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| author | Amit Shah <amit.shah@redhat.com> | 2009-12-21 21:26:45 +0530 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2010-02-24 14:22:53 +1030 |
| commit | b766ceed5bbf04ae153389f5a15f53b9b6106a35 (patch) | |
| tree | 92a5769e001f6eb7888f287c3917608137c53033 /drivers/char/virtio_console.c | |
| parent | 17634ba25544d60af1968982929150efad755032 (diff) | |
| download | lwn-b766ceed5bbf04ae153389f5a15f53b9b6106a35.tar.gz lwn-b766ceed5bbf04ae153389f5a15f53b9b6106a35.zip | |
virtio: console: Prepare for writing to userspace buffers
When ports get advertised as char devices, the buffers will come from
userspace. Equip the fill_readbuf function with the ability to write
to userspace buffers.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'drivers/char/virtio_console.c')
| -rw-r--r-- | drivers/char/virtio_console.c | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index a70f2b3a9e64..8e447e1e12bc 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -358,7 +358,8 @@ fail: * Give out the data that's requested from the buffer that we have * queued up. */ -static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count) +static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count, + bool to_user) { struct port_buffer *buf; unsigned long flags; @@ -367,12 +368,18 @@ static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count) return 0; buf = port->inbuf; - if (out_count > buf->len - buf->offset) - out_count = buf->len - buf->offset; + out_count = min(out_count, buf->len - buf->offset); - memcpy(out_buf, buf->buf + buf->offset, out_count); + if (to_user) { + ssize_t ret; + + ret = copy_to_user(out_buf, buf->buf + buf->offset, out_count); + if (ret) + return -EFAULT; + } else { + memcpy(out_buf, buf->buf + buf->offset, out_count); + } - /* Return the number of bytes actually copied */ buf->offset += out_count; if (buf->offset == buf->len) { @@ -388,6 +395,7 @@ static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count) spin_unlock_irqrestore(&port->inbuf_lock, flags); } + /* Return the number of bytes actually copied */ return out_count; } @@ -431,7 +439,7 @@ static int get_chars(u32 vtermno, char *buf, int count) /* If we don't have an input queue yet, we can't get input. */ BUG_ON(!port->in_vq); - return fill_readbuf(port, buf, count); + return fill_readbuf(port, buf, count, false); } static void resize_console(struct port *port) |