[PATCH net-next 07/10] sfc: Explain why efx_mcdi_exit_assertion() ignores result of efx_mcdi_rpc()

Ben Hutchings
2012-07-17T18:07:13Z

Fix CID 113952 in Coverity report on Linux.

This is the one instance where we don't, and shouldn't, check the
return code from efx_mcdi_rpc(). It wasn't immediately obvious to me
why we didn't, so I think an explanation is in order.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
---
drivers/net/ethernet/sfc/mcdi.c | 11 ++++++++---
1 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/sfc/mcdi.c b/drivers/net/ethernet/sfc/mcdi.c
index 17b6463..fc5e7bb 100644
--- a/drivers/net/ethernet/sfc/mcdi.c
+++ b/drivers/net/ethernet/sfc/mcdi.c
@@ -1001,12 +1001,17 @@ static void efx_mcdi_exit_assertion(struct efx_nic *efx)
{
u8 inbuf[MC_CMD_REBOOT_IN_LEN];

- /* Atomically reboot the mcfw out of the assertion handler */
+ /* If the MC is running debug firmware, it might now be
+ * waiting for a debugger to attach, but we just want it to
+ * reboot. We set a flag that makes the command a no-op if it
+ * has already done so. We don't know what return code to
+ * expect (0 or -EIO), so ignore it.
+ */
BUILD_BUG_ON(MC_CMD_REBOOT_OUT_LEN != 0);
MCDI_SET_DWORD(inbuf, REBOOT_IN_FLAGS,
MC_CMD_REBOOT_FLAGS_AFTER_ASSERTION);
- efx_mcdi_rpc(efx, MC_CMD_REBOOT, inbuf, MC_CMD_REBOOT_IN_LEN,
- NULL, 0, NULL);
+ (void) efx_mcdi_rpc(efx, MC_CMD_REBOOT, inbuf, MC_CMD_REBOOT_IN_LEN,
+ NULL, 0, NULL);
}

int efx_mcdi_handle_assertion(struct efx_nic *efx)