c6e6fbb43..8ebceebd11b090b3902615cf6b554bd28c9fbd97 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_domain.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_domain.c
@@ -576,19 +576,17 @@ int i915_gem_object_prepare_read(struct drm_i915_gem_object *obj,
        if (!i915_gem_object_has_struct_page(obj))
                return -ENODEV;
 
-       ret = i915_gem_object_lock_interruptible(obj, NULL);
-       if (ret)
-               return ret;
+       assert_object_held(obj);
 
        ret = i915_gem_object_wait(obj,
                                   I915_WAIT_INTERRUPTIBLE,
                                   MAX_SCHEDULE_TIMEOUT);
        if (ret)
-               goto err_unlock;
+               return ret;
 
        ret = i915_gem_object_pin_pages(obj);
        if (ret)
-               goto err_unlock;
+               return ret;
 
        if (obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_READ ||
            !static_cpu_has(X86_FEATURE_CLFLUSH)) {
@@ -616,8 +614,6 @@ out:
 
 err_unpin:
        i915_gem_object_unpin_pages(obj);
-err_unlock:
-       i915_gem_object_unlock(obj);
        return ret;
 }
 
@@ -630,20 +626,18 @@ int i915_gem_object_prepare_write(struct drm_i915_gem_object *obj,
        if (!i915_gem_object_has_struct_page(obj))
                return -ENODEV;
 
-       ret = i915_gem_object_lock_interruptible(obj, NULL);
-       if (ret)
-               return ret;
+       assert_object_held(obj);
 
        ret = i915_gem_object_wait(obj,
                                   I915_WAIT_INTERRUPTIBLE |
                                   I915_WAIT_ALL,
                                   MAX_SCHEDULE_TIMEOUT);
        if (ret)
-               goto err_unlock;
+               return ret;
 
        ret = i915_gem_object_pin_pages(obj);
        if (ret)
-               goto err_unlock;
+               return ret;
 
        if (obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_WRITE ||
            !static_cpu_has(X86_FEATURE_CLFLUSH)) {
@@ -680,7 +674,5 @@ out:
 
 err_unpin:
        i915_gem_object_unpin_pages(obj);
-err_unlock:
-       i915_gem_object_unlock(obj);
        return ret;
 }

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
index 51395a0ceb159875e8a8332f02104c52bc62ccf0..ac2001f10b61aa8848d775be8d12e0cf8c04d41f 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -991,11 +991,14 @@ static void reloc_cache_reset(struct reloc_cache *cache)
 
        vaddr = unmask_page(cache->vaddr);
        if (cache->vaddr & KMAP) {
+               struct drm_i915_gem_object *obj =
+                       (struct drm_i915_gem_object *)cache->node.mm;
                if (cache->vaddr & CLFLUSH_AFTER)
                        mb();
 
                kunmap_atomic(vaddr);
-               i915_gem_object_finish_access((struct drm_i915_gem_object *)cache->node.mm);
+               i915_gem_object_finish_access(obj);
+               i915_gem_object_unlock(obj);
        } else {
                struct i915_ggtt *ggtt = cache_to_ggtt(cache);
 
@@ -1031,10 +1034,16 @@ static void *reloc_kmap(struct drm_i915_gem_object *obj,
                unsigned int flushes;
                int err;
 
-               err = i915_gem_object_prepare_write(obj, &flushes);
+               err = i915_gem_object_lock_interruptible(obj, NULL);
                if (err)
                        return ERR_PTR(err);
 
+               err = i915_gem_object_prepare_write(obj, &flushes);
+               if (err) {
+                       i915_gem_object_unlock(obj);
+                       return ERR_PTR(err);
+               }
+
                BUILD_BUG_ON(KMAP & CLFLUSH_FLAGS);
                BUILD_BUG_ON((KMAP | CLFLUSH_FLAGS) & PAGE_MASK);
 

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
index 488459143366452ecd1f07b7c2389a80eab1361d..45d79d75e73a2f82a8e51be5589f07b899a9d79a 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
@@ -432,7 +432,6 @@ static inline void
 i915_gem_object_finish_access(struct drm_i915_gem_object *obj)
 {
        i915_gem_object_unpin_pages(obj);
-       i915_gem_object_unlock(obj);
 }
 
 static inline struct intel_engine_cs *

diff --git a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
index 68c3631f3746cc0219a469ae4126a981f2802a1f..5daf4a2be422a598fd80d28d1fc43f4d269f3a87 100644 (file)
--- a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
+++ b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
@@ -964,9 +964,10 @@ __cpu_check_shmem(struct drm_i915_gem_object *obj, u32 dword, u32 val)
        unsigned long n;
        int err;
 
+       i915_gem_object_lock(obj, NULL);
        err = i915_gem_object_prepare_read(obj, &needs_flush);
        if (err)
-               return err;
+               goto err_unlock;
 
        for (n = 0; n < obj->base.size >> PAGE_SHIFT; ++n) {
                u32 *ptr = kmap_atomic(i915_gem_object_get_page(obj, n));
@@ -986,6 +987,8 @@ __cpu_check_shmem(struct drm_i915_gem_object *obj, u32 dword, u32 val)
        }
 
        i915_gem_object_finish_access(obj);
+err_unlock:
+       i915_gem_object_unlock(obj);
 
        return err;
 }

diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c
index 1de2959b153c5903a4df3af2b1f624e95f52490a..dcdfc396f2f847da4d344650b1d2698cb7e57cde 100644 (file)
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c
@@ -27,9 +27,10 @@ static int cpu_set(struct context *ctx, unsigned long offset, u32 v)
        u32 *cpu;
        int err;
 
+       i915_gem_object_lock(ctx->obj, NULL);
        err = i915_gem_object_prepare_write(ctx->obj, &needs_clflush);
        if (err)
-               return err;
+               goto out;
 
        page = i915_gem_object_get_page(ctx->obj, offset >> PAGE_SHIFT);
        map = kmap_atomic(page);
@@ -46,7 +47,9 @@ static int cpu_set(struct context *ctx, unsigned long offset, u32 v)
        kunmap_atomic(map);
        i915_gem_object_finish_access(ctx->obj);
 
-       return 0;
+out:
+       i915_gem_object_unlock(ctx->obj);
+       return err;
 }
 
 static int cpu_get(struct context *ctx, unsigned long offset, u32 *v)
@@ -57,9 +60,10 @@ static int cpu_get(struct context *ctx, unsigned long offset, u32 *v)
        u32 *cpu;
        int err;
 
+       i915_gem_object_lock(ctx->obj, NULL);
        err = i915_gem_object_prepare_read(ctx->obj, &needs_clflush);
        if (err)
-               return err;
+               goto out;
 
        page = i915_gem_object_get_page(ctx->obj, offset >> PAGE_SHIFT);
        map = kmap_atomic(page);
@@ -73,7 +77,9 @@ static int cpu_get(struct context *ctx, unsigned long offset, u32 *v)
        kunmap_atomic(map);
        i915_gem_object_finish_access(ctx->obj);
 
-       return 0;
+out:
+       i915_gem_object_unlock(ctx->obj);
+       return err;
 }
 
 static int gtt_set(struct context *ctx, unsigned long offset, u32 v)

diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
index 52af9a52b7437c561f104814ab6981bed3dbe130..9160a335c684c915f7834ab9938c055b1fbd406e 100644 (file)
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
@@ -461,9 +461,10 @@ static int cpu_fill(struct drm_i915_gem_object *obj, u32 value)
        unsigned int n, m, need_flush;
        int err;
 
+       i915_gem_object_lock(obj, NULL);
        err = i915_gem_object_prepare_write(obj, &need_flush);
        if (err)
-               return err;
+               goto out;
 
        for (n = 0; n < real_page_count(obj); n++) {
                u32 *map;
@@ -479,7 +480,9 @@ static int cpu_fill(struct drm_i915_gem_object *obj, u32 value)
        i915_gem_object_finish_access(obj);
        obj->read_domains = I915_GEM_DOMAIN_GTT | I915_GEM_DOMAIN_CPU;
        obj->write_domain = 0;
-       return 0;
+out:
+       i915_gem_object_unlock(obj);
+       return err;
 }
 
 static noinline int cpu_check(struct drm_i915_gem_object *obj,
@@ -488,9 +491,10 @@ static noinline int cpu_check(struct drm_i915_gem_object *obj,
        unsigned int n, m, needs_flush;
        int err;
 
+       i915_gem_object_lock(obj, NULL);
        err = i915_gem_object_prepare_read(obj, &needs_flush);
        if (err)
-               return err;
+               goto out_unlock;
 
        for (n = 0; n < real_page_count(obj); n++) {
                u32 *map;
@@ -527,6 +531,8 @@ out_unmap:
        }
 
        i915_gem_object_finish_access(obj);
+out_unlock:
+       i915_gem_object_unlock(obj);
        return err;
 }
 

diff --git a/drivers/gpu/drm/i915/gvt/cmd_parser.c b/drivers/gpu/drm/i915/gvt/cmd_parser.c
index 943c8d2327035c41c2b4f8dc62cea2c3f0ac26fa..d0a599b51bfedfacbb0b9061f3a68c8546726f24 100644 (file)
--- a/drivers/gpu/drm/i915/gvt/cmd_parser.c
+++ b/drivers/gpu/drm/i915/gvt/cmd_parser.c
@@ -1923,6 +1923,7 @@ static int perform_bb_shadow(struct parser_exec_state *s)
        if (ret)
                goto err_unmap;
 
+       i915_gem_object_unlock(bb->obj);
        INIT_LIST_HEAD(&bb->list);
        list_add(&bb->list, &s->workload->shadow_bb);
 

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 4bc8fdb94019eefff96b14f7bf9432822b0fb354..55158e487a7f4dc6a009696044a481faf2b6cc9a 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -335,12 +335,20 @@ i915_gem_shmem_pread(struct drm_i915_gem_object *obj,
        u64 remain;
        int ret;
 
-       ret = i915_gem_object_prepare_read(obj, &needs_clflush);
+       ret = i915_gem_object_lock_interruptible(obj, NULL);
        if (ret)
                return ret;
 
+       ret = i915_gem_object_prepare_read(obj, &needs_clflush);
+       if (ret) {
+               i915_gem_object_unlock(obj);
+               return ret;
+       }
+
        fence = i915_gem_object_lock_fence(obj);
        i915_gem_object_finish_access(obj);
+       i915_gem_object_unlock(obj);
+
        if (!fence)
                return -ENOMEM;
 
@@ -734,12 +742,20 @@ i915_gem_shmem_pwrite(struct drm_i915_gem_object *obj,
        u64 remain;
        int ret;
 
-       ret = i915_gem_object_prepare_write(obj, &needs_clflush);
+       ret = i915_gem_object_lock_interruptible(obj, NULL);
        if (ret)
                return ret;
 
+       ret = i915_gem_object_prepare_write(obj, &needs_clflush);
+       if (ret) {
+               i915_gem_object_unlock(obj);
+               return ret;
+       }
+
        fence = i915_gem_object_lock_fence(obj);
        i915_gem_object_finish_access(obj);
+       i915_gem_object_unlock(obj);
+
        if (!fence)
                return -ENOMEM;