dmaengine: PL08x: get rid of write only pool_ctr and free_txd locking

The free function says the pl08x lock should be taken before calling
it.  However, the DMA pool allocation/freeing is already properly
locked.  The only thing that would need this is pool_ctr, which
happens to be a write-only variable.

Let's get rid of this, and eliminate any need for additional locking
here.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index 9297240..a5d85b1 100644 (file)
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -247,7 +247,6 @@ struct pl08x_dma_chan {
  * @pd: platform data passed in from the platform/machine
  * @phy_chans: array of data for the physical channels
  * @pool: a pool for the LLI descriptors
- * @pool_ctr: counter of LLIs in the pool
  * @lli_buses: bitmask to or in to LLI pointer selecting AHB port for LLI
  * fetches
  * @mem_buses: set to indicate memory transfers on AHB2.
@@ -262,7 +261,6 @@ struct pl08x_driver_data {
        struct pl08x_platform_data *pd;
        struct pl08x_phy_chan *phy_chans;
        struct dma_pool *pool;
-       int pool_ctr;
        u8 lli_buses;
        u8 mem_buses;
 };
@@ -821,8 +819,6 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
                return 0;
        }
 
-       pl08x->pool_ctr++;
-
        bd.txd = txd;
        bd.lli_bus = (pl08x->lli_buses & PL08X_AHB2) ? PL080_LLI_LM_AHB2 : 0;
        cctl = txd->cctl;
@@ -1038,18 +1034,14 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
        return num_llis;
 }
 
-/* You should call this with the struct pl08x lock held */
 static void pl08x_free_txd(struct pl08x_driver_data *pl08x,
                           struct pl08x_txd *txd)
 {
        struct pl08x_sg *dsg, *_dsg;
 
-       /* Free the LLI */
        if (txd->llis_va)
                dma_pool_free(pl08x->pool, txd->llis_va, txd->llis_bus);
 
-       pl08x->pool_ctr--;
-
        list_for_each_entry_safe(dsg, _dsg, &txd->dsg_list, node) {
                list_del(&dsg->node);
                kfree(dsg);
@@ -1090,8 +1082,6 @@ static void pl08x_desc_free(struct virt_dma_desc *vd)
 {
        struct pl08x_txd *txd = to_pl08x_txd(&vd->tx);
        struct pl08x_dma_chan *plchan = to_pl08x_chan(vd->tx.chan);
-       struct pl08x_driver_data *pl08x = plchan->host;
-       unsigned long flags;
 
        if (!plchan->slave)
                pl08x_unmap_buffers(txd);
@@ -1099,9 +1089,7 @@ static void pl08x_desc_free(struct virt_dma_desc *vd)
        if (!txd->done)
                pl08x_release_mux(plchan);
 
-       spin_lock_irqsave(&pl08x->lock, flags);
        pl08x_free_txd(plchan->host, txd);
-       spin_unlock_irqrestore(&pl08x->lock, flags);
 }
 
 static void pl08x_free_txd_list(struct pl08x_driver_data *pl08x,