On Tue, Jun 20, 2017 at 06:50:13PM +0200, Dhananjay Balan wrote:
> The locking and unlocking code used by copy routines is common, so
> moved it to a macro.
>
> Signed-off-by: Dhananjay Balan <mail@xxxxxxxxx>
> ---
> drivers/staging/sm750fb/sm750.c | 81 ++++++++++++++++-------------------------
> 1 file changed, 31 insertions(+), 50 deletions(-)
>
> diff --git a/drivers/staging/sm750fb/sm750.c b/drivers/staging/sm750fb/sm750.c
> index 386d4adcd91d..d8ab83aea46d 100644
> --- a/drivers/staging/sm750fb/sm750.c
> +++ b/drivers/staging/sm750fb/sm750.c
> @@ -156,12 +156,25 @@ static int lynxfb_ops_cursor(struct fb_info *info, struct fb_cursor *fbcursor)
> return 0;
> }
>
> +/*
> + * If not using spin_lock, system will die if user frequently loads and
> + * immediately unloads driver (dual)
> + */
> +#define dual_safe_call(func, ...) \
> + do { \
> + if (sm750_dev->fb_count > 1) \
> + spin_lock(&sm750_dev->slock); \
> + func(__VA_ARGS__); \
> + if (sm750_dev->fb_count > 1) \
> + spin_unlock(&sm750_dev->slock); \
> + } while (0)
> +
I feel like this is the wrong approach. You could just make a small
lock function and a small unlock function. Except that if statement
seems kind of bogus. What happens if ->fb_count is 0 when we lock and
1 when we unlock? Why not lock unconditionally? It is not likely to be
contested if there are no other users.
> static void lynxfb_ops_fillrect(struct fb_info *info,
> const struct fb_fillrect *region)
> {
> struct lynxfb_par *par;
> struct sm750_dev *sm750_dev;
> - unsigned int base, pitch, Bpp, rop;
> + unsigned int base, pitch, bit_pp, rop;
This part has nothing to do with locking... *frowny face*
regards,
dan carpenter
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