This is a note to let you know that I've just added the patch titled sfc: Fix timekeeping in efx_mcdi_poll() to the 3.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: sfc-fix-timekeeping-in-efx_mcdi_poll.patch and it can be found in the queue-3.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 6967d4846947cf5dfe8cca164c12d80d35d94367 Mon Sep 17 00:00:00 2001 From: Ben Hutchings <bhutchings@xxxxxxxxxxxxxx> Date: Sat, 1 Dec 2012 02:21:17 +0000 Subject: sfc: Fix timekeeping in efx_mcdi_poll() From: Ben Hutchings <bhutchings@xxxxxxxxxxxxxx> [ 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@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/ethernet/sfc/mcdi.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) --- 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_ 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 * 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 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_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(str 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. Patches currently in stable-queue which might be from bhutchings@xxxxxxxxxxxxxx are queue-3.4/sfc-really-disable-flow-control-while-flushing.patch queue-3.4/sfc-disable-vf-queues-during-register-self-test.patch queue-3.4/sfc-correctly-initialise-reset_method-in-siena_test_chip.patch queue-3.4/sfc-do-not-attempt-to-flush-queues-if-dma-is-disabled.patch queue-3.4/sfc-avoid-generating-over-length-mc_cmd_flush_rx_queues-request.patch queue-3.4/sfc-work-around-flush-timeout-when-flushes-have-completed.patch queue-3.4/sfc-add-parentheses-around-use-of-bitfield-macro-arguments.patch queue-3.4/sfc-fix-mcdi-structure-field-lookup.patch queue-3.4/sfc-properly-sync-rx-dma-buffer-when-it-is-not-the-last-in-the-page.patch queue-3.4/sfc-only-use-tx-push-if-a-single-descriptor-is-to-be-written.patch queue-3.4/sfc-fix-efx_rx_buf_offset-in-the-presence-of-swiotlb.patch queue-3.4/sfc-lock-tx-queues-when-calling-netif_device_detach.patch queue-3.4/sfc-convert-firmware-subtypes-to-native-byte-order-in-efx_mcdi_get_board_cfg.patch queue-3.4/sfc-fix-timekeeping-in-efx_mcdi_poll.patch queue-3.4/sfc-disable-soft-interrupt-handling-during-efx_device_detach_sync.patch queue-3.4/sfc-detach-net-device-when-stopping-queues-for-reconfiguration.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html