PCI: endpoint: pci-epf-vntb: Defer pci_epc_raise_irq() out of atomic context

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The NTB .peer_db_set() callback may be invoked from atomic context.
pci-epf-vntb currently calls pci_epc_raise_irq() directly, but
pci_epc_raise_irq() may sleep (it takes epc->lock).

Avoid sleeping in atomic context by coalescing doorbell bits into an
atomic64 pending mask and raising MSIs from a work item. Limit the
amount of work per run to avoid monopolizing the workqueue under a
doorbell storm.

Clear stale pending bits before enabling the work item and after disabling
it during cleanup. Also mask requested doorbells against the currently
valid doorbell mask before queueing work, and iterate the pending u64 with
__ffs64() so high doorbell bits are handled correctly.

Fixes: e35f56bb03 ("PCI: endpoint: Support NTB transfer between RC and EP")
Signed-off-by: Koichiro Den <den@valinux.co.jp>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260513024923.451765-3-den@valinux.co.jp

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Koichiro Den 2026-05-13 11:49:13 +09:00 • committed by Bjorn Helgaas

parent 6a7db4fcc6

commit 18355c1e98

1 changed files with 85 additions and 27 deletions

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drivers/pci/endpoint/functions/pci-epf-vntb.c

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