diff options
| author | Ben Hutchings <bhutchings@solarflare.com> | 2012-12-01 02:21:17 +0000 |
|---|---|---|
| committer | Ben Hutchings <bhutchings@solarflare.com> | 2012-12-01 02:37:36 +0000 |
| commit | ebf98e797b4e26ad52ace1511a0b503ee60a6cd4 (patch) | |
| tree | f1857b52b3eced0485c059dac8a4882216cbf7a0 /drivers | |
| parent | c2f3b8e3a44b6fe9e36704e30157ebe1a88c08b1 (diff) | |
sfc: Fix timekeeping in efx_mcdi_poll()
efx_mcdi_poll() uses get_seconds() to read the current time and to
implement a polling timeout. The use of this function was chosen
partly because it could easily be replaced in a co-sim environment
with a macro that read the simulated time.
Unfortunately the real get_seconds() returns the system time (real
time) which is subject to adjustment by e.g. ntpd. If the system time
is adjusted forward during a polled MCDI operation, the effective
timeout can be shorter than the intended 10 seconds, resulting in a
spurious failure. It is also possible for a backward adjustment to
delay detection of a areal failure.
Use jiffies instead, and change MCDI_RPC_TIMEOUT to be denominated in
jiffies. Also correct rounding of the timeout: check time > finish
(or rather time_after(time, finish)) and not time >= finish.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/net/ethernet/sfc/mcdi.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/drivers/net/ethernet/sfc/mcdi.c b/drivers/net/ethernet/sfc/mcdi.c index 3ef71a0f99a8..0095ce95150b 100644 --- a/drivers/net/ethernet/sfc/mcdi.c +++ b/drivers/net/ethernet/sfc/mcdi.c @@ -22,7 +22,7 @@ ************************************************************************** */ -#define MCDI_RPC_TIMEOUT 10 /*seconds */ +#define MCDI_RPC_TIMEOUT (10 * HZ) #define MCDI_PDU(efx) \ (efx_port_num(efx) ? MC_SMEM_P1_PDU_OFST : MC_SMEM_P0_PDU_OFST) @@ -120,7 +120,7 @@ static void efx_mcdi_copyout(struct efx_nic *efx, u8 *outbuf, size_t outlen) static int efx_mcdi_poll(struct efx_nic *efx) { struct efx_mcdi_iface *mcdi = efx_mcdi(efx); - unsigned int time, finish; + unsigned long time, finish; unsigned int respseq, respcmd, error; unsigned int pdu = FR_CZ_MC_TREG_SMEM + MCDI_PDU(efx); unsigned int rc, spins; @@ -136,7 +136,7 @@ static int efx_mcdi_poll(struct efx_nic *efx) * and poll once a jiffy (approximately) */ spins = TICK_USEC; - finish = get_seconds() + MCDI_RPC_TIMEOUT; + finish = jiffies + MCDI_RPC_TIMEOUT; while (1) { if (spins != 0) { @@ -146,7 +146,7 @@ static int efx_mcdi_poll(struct efx_nic *efx) schedule_timeout_uninterruptible(1); } - time = get_seconds(); + time = jiffies; rmb(); efx_readd(efx, ®, pdu); @@ -158,7 +158,7 @@ static int efx_mcdi_poll(struct efx_nic *efx) EFX_DWORD_FIELD(reg, MCDI_HEADER_RESPONSE)) break; - if (time >= finish) + if (time_after(time, finish)) return -ETIMEDOUT; } @@ -257,7 +257,7 @@ static int efx_mcdi_await_completion(struct efx_nic *efx) if (wait_event_timeout( mcdi->wq, atomic_read(&mcdi->state) == MCDI_STATE_COMPLETED, - msecs_to_jiffies(MCDI_RPC_TIMEOUT * 1000)) == 0) + MCDI_RPC_TIMEOUT) == 0) return -ETIMEDOUT; /* Check if efx_mcdi_set_mode() switched us back to polled completions. |