[SRU][N][PATCH 1/2] vhost: return task creation error instead of NULL

[Magali Lemes]

From: Keith Busch <kbusch at kernel.org>

BugLink: https://bugs.launchpad.net/bugs/2109859

Lets callers distinguish why the vhost task creation failed. No one
currently cares why it failed, so no real runtime change from this
patch, but that will not be the case for long.

Signed-off-by: Keith Busch <kbusch at kernel.org>
Message-ID: <20250227230631.303431-2-kbusch at meta.com>
Reviewed-by: Mike Christie <michael.christie at oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini at redhat.com>
(cherry picked from commit cb380909ae3b1ebf14d6a455a4f92d7916d790cb)
Signed-off-by: Magali Lemes <magali.lemes at canonical.com>
---
 arch/x86/kvm/mmu/mmu.c | 2 +-
 drivers/vhost/vhost.c  | 2 +-
 kernel/vhost_task.c    | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 7dfa83b3292d9..d8e449c215a25 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -7299,7 +7299,7 @@ static void kvm_mmu_start_lpage_recovery(struct once *once)
 				      kvm_nx_huge_page_recovery_worker_kill,
 				      kvm, "kvm-nx-lpage-recovery");
 
-	if (!nx_thread)
+	if (IS_ERR(nx_thread))
 		return;
 
 	vhost_task_start(nx_thread);
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index a6bf56d0cabce..fd1ac1e2f5136 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -678,7 +678,7 @@ static struct vhost_worker *vhost_worker_create(struct vhost_dev *dev)
 
 	vtsk = vhost_task_create(vhost_run_work_list, vhost_worker_killed,
 				 worker, name);
-	if (!vtsk)
+	if (IS_ERR(vtsk))
 		goto free_worker;
 
 	mutex_init(&worker->mutex);
diff --git a/kernel/vhost_task.c b/kernel/vhost_task.c
index 8800f5acc0071..2ef2e1b800916 100644
--- a/kernel/vhost_task.c
+++ b/kernel/vhost_task.c
@@ -133,7 +133,7 @@ struct vhost_task *vhost_task_create(bool (*fn)(void *),
 
 	vtsk = kzalloc(sizeof(*vtsk), GFP_KERNEL);
 	if (!vtsk)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 	init_completion(&vtsk->exited);
 	mutex_init(&vtsk->exit_mutex);
 	vtsk->data = arg;
@@ -145,7 +145,7 @@ struct vhost_task *vhost_task_create(bool (*fn)(void *),
 	tsk = copy_process(NULL, 0, NUMA_NO_NODE, &args);
 	if (IS_ERR(tsk)) {
 		kfree(vtsk);
-		return NULL;
+		return ERR_PTR(PTR_ERR(tsk));
 	}
 
 	vtsk->task = tsk;
-- 
2.34.1