net: ethernet: ti: cpdma: remove used_desc counter

The struct cpdma_desc_pool->used_desc field can be safely removed from
CPDMA driver (and hot patch) because used_descs counter is used just
for pool consistency check at CPDMA deinitialization and now this
check can be re-implemnted using gen_pool_size(pool->gen_pool) !=
gen_pool_avail(pool->gen_pool).
More over, this will allow to get rid of warnings in
cpdma_desc_pool_destro()-> WARN_ON(pool->used_desc) which may happen
because the used_descs is used unprotected, since CPDMA has been
switched to use genalloc, and may get wrong values on SMP.

Hence, remove used_desc from struct cpdma_desc_pool.

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Reviewed-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 11 deletions

diff --git a/drivers/net/ethernet/ti/davinci_cpdma.c b/drivers/net/ethernet/ti/davinci_cpdma.c
index 19e5f32a8a64..cf72b3390d85 100644
--- a/drivers/net/ethernet/ti/davinci_cpdma.c
+++ b/drivers/net/ethernet/ti/davinci_cpdma.c
@@ -86,7 +86,7 @@ struct cpdma_desc_pool {
         void __iomem            *iomap;         /* ioremap map */
         void                    *cpumap;        /* dma_alloc map */
         int                     desc_size, mem_size;
-        int                     num_desc, used_desc;
+        int                     num_desc;
         struct device           *dev;
         struct gen_pool         *gen_pool;
 };
@@ -148,7 +148,10 @@ static void cpdma_desc_pool_destroy(struct cpdma_desc_pool *pool)
         if (!pool)
                 return;
 
-        WARN_ON(pool->used_desc);
+        WARN(gen_pool_size(pool->gen_pool) != gen_pool_avail(pool->gen_pool),
+             "cpdma_desc_pool size %d != avail %d",
+             gen_pool_size(pool->gen_pool),
+             gen_pool_avail(pool->gen_pool));
         if (pool->cpumap)
                 dma_free_coherent(pool->dev, pool->mem_size, pool->cpumap,
                                   pool->phys);
@@ -232,21 +235,14 @@ desc_from_phys(struct cpdma_desc_pool *pool, dma_addr_t dma)
 static struct cpdma_desc __iomem *
 cpdma_desc_alloc(struct cpdma_desc_pool *pool)
 {
-        struct cpdma_desc __iomem *desc = NULL;
-
-        desc = (struct cpdma_desc __iomem *)gen_pool_alloc(pool->gen_pool,
-                                                           pool->desc_size);
-        if (desc)
-                pool->used_desc++;
-
-        return desc;
+        return (struct cpdma_desc __iomem *)
+                gen_pool_alloc(pool->gen_pool, pool->desc_size);
 }
 
 static void cpdma_desc_free(struct cpdma_desc_pool *pool,
                             struct cpdma_desc __iomem *desc, int num_desc)
 {
         gen_pool_free(pool->gen_pool, (unsigned long)desc, pool->desc_size);
-        pool->used_desc--;
 }
 
 struct cpdma_ctlr *cpdma_ctlr_create(struct cpdma_params *params)