drm/i915: Switch context id allocation directly to xarray

IDR internally uses xarray so we can use it directly which simplifies our
code by removing the need to do external locking.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191224095920.2386297-1-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index dc90b044a2179454bedc96e7d9d0aa986b43dae2..f746bb53f18e068ba7c86ecc40a41fdee758e8c1 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -760,12 +760,6 @@ void i915_gem_driver_release__contexts(struct drm_i915_private *i915)
        flush_work(&i915->gem.contexts.free_work);
 }
 
-static int context_idr_cleanup(int id, void *p, void *data)
-{
-       context_close(p);
-       return 0;
-}
-
 static int vm_idr_cleanup(int id, void *p, void *data)
 {
        i915_vm_put(p);
@@ -773,7 +767,8 @@ static int vm_idr_cleanup(int id, void *p, void *data)
 }
 
 static int gem_context_register(struct i915_gem_context *ctx,
-                               struct drm_i915_file_private *fpriv)
+                               struct drm_i915_file_private *fpriv,
+                               u32 *id)
 {
        struct i915_address_space *vm;
        int ret;
@@ -791,14 +786,10 @@ static int gem_context_register(struct i915_gem_context *ctx,
                 current->comm, pid_nr(ctx->pid));
 
        /* And finally expose ourselves to userspace via the idr */
-       mutex_lock(&fpriv->context_idr_lock);
-       ret = idr_alloc(&fpriv->context_idr, ctx, 0, 0, GFP_KERNEL);
-       mutex_unlock(&fpriv->context_idr_lock);
-       if (ret >= 0)
-               goto out;
+       ret = xa_alloc(&fpriv->context_xa, id, ctx, xa_limit_32b, GFP_KERNEL);
+       if (ret)
+               put_pid(fetch_and_zero(&ctx->pid));
 
-       put_pid(fetch_and_zero(&ctx->pid));
-out:
        return ret;
 }
 
@@ -808,11 +799,11 @@ int i915_gem_context_open(struct drm_i915_private *i915,
        struct drm_i915_file_private *file_priv = file->driver_priv;
        struct i915_gem_context *ctx;
        int err;
+       u32 id;
 
-       mutex_init(&file_priv->context_idr_lock);
-       mutex_init(&file_priv->vm_idr_lock);
+       xa_init_flags(&file_priv->context_xa, XA_FLAGS_ALLOC);
 
-       idr_init(&file_priv->context_idr);
+       mutex_init(&file_priv->vm_idr_lock);
        idr_init_base(&file_priv->vm_idr, 1);
 
        ctx = i915_gem_create_context(i915, 0);
@@ -821,21 +812,19 @@ int i915_gem_context_open(struct drm_i915_private *i915,
                goto err;
        }
 
-       err = gem_context_register(ctx, file_priv);
+       err = gem_context_register(ctx, file_priv, &id);
        if (err < 0)
                goto err_ctx;
 
-       GEM_BUG_ON(err > 0);
-
+       GEM_BUG_ON(id);
        return 0;
 
 err_ctx:
        context_close(ctx);
 err:
        idr_destroy(&file_priv->vm_idr);
-       idr_destroy(&file_priv->context_idr);
+       xa_destroy(&file_priv->context_xa);
        mutex_destroy(&file_priv->vm_idr_lock);
-       mutex_destroy(&file_priv->context_idr_lock);
        return err;
 }
 
@@ -843,10 +832,12 @@ void i915_gem_context_close(struct drm_file *file)
 {
        struct drm_i915_file_private *file_priv = file->driver_priv;
        struct drm_i915_private *i915 = file_priv->dev_priv;
+       struct i915_gem_context *ctx;
+       unsigned long idx;
 
-       idr_for_each(&file_priv->context_idr, context_idr_cleanup, NULL);
-       idr_destroy(&file_priv->context_idr);
-       mutex_destroy(&file_priv->context_idr_lock);
+       xa_for_each(&file_priv->context_xa, idx, ctx)
+               context_close(ctx);
+       xa_destroy(&file_priv->context_xa);
 
        idr_for_each(&file_priv->vm_idr, vm_idr_cleanup, NULL);
        idr_destroy(&file_priv->vm_idr);
@@ -2187,6 +2178,7 @@ int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
        struct drm_i915_gem_context_create_ext *args = data;
        struct create_ext ext_data;
        int ret;
+       u32 id;
 
        if (!DRIVER_CAPS(i915)->has_logical_contexts)
                return -ENODEV;
@@ -2218,11 +2210,11 @@ int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
                        goto err_ctx;
        }
 
-       ret = gem_context_register(ext_data.ctx, ext_data.fpriv);
+       ret = gem_context_register(ext_data.ctx, ext_data.fpriv, &id);
        if (ret < 0)
                goto err_ctx;
 
-       args->ctx_id = ret;
+       args->ctx_id = id;
        DRM_DEBUG("HW context %d created\n", args->ctx_id);
 
        return 0;
@@ -2245,11 +2237,7 @@ int i915_gem_context_destroy_ioctl(struct drm_device *dev, void *data,
        if (!args->ctx_id)
                return -ENOENT;
 
-       if (mutex_lock_interruptible(&file_priv->context_idr_lock))
-               return -EINTR;
-
-       ctx = idr_remove(&file_priv->context_idr, args->ctx_id);
-       mutex_unlock(&file_priv->context_idr_lock);
+       ctx = xa_erase(&file_priv->context_xa, args->ctx_id);
        if (!ctx)
                return -ENOENT;
 

diff --git a/drivers/gpu/drm/i915/gem/selftests/mock_context.c b/drivers/gpu/drm/i915/gem/selftests/mock_context.c
index 7d7e13dc2fdfe8b64a873c6c153b5954649c50f5..384143aa77769abe7513494b3b08c93b92c3f13a 100644 (file)
--- a/drivers/gpu/drm/i915/gem/selftests/mock_context.c
+++ b/drivers/gpu/drm/i915/gem/selftests/mock_context.c
@@ -77,12 +77,13 @@ live_context(struct drm_i915_private *i915, struct file *file)
 {
        struct i915_gem_context *ctx;
        int err;
+       u32 id;
 
        ctx = i915_gem_create_context(i915, 0);
        if (IS_ERR(ctx))
                return ctx;
 
-       err = gem_context_register(ctx, to_drm_file(file)->driver_priv);
+       err = gem_context_register(ctx, to_drm_file(file)->driver_priv, &id);
        if (err < 0)
                goto err_ctx;
 

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index d05a968227f7370b9363c72dabca5419c78c2f7c..b7f122dccdcadfcb744c8335afa934590dcec3ef 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -46,6 +46,7 @@
 #include <linux/dma-resv.h>
 #include <linux/shmem_fs.h>
 #include <linux/stackdepot.h>
+#include <linux/xarray.h>
 
 #include <drm/intel-gtt.h>
 #include <drm/drm_legacy.h> /* for struct drm_dma_handle */
@@ -201,8 +202,7 @@ struct drm_i915_file_private {
                struct list_head request_list;
        } mm;
 
-       struct idr context_idr;
-       struct mutex context_idr_lock; /* guards context_idr */
+       struct xarray context_xa;
 
        struct idr vm_idr;
        struct mutex vm_idr_lock; /* guards vm_idr */
@@ -1889,7 +1889,7 @@ struct dma_buf *i915_gem_prime_export(struct drm_gem_object *gem_obj, int flags)
 static inline struct i915_gem_context *
 __i915_gem_context_lookup_rcu(struct drm_i915_file_private *file_priv, u32 id)
 {
-       return idr_find(&file_priv->context_idr, id);
+       return xa_load(&file_priv->context_xa, id);
 }
 
 static inline struct i915_gem_context *