diff options
| author | Ben Hutchings <bhutchings@solarflare.com> | 2012-12-01 02:21:17 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-03-28 12:06:01 -0700 |
| commit | 16cec22e5099020edb0ba8b6ae8f1b011e2ec4d5 (patch) | |
| tree | 499ce5b037ca7e1b450f0a56abd7b1057056e4c8 | |
| parent | 376ed848f420a921325e9dc144c9cc7fa3829a38 (diff) | |
sfc: Fix timekeeping in efx_mcdi_poll()
[ Upstream commit ebf98e797b4e26ad52ace1511a0b503ee60a6cd4 ]
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>
[bwh: Backported to 3.0: adjust context]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/net/sfc/mcdi.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/drivers/net/sfc/mcdi.c b/drivers/net/sfc/mcdi.c index 85e070e9f04..c1000ce549e 100644 --- a/drivers/net/sfc/mcdi.c +++ b/drivers/net/sfc/mcdi.c @@ -30,7 +30,7 @@ #define REBOOT_FLAG_PORT0 0x3f8 #define REBOOT_FLAG_PORT1 0x3fc -#define MCDI_RPC_TIMEOUT 10 /*seconds */ +#define MCDI_RPC_TIMEOUT (10 * HZ) #define MCDI_PDU(efx) \ (efx_port_num(efx) ? CMD_PDU_PORT1 : CMD_PDU_PORT0) @@ -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; } @@ -250,7 +250,7 @@ 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. |