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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Karol Herbst <kherbst@redhat.com>,
        Ben Skeggs <bskeggs@redhat.com>
Subject: [PATCH 5.10 059/142] drm/nouveau/svm: fail NOUVEAU_SVM_INIT ioctl on unsupported devices
Date:   Tue,  2 Feb 2021 14:37:02 +0100
Message-Id: <20210202133000.153752372@linuxfoundation.org>
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From: Karol Herbst <kherbst@redhat.com>

commit dcd602cc5fe2803bf532d407cde24ba0b7808ff3 upstream.

Fixes a crash when trying to create a channel on e.g. Turing GPUs when
NOUVEAU_SVM_INIT was called before.

Fixes: eeaf06ac1a558 ("drm/nouveau/svm: initial support for shared virtual memory")
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/nouveau/nouveau_svm.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/gpu/drm/nouveau/nouveau_svm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_svm.c
@@ -315,6 +315,10 @@ nouveau_svmm_init(struct drm_device *dev
 	struct drm_nouveau_svm_init *args = data;
 	int ret;
 
+	/* We need to fail if svm is disabled */
+	if (!cli->drm->svm)
+		return -ENOSYS;
+
 	/* Allocate tracking for SVM-enabled VMM. */
 	if (!(svmm = kzalloc(sizeof(*svmm), GFP_KERNEL)))
 		return -ENOMEM;