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wimax/i2400m: fix the bootmode RX deadlock in SDIO driver

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i2400ms_bus_bm_wait_for_ack() causes a race condition. It happens
because this function clears i2400ms->bm_ack_size before waiting for
an interrupt, which is set by the interrupt service routine i2400ms_rx()
to indicate reception and size of received data; thus, if the interrupt
came right before the clearing/waiting, it is lost.

The fix is clear the bm_ack_size to -EINPROGRESS before we are enabling
the RX interrupt configuration in i2400ms_rx_setup(). Then everytime
when the interrupt service routine i2400ms_rx() is invoked during bootmode,
bm_ack_size is updated with the actual rx_size and it is cleared to
-EINPROGRESS again after the RX data is handled.

Signed-off-by: Cindy H Kao <cindy.h.kao@intel.com>
Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>
This commit is contained in:
Cindy H Kao 2009-08-27 15:25:12 -07:00 committed by Inaky Perez-Gonzalez
parent 663ebb4aa2
commit 5b45bfe501
2 changed files with 11 additions and 4 deletions
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8
drivers/net/wimax/i2400m/sdio-fw.c
View File

@ -177,10 +177,6 @@ ssize_t i2400ms_bus_bm_wait_for_ack(struct i2400m *i2400m,
d_fnstart(5, dev, "(i2400m %p ack %p size %zu)\n",
i2400m, ack, ack_size);
spin_lock(&i2400m->rx_lock);
i2400ms->bm_ack_size = -EINPROGRESS;
spin_unlock(&i2400m->rx_lock);
result = wait_event_timeout(i2400ms->bm_wfa_wq,
i2400ms->bm_ack_size != -EINPROGRESS,
2 * HZ);
@ -199,6 +195,10 @@ ssize_t i2400ms_bus_bm_wait_for_ack(struct i2400m *i2400m,
size = min(ack_size, i2400ms->bm_ack_size);
memcpy(ack, i2400m->bm_ack_buf, size);
}
/*
* Remember always to clear the bm_ack_size to -EINPROGRESS
* after the RX data is processed
*/
i2400ms->bm_ack_size = -EINPROGRESS;
spin_unlock(&i2400m->rx_lock);

7
drivers/net/wimax/i2400m/sdio-rx.c
View File

@ -234,6 +234,13 @@ int i2400ms_rx_setup(struct i2400ms *i2400ms)
init_waitqueue_head(&i2400ms->bm_wfa_wq);
spin_lock(&i2400m->rx_lock);
i2400ms->bm_wait_result = -EINPROGRESS;
/*
* Before we are about to enable the RX interrupt, make sure
* bm_ack_size is cleared to -EINPROGRESS which indicates
* no RX interrupt happened yet or the previous interrupt
* has been handled, we are ready to take the new interrupt
*/
i2400ms->bm_ack_size = -EINPROGRESS;
spin_unlock(&i2400m->rx_lock);
sdio_claim_host(func);