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 3.0-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-3.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 4b98c03ffda282768c7dd09c35783fce1f8cd050 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>
[bwh: Backported to 3.0: adjust context]
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/sfc/mcdi.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
--- 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_
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-3.0/sfc-fix-siena-mac-statistics-on-big-endian-platforms.patch
queue-3.0/sfc-do-not-attempt-to-flush-queues-if-dma-is-disabled.patch
queue-3.0/sfc-fix-two-causes-of-flush-failure.patch
queue-3.0/sfc-properly-sync-rx-dma-buffer-when-it-is-not-the-last-in-the-page.patch
queue-3.0/sfc-only-use-tx-push-if-a-single-descriptor-is-to-be-written.patch
queue-3.0/sfc-fix-efx_rx_buf_offset-in-the-presence-of-swiotlb.patch
queue-3.0/sfc-lock-tx-queues-when-calling-netif_device_detach.patch
queue-3.0/sfc-convert-firmware-subtypes-to-native-byte-order-in-efx_mcdi_get_board_cfg.patch
queue-3.0/sfc-fix-timekeeping-in-efx_mcdi_poll.patch
queue-3.0/sfc-disable-soft-interrupt-handling-during-efx_device_detach_sync.patch
queue-3.0/sfc-fix-loop-condition-for-efx_filter_search-when-for_insert.patch
queue-3.0/sfc-detach-net-device-when-stopping-queues-for-reconfiguration.patch
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