[PATCH] pch_dma: Fix channel locking
From: Alexander Stein
Date: Wed Jun 22 2011 - 11:05:40 EST
Fix for the following INFO message
=================================
[ INFO: inconsistent lock state ]
2.6.39+ #89
---------------------------------
inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage.
rs232/822 [HC1[1]:SC0[0]:HE0:SE1] takes:
(&(&pd_chan->lock)->rlock){?.....}, at: [<c123b9a1>] pdc_desc_get+0x16/0xab
{HARDIRQ-ON-W} state was registered at:
[<c104fe28>] mark_irqflags+0xbd/0x11a
[<c1050386>] __lock_acquire+0x501/0x6bb
[<c1050945>] lock_acquire+0x63/0x7b
[<c131c51d>] _raw_spin_lock_bh+0x43/0x51
[<c123bee4>] pd_alloc_chan_resources+0x92/0x11e
[<c123ad62>] dma_chan_get+0x9b/0x107
[<c123b2d1>] __dma_request_channel+0x61/0xdc
[<c11ba24b>] pch_request_dma+0x61/0x19e
[<c11bb3b8>] pch_uart_startup+0x16a/0x1a2
[<c11b8446>] uart_startup+0x87/0x147
[<c11b9183>] uart_open+0x117/0x13e
[<c11a5c7d>] tty_open+0x23c/0x34c
[<c1097705>] chrdev_open+0x140/0x15f
[<c10930a6>] __dentry_open.clone.14+0x14a/0x22b
[<c1093dfb>] nameidata_to_filp+0x36/0x40
[<c109f28b>] do_last+0x513/0x635
[<c109f4af>] path_openat+0x9c/0x2aa
[<c109f6e4>] do_filp_open+0x27/0x69
[<c1093f02>] do_sys_open+0xfd/0x184
[<c1093fad>] sys_open+0x24/0x2a
[<c131d58c>] sysenter_do_call+0x12/0x32
irq event stamp: 2522
hardirqs last enabled at (2521): [<c131ca3b>] _raw_spin_unlock_irqrestore+0x36/0x52
hardirqs last disabled at (2522): [<c131db27>] common_interrupt+0x27/0x34
softirqs last enabled at (2354): [<c102fa11>] __do_softirq+0x10a/0x11a
softirqs last disabled at (2299): [<c10041a4>] do_softirq+0x57/0xa4
other info that might help us debug this:
2 locks held by rs232/822:
#0: (&tty->atomic_write_lock){+.+.+.}, at: [<c11a4b7a>] tty_write_lock+0x14/0x3c
#1: (&port_lock_key){-.....}, at: [<c11bad72>] pch_uart_interrupt+0x17/0x1e9
stack backtrace:
Pid: 822, comm: rs232 Not tainted 2.6.39+ #89
Call Trace:
[<c1319f90>] ? printk+0x19/0x1b
[<c104f893>] print_usage_bug+0x184/0x18f
[<c104e5b1>] ? print_irq_inversion_bug+0x10e/0x10e
[<c104f943>] mark_lock_irq+0xa5/0x1f6
[<c104fc9c>] mark_lock+0x208/0x2d7
[<c104fdc0>] mark_irqflags+0x55/0x11a
[<c1050386>] __lock_acquire+0x501/0x6bb
[<c10042ee>] ? dump_trace+0x92/0xb6
[<c1050945>] lock_acquire+0x63/0x7b
[<c123b9a1>] ? pdc_desc_get+0x16/0xab
[<c131c2d0>] _raw_spin_lock+0x3e/0x4c
[<c123b9a1>] ? pdc_desc_get+0x16/0xab
[<c123b9a1>] pdc_desc_get+0x16/0xab
[<c10504d8>] ? __lock_acquire+0x653/0x6bb
[<c123bb2c>] pd_prep_slave_sg+0x7c/0x1cb
[<c1006c3f>] ? nommu_map_sg+0x6e/0x81
[<c11bace6>] dma_handle_tx+0x2cf/0x344
[<c11bad72>] ? pch_uart_interrupt+0x17/0x1e9
[<c11baebb>] pch_uart_interrupt+0x160/0x1e9
[<c10642fb>] handle_irq_event_percpu+0x25/0x127
[<c1064429>] handle_irq_event+0x2c/0x43
[<c1065e0d>] ? handle_fasteoi_irq+0x84/0x84
[<c1065eb9>] handle_edge_irq+0xac/0xce
<IRQ> [<c1003ecb>] ? do_IRQ+0x38/0x9d
[<c131db2e>] ? common_interrupt+0x2e/0x34
[<c105007b>] ? __lock_acquire+0x1f6/0x6bb
[<c131ca3d>] ? _raw_spin_unlock_irqrestore+0x38/0x52
[<c11b798b>] ? uart_start+0x2d/0x32
[<c11b7998>] ? uart_flush_chars+0x8/0xa
[<c11a7962>] ? n_tty_write+0x12c/0x1c6
[<c1027a73>] ? try_to_wake_up+0x251/0x251
[<c11a4d0b>] ? tty_write+0x169/0x1dc
[<c11a7836>] ? n_tty_ioctl+0xb7/0xb7
[<c1094841>] ? vfs_write+0x91/0x10d
[<c11a4ba2>] ? tty_write_lock+0x3c/0x3c
[<c1094a69>] ? sys_write+0x3e/0x63
[<c131d58c>] ? sysenter_do_call+0x12/0x32
Signed-off-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxxxxxxxx>
---
I'm not exactly sure if the dmaengine functions are allowed to be called from
IRQ context. But I found amba-pl011 which also calls device_prep_slave_sg from
IRQ context.
drivers/dma/pch_dma.c | 16 ++++++++--------
1 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/drivers/dma/pch_dma.c b/drivers/dma/pch_dma.c
index ff5b38f..bfb0f19 100644
--- a/drivers/dma/pch_dma.c
+++ b/drivers/dma/pch_dma.c
@@ -495,11 +495,11 @@ static int pd_alloc_chan_resources(struct dma_chan *chan)
list_add_tail(&desc->desc_node, &tmp_list);
}
- spin_lock_bh(&pd_chan->lock);
+ spin_lock_irq(&pd_chan->lock);
list_splice(&tmp_list, &pd_chan->free_list);
pd_chan->descs_allocated = i;
pd_chan->completed_cookie = chan->cookie = 1;
- spin_unlock_bh(&pd_chan->lock);
+ spin_unlock_irq(&pd_chan->lock);
pdc_enable_irq(chan, 1);
@@ -517,10 +517,10 @@ static void pd_free_chan_resources(struct dma_chan *chan)
BUG_ON(!list_empty(&pd_chan->active_list));
BUG_ON(!list_empty(&pd_chan->queue));
- spin_lock_bh(&pd_chan->lock);
+ spin_lock_irq(&pd_chan->lock);
list_splice_init(&pd_chan->free_list, &tmp_list);
pd_chan->descs_allocated = 0;
- spin_unlock_bh(&pd_chan->lock);
+ spin_unlock_irq(&pd_chan->lock);
list_for_each_entry_safe(desc, _d, &tmp_list, desc_node)
pci_pool_free(pd->pool, desc, desc->txd.phys);
@@ -536,10 +536,10 @@ static enum dma_status pd_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
dma_cookie_t last_completed;
int ret;
- spin_lock_bh(&pd_chan->lock);
+ spin_lock_irq(&pd_chan->lock);
last_completed = pd_chan->completed_cookie;
last_used = chan->cookie;
- spin_unlock_bh(&pd_chan->lock);
+ spin_unlock_irq(&pd_chan->lock);
ret = dma_async_is_complete(cookie, last_completed, last_used);
@@ -654,7 +654,7 @@ static int pd_device_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
if (cmd != DMA_TERMINATE_ALL)
return -ENXIO;
- spin_lock_bh(&pd_chan->lock);
+ spin_lock_irq(&pd_chan->lock);
pdc_set_mode(&pd_chan->chan, DMA_CTL0_DISABLE);
@@ -664,7 +664,7 @@ static int pd_device_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
list_for_each_entry_safe(desc, _d, &list, desc_node)
pdc_chain_complete(pd_chan, desc);
- spin_unlock_bh(&pd_chan->lock);
+ spin_unlock_irq(&pd_chan->lock);
return 0;
}
--
1.7.3.4
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