[PATCH] use cond_resched() to replace udelay() when dump eeprom
From: Cho, Yu-Chen <hidden>
Date: 2014-05-12 07:14:07
Subsystem:
broadcom tg3 gigabit ethernet driver, networking drivers, the rest · Maintainers:
Pavan Chebbi, Michael Chan, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
The loop in tg3_nvram_exec_cmd() will give up after about 100 msec per command, it can loop for a long time. For some test case , if we try to dump eeprom from tg3 interface, what is UP but not running , NO-CARRIER (no cable), then the lock up occurs: [<ffffffffa01def4a>] tg3_nvram_exec_cmd+0x3a/0x60 [tg3] [<ffffffffa01e2982>] tg3_nvram_read+0x62/0x130 [tg3] [<ffffffffa01e2a62>] tg3_nvram_read_be32+0x12/0x30 [tg3] [<ffffffffa01e2b1d>] tg3_get_eeprom+0x9d/0x190 [tg3] [<ffffffff81494cc2>] ethtool_get_any_eeprom+0xe2/0x170 [<ffffffff81496108>] dev_ethtool+0xd58/0x1a60 [<ffffffff814a43fb>] dev_ioctl+0x1ab/0x560 [<ffffffff8147782d>] sock_do_ioctl+0x3d/0x50 [<ffffffff81477c78>] sock_ioctl+0x1e8/0x2c0 [<ffffffff81197cc4>] do_vfs_ioctl+0x2d4/0x4b0 [<ffffffff81197f20>] SyS_ioctl+0x80/0xa0 [<ffffffff81581a7d>] system_call_fastpath+0x1a/0x1f [<00007f6b6cbf4387>] 0x7f6b6cbf4386 Signed-off-by: Cho, Yu-Chen <redacted> --- drivers/net/ethernet/broadcom/tg3.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index e5d95c5..7dc8bb5 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c@@ -3232,7 +3232,9 @@ static int tg3_nvram_exec_cmd(struct tg3 *tp, u32 nvram_cmd) tw32(NVRAM_CMD, nvram_cmd); for (i = 0; i < NVRAM_CMD_TIMEOUT; i++) { - udelay(10); + + cond_resched(); + if (tr32(NVRAM_CMD) & NVRAM_CMD_DONE) { udelay(10); break;
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1.8.4.5