On Tue, Nov 14, 2017 at 10:52:08AM -0700, kys@xxxxxxxxxxxxxxxxxxxxxx wrote:
> From: Stephen Hemminger <stephen@xxxxxxxxxxxxxxxxxx>
>
> hv_get_ringbuffer_availbytes is only used by the debug info
> routine so make it static. Also, add READ_ONCE() to avoid any
> possible issues with potentially volatile index values.
>
> Signed-off-by: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>
> Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
> ---
> drivers/hv/ring_buffer.c | 23 +++++++++++++++++++++++
> include/linux/hyperv.h | 22 ----------------------
> 2 files changed, 23 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
> index 12eb8ca..50e0714 100644
> --- a/drivers/hv/ring_buffer.c
> +++ b/drivers/hv/ring_buffer.c
> @@ -140,6 +140,29 @@ static u32 hv_copyto_ringbuffer(
> return start_write_offset;
> }
>
> +/*
> + *
> + * hv_get_ringbuffer_availbytes()
> + *
> + * Get number of bytes available to read and to write to
> + * for the specified ring buffer
> + */
> +static void
> +hv_get_ringbuffer_availbytes(const struct hv_ring_buffer_info *rbi,
> + u32 *read, u32 *write)
> +{
> + u32 read_loc, write_loc, dsize;
> +
> + /* Capture the read/write indices before they changed */
> + read_loc = READ_ONCE(rbi->ring_buffer->read_index);
> + write_loc = READ_ONCE(rbi->ring_buffer->write_index);
> + dsize = rbi->ring_datasize;
> +
> + *write = write_loc >= read_loc ? dsize - (write_loc - read_loc) :
> + read_loc - write_loc;
> + *read = dsize - *write;
> +}
> +
> /* Get various debug metrics for the specified ring buffer. */
> void hv_ringbuffer_get_debuginfo(const struct hv_ring_buffer_info *ring_info,
> struct hv_ring_buffer_debug_info *debug_info)
> diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
> index 6c93366..93bd6fc 100644
> --- a/include/linux/hyperv.h
> +++ b/include/linux/hyperv.h
> @@ -127,28 +127,6 @@ struct hv_ring_buffer_info {
> u32 priv_read_index;
> };
>
> -/*
> - *
> - * hv_get_ringbuffer_availbytes()
> - *
> - * Get number of bytes available to read and to write to
> - * for the specified ring buffer
> - */
> -static inline void
> -hv_get_ringbuffer_availbytes(const struct hv_ring_buffer_info *rbi,
> - u32 *read, u32 *write)
> -{
> - u32 read_loc, write_loc, dsize;
> -
> - /* Capture the read/write indices before they changed */
> - read_loc = rbi->ring_buffer->read_index;
> - write_loc = rbi->ring_buffer->write_index;
> - dsize = rbi->ring_datasize;
> -
> - *write = write_loc >= read_loc ? dsize - (write_loc - read_loc) :
> - read_loc - write_loc;
> - *read = dsize - *write;
> -}
>
> static inline u32 hv_get_bytes_to_read(const struct hv_ring_buffer_info *rbi)
> {
> --
> 1.7.1
This breaks the build.
Please be more careful...
greg k-h
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