PCI: endpoint: pci-ep-msi: Make embedded doorbell IRQ exclusive

Embedded doorbells may use the same virq for several messages. This does
not mean the IRQ itself should be shared. Consumers only need to request
each distinct virq once, as vNTB and pci-epf-test already do.

IRQF_SHARED would let different EPFs register handlers for the same IRQ.
The embedded doorbell interface cannot tell which EPF a write targets,
so every handler would handle it.

Only the first EPF can allocate doorbells today, so this cannot happen
yet. Drop IRQF_SHARED before extending the embedded backend to non-first
EPFs. A second request for the same IRQ will then fail with -EBUSY
instead of attaching another handler.

Signed-off-by: Koichiro Den <den@valinux.co.jp>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260728172306.2751813-3-den@valinux.co.jp

0 files changed, 0 insertions, 0 deletions