Messages in this thread Patch in this message | | | From | Eli Billauer <> | Subject | [PATCH] char: xillybus: Don't return -EFAULT on user-triggered flush | Date | Fri, 27 Mar 2015 11:56:06 +0300 |
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The API allows the application to flush a host-to-FPGA stream by calling write() with the data count set to zero. Before this patch, copy_from_user() was called with a non-zero byte count, which possibly made it attempt to read from unmapped user memory. Such attempts caused the driver to return -EFAULT instead of 0, even though the desired operation went through fine.
This patch ensures the driver returns 0 on a successful flush.
Signed-off-by: Eli Billauer <eli.billauer@gmail.com> --- drivers/char/xillybus/xillybus_core.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/drivers/char/xillybus/xillybus_core.c b/drivers/char/xillybus/xillybus_core.c index b827fa0..77d6c12 100644 --- a/drivers/char/xillybus/xillybus_core.c +++ b/drivers/char/xillybus/xillybus_core.c @@ -1237,6 +1237,8 @@ static ssize_t xillybus_write(struct file *filp, const char __user *userbuf, unsigned char *tail; int i; + howmany = 0; + end_offset_plus1 = bufpos >> channel->log2_element_size; -- 1.7.2.3
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