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| author | Ira Snyder <iws@ovro.caltech.edu> | 2012-01-26 10:59:54 +0000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2012-02-27 11:33:59 +1100 |
| commit | 75ff85a81680e5779383aa6210a4f89ed76e40ec (patch) | |
| tree | c327f25f2a51fc32382f0fcff4fee7c0532b6f15 /drivers/misc | |
| parent | 6d45584fdc202fd30da655120412210153429104 (diff) | |
| download | linux-75ff85a81680e5779383aa6210a4f89ed76e40ec.tar.gz linux-75ff85a81680e5779383aa6210a4f89ed76e40ec.tar.xz linux-75ff85a81680e5779383aa6210a4f89ed76e40ec.zip | |
carma-fpga: fix lockdep warning
Lockdep occasionally complains with the message:
INFO: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected
This is caused by calling videobuf_dma_unmap() under spin_lock_irq(). To
fix the warning, we drop the lock before unmapping and freeing the
buffer.
Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'drivers/misc')
| -rw-r--r-- | drivers/misc/carma/carma-fpga.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/drivers/misc/carma/carma-fpga.c b/drivers/misc/carma/carma-fpga.c index 14e974b2a781..4fd896deda0d 100644 --- a/drivers/misc/carma/carma-fpga.c +++ b/drivers/misc/carma/carma-fpga.c @@ -1079,6 +1079,7 @@ static ssize_t data_read(struct file *filp, char __user *ubuf, size_t count, struct fpga_reader *reader = filp->private_data; struct fpga_device *priv = reader->priv; struct list_head *used = &priv->used; + bool drop_buffer = false; struct data_buf *dbuf; size_t avail; void *data; @@ -1166,10 +1167,12 @@ have_buffer: * One of two things has happened, the device is disabled, or the * device has been reconfigured underneath us. In either case, we * should just throw away the buffer. + * + * Lockdep complains if this is done under the spinlock, so we + * handle it during the unlock path. */ if (!priv->enabled || dbuf->size != priv->bufsize) { - videobuf_dma_unmap(priv->dev, &dbuf->vb); - data_free_buffer(dbuf); + drop_buffer = true; goto out_unlock; } @@ -1178,6 +1181,12 @@ have_buffer: out_unlock: spin_unlock_irq(&priv->lock); + + if (drop_buffer) { + videobuf_dma_unmap(priv->dev, &dbuf->vb); + data_free_buffer(dbuf); + } + return count; } |