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drm/i915: Use RCU for unlocked vm_idr lookup

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Since i915_address_space is now RCU protected, we can do the vm_idr lookup
without taking the vm_idr_mutex, just with the rcu_read_lock() instead.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190830180325.7755-1-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson 2019-08-30 19:03:25 +01:00
parent c1d143dd2a
commit aabbe344dc
1 changed files with 4 additions and 7 deletions
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11
drivers/gpu/drm/i915/gem/i915_gem_context.c
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@ -1057,14 +1057,11 @@ static int set_ppgtt(struct drm_i915_file_private *file_priv,
if (upper_32_bits(args->value))
return -ENOENT;
err = mutex_lock_interruptible(&file_priv->vm_idr_lock);
if (err)
return err;
rcu_read_lock();
vm = idr_find(&file_priv->vm_idr, args->value);
if (vm)
i915_vm_get(vm);
mutex_unlock(&file_priv->vm_idr_lock);
if (vm && !kref_get_unless_zero(&vm->ref))
vm = NULL;
rcu_read_unlock();
if (!vm)
return -ENOENT;