[PATCH 6/6] staging: sm750fb: Spinlock and unlock in the same block

From: Lorenzo Stoakes
Date: Tue Mar 10 2015 - 21:29:25 EST


This patch combines spinlock locks and unlocks together in the same block rather
than occurring in separate blocks preventing a possible deadlock. This fixes the
following sparse warnings:-

drivers/staging/sm750fb/sm750.c:218:22: warning: context imbalance in 'lynxfb_ops_fillrect' - different lock contexts for basic block
drivers/staging/sm750fb/sm750.c:241:22: warning: context imbalance in 'lynxfb_ops_copyarea' - different lock contexts for basic block
drivers/staging/sm750fb/sm750.c:282:22: warning: context imbalance in 'lynxfb_ops_imageblit' - different lock contexts for basic block

Unfortunately this change involves code (and comment) duplication.

Signed-off-by: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
---
drivers/staging/sm750fb/sm750.c | 76 +++++++++++++++++++++++------------------
1 file changed, 43 insertions(+), 33 deletions(-)

diff --git a/drivers/staging/sm750fb/sm750.c b/drivers/staging/sm750fb/sm750.c
index 3e36b6a..58c7518 100644
--- a/drivers/staging/sm750fb/sm750.c
+++ b/drivers/staging/sm750fb/sm750.c
@@ -56,23 +56,6 @@ static char * g_settings = NULL;
static int g_dualview = 0;
static char * g_option = NULL;

-/* if not use spin_lock,system will die if user load driver
- * and immediatly unload driver frequently (dual)*/
-static inline void myspin_lock(spinlock_t * sl){
- struct lynx_share * share;
- share = container_of(sl,struct lynx_share,slock);
- if(share->dual){
- spin_lock(sl);
- }
-}
-
-static inline void myspin_unlock(spinlock_t * sl){
- struct lynx_share * share;
- share = container_of(sl,struct lynx_share,slock);
- if(share->dual){
- spin_unlock(sl);
- }
-}
static const struct fb_videomode lynx750_ext[] = {
/* 1024x600-60 VESA [1.71:1] */
{NULL, 60, 1024, 600, 20423, 144, 40, 18, 1, 104, 3,
@@ -209,13 +192,22 @@ static void lynxfb_ops_fillrect(struct fb_info* info,const struct fb_fillrect* r
color = (Bpp == 1)?region->color:((u32*)info->pseudo_palette)[region->color];
rop = ( region->rop != ROP_COPY ) ? HW_ROP2_XOR:HW_ROP2_COPY;

- myspin_lock(&share->slock);
- share->accel.de_fillrect(&share->accel,
- base,pitch,Bpp,
- region->dx,region->dy,
- region->width,region->height,
- color,rop);
- myspin_unlock(&share->slock);
+ /* if not use spin_lock,system will die if user load driver
+ * and immediatly unload driver frequently (dual)*/
+ if (share->dual) {
+ spin_lock(&share->slock);
+ share->accel.de_fillrect(&share->accel,
+ base,pitch,Bpp,
+ region->dx,region->dy,
+ region->width,region->height,
+ color,rop);
+ spin_unlock(&share->slock);
+ } else
+ share->accel.de_fillrect(&share->accel,
+ base,pitch,Bpp,
+ region->dx,region->dy,
+ region->width,region->height,
+ color,rop);
}

static void lynxfb_ops_copyarea(struct fb_info * info,const struct fb_copyarea * region)
@@ -233,12 +225,20 @@ static void lynxfb_ops_copyarea(struct fb_info * info,const struct fb_copyarea *
pitch = info->fix.line_length;
Bpp = info->var.bits_per_pixel >> 3;

- myspin_lock(&share->slock);
- share->accel.de_copyarea(&share->accel,
- base,pitch,region->sx,region->sy,
- base,pitch,Bpp,region->dx,region->dy,
- region->width,region->height,HW_ROP2_COPY);
- myspin_unlock(&share->slock);
+ /* if not use spin_lock,system will die if user load driver
+ * and immediatly unload driver frequently (dual)*/
+ if (share->dual) {
+ spin_lock(&share->slock);
+ share->accel.de_copyarea(&share->accel,
+ base,pitch,region->sx,region->sy,
+ base,pitch,Bpp,region->dx,region->dy,
+ region->width,region->height,HW_ROP2_COPY);
+ spin_unlock(&share->slock);
+ } else
+ share->accel.de_copyarea(&share->accel,
+ base,pitch,region->sx,region->sy,
+ base,pitch,Bpp,region->dx,region->dy,
+ region->width,region->height,HW_ROP2_COPY);
}

static void lynxfb_ops_imageblit(struct fb_info*info,const struct fb_image* image)
@@ -272,14 +272,24 @@ static void lynxfb_ops_imageblit(struct fb_info*info,const struct fb_image* imag
}
return;
_do_work:
- myspin_lock(&share->slock);
- share->accel.de_imageblit(&share->accel,
+ /* if not use spin_lock,system will die if user load driver
+ * and immediatly unload driver frequently (dual)*/
+ if (share->dual) {
+ spin_lock(&share->slock);
+ share->accel.de_imageblit(&share->accel,
+ image->data,image->width>>3,0,
+ base,pitch,Bpp,
+ image->dx,image->dy,
+ image->width,image->height,
+ fgcol,bgcol,HW_ROP2_COPY);
+ spin_unlock(&share->slock);
+ } else
+ share->accel.de_imageblit(&share->accel,
image->data,image->width>>3,0,
base,pitch,Bpp,
image->dx,image->dy,
image->width,image->height,
fgcol,bgcol,HW_ROP2_COPY);
- myspin_unlock(&share->slock);
}

static int lynxfb_ops_pan_display(struct fb_var_screeninfo *var,
--
2.3.2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/