[PATCH] virtio_pci_modern: Use GFP_ATOMIC with spin_lock_irqsave held in virtqueue_exec_admin_cmd()

[Jinhui Guo]

virtqueue_exec_admin_cmd() holds admin_vq->lock with spin_lock_irqsave(),
which disables interrupts.  Using GFP_KERNEL inside this critical section
is unsafe because kmalloc() may sleep, leading to potential deadlocks or
scheduling violations.

Switch to GFP_ATOMIC to ensure the allocation is non-blocking.

Fixes: 4c3b54af907e ("virtio_pci_modern: use completion instead of busy loop to 
wait on admin cmd result")
Cc: sta...@vger.kernel.org
Signed-off-by: Jinhui Guo <guojinhui.l...@bytedance.com>
---
 drivers/virtio/virtio_pci_modern.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/virtio/virtio_pci_modern.c 
b/drivers/virtio/virtio_pci_modern.c
index 6d8ae2a6a8ca..db8e4f88b749 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -101,7 +101,7 @@ static int virtqueue_exec_admin_cmd(struct 
virtio_pci_admin_vq *admin_vq,
                return -EIO;
 
        spin_lock_irqsave(&admin_vq->lock, flags);
-       ret = virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, GFP_KERNEL);
+       ret = virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, GFP_ATOMIC);
        if (ret < 0) {
                if (ret == -ENOSPC) {
                        spin_unlock_irqrestore(&admin_vq->lock, flags);
-- 
2.20.1