[PATCH] dma/coh901318: use simple_read_from_buffer

From: Nicolas Kaiser
Date: Fri Oct 22 2010 - 14:35:19 EST


* Arnd Bergmann <arnd@xxxxxxxx>:
> On Friday 22 October 2010 19:29:53 Nicolas Kaiser wrote:
> > If copy_to_user fails, the assigned error code instantly gets
> > overwritten, and the failure apparently ignored. Moreover,
> > shouldn't the error code be -EFAULT instead of -EINVAL?
>
> Looks good, but it would be even better to just use
> simple_read_from_buffer in this function, which takes care of
> a lot the other complexities as well.

Like this? (Sorry, untested.)

Signed-off-by: Nicolas Kaiser <nikai@xxxxxxxxx>
---
obsoletes patch "dma/coh901318: fix copy_to_user error path"

drivers/dma/coh901318.c | 12 +-----------
1 files changed, 1 insertions(+), 11 deletions(-)

diff --git a/drivers/dma/coh901318.c b/drivers/dma/coh901318.c
index ae2b871..e7d0f06 100644
--- a/drivers/dma/coh901318.c
+++ b/drivers/dma/coh901318.c
@@ -133,17 +133,7 @@ static int coh901318_debugfs_read(struct file *file, char __user *buf,
tmp += sprintf(tmp, "Pool alloc nbr %d\n", pool_count);
dev_size = tmp - dev_buf;

- /* No more to read if offset != 0 */
- if (*f_pos > dev_size)
- goto out;
-
- if (count > dev_size - *f_pos)
- count = dev_size - *f_pos;
-
- if (copy_to_user(buf, dev_buf + *f_pos, count))
- ret = -EINVAL;
- ret = count;
- *f_pos += count;
+ ret = simple_read_from_buffer(buf, count, f_pos, dev_buf, dev_size);

out:
kfree(dev_buf);
--
1.7.2.2
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