crypto: omap-sham - replace flags operation with atomic bit operations

Some flags are changed in interrupt handlers and verified in the tasklet.
There might be a race condition when tasklet is interrupted or another
cpu/core will run IRQ handler and tasklet in parallel.
Atomic bitops functions are now used instead of bitmask operations.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@nokia.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 13 insertions, 16 deletions

diff --git a/drivers/crypto/omap-sham.c b/drivers/crypto/omap-sham.c
index 64698adec0c1..208404e20ef7 100644
--- a/drivers/crypto/omap-sham.c
+++ b/drivers/crypto/omap-sham.c
@@ -240,7 +240,7 @@ static int omap_sham_hw_init(struct omap_sham_dev *dd)
 {
         clk_enable(dd->iclk);
 
-        if (!(dd->flags & BIT(FLAGS_INIT))) {
+        if (!test_bit(FLAGS_INIT, &dd->flags)) {
                 omap_sham_write_mask(dd, SHA_REG_MASK,
                         SHA_REG_MASK_SOFTRESET, SHA_REG_MASK_SOFTRESET);
 
@@ -248,7 +248,7 @@ static int omap_sham_hw_init(struct omap_sham_dev *dd)
                                         SHA_REG_SYSSTATUS_RESETDONE))
                         return -ETIMEDOUT;
 
-                dd->flags |= BIT(FLAGS_INIT);
+                set_bit(FLAGS_INIT, &dd->flags);
                 dd->err = 0;
         }
 
@@ -303,7 +303,7 @@ static int omap_sham_xmit_cpu(struct omap_sham_dev *dd, const u8 *buf,
                 return -ETIMEDOUT;
 
         if (final)
-                ctx->flags |= BIT(FLAGS_FINAL); /* catch last interrupt */
+                set_bit(FLAGS_FINAL, &ctx->flags); /* catch last interrupt */
 
         len32 = DIV_ROUND_UP(length, sizeof(u32));
 
@@ -336,9 +336,9 @@ static int omap_sham_xmit_dma(struct omap_sham_dev *dd, dma_addr_t dma_addr,
         ctx->digcnt += length;
 
         if (final)
-                ctx->flags |= BIT(FLAGS_FINAL); /* catch last interrupt */
+                set_bit(FLAGS_FINAL, &ctx->flags); /* catch last interrupt */
 
-        dd->flags |= BIT(FLAGS_DMA_ACTIVE);
+        set_bit(FLAGS_DMA_ACTIVE, &dd->flags);
 
         omap_start_dma(dd->dma_lch);
 
@@ -642,7 +642,7 @@ static void omap_sham_finish_req(struct ahash_request *req, int err)
 
         if (!err) {
                 omap_sham_copy_hash(req, 1);
-                if (ctx->flags & BIT(FLAGS_FINAL))
+                if (test_bit(FLAGS_FINAL, &ctx->flags))
                         err = omap_sham_finish(req);
         } else {
                 ctx->flags |= BIT(FLAGS_ERROR);
@@ -666,14 +666,14 @@ static int omap_sham_handle_queue(struct omap_sham_dev *dd,
         spin_lock_irqsave(&dd->lock, flags);
         if (req)
                 ret = ahash_enqueue_request(&dd->queue, req);
-        if (dd->flags & BIT(FLAGS_BUSY)) {
+        if (test_bit(FLAGS_BUSY, &dd->flags)) {
                 spin_unlock_irqrestore(&dd->lock, flags);
                 return ret;
         }
         backlog = crypto_get_backlog(&dd->queue);
         async_req = crypto_dequeue_request(&dd->queue);
         if (async_req)
-                dd->flags |= BIT(FLAGS_BUSY);
+                set_bit(FLAGS_BUSY, &dd->flags);
         spin_unlock_irqrestore(&dd->lock, flags);
 
         if (!async_req)
@@ -1037,13 +1037,10 @@ static void omap_sham_done_task(unsigned long data)
         struct omap_sham_reqctx *ctx = ahash_request_ctx(req);
         int ready = 0, err = 0;
 
-        if (ctx->flags & BIT(FLAGS_OUTPUT_READY)) {
-                ctx->flags &= ~BIT(FLAGS_OUTPUT_READY);
+        if (test_and_clear_bit(FLAGS_OUTPUT_READY, &ctx->flags))
                 ready = 1;
-        }
 
-        if (dd->flags & BIT(FLAGS_DMA_ACTIVE)) {
-                dd->flags &= ~BIT(FLAGS_DMA_ACTIVE);
+        if (test_and_clear_bit(FLAGS_DMA_ACTIVE, &dd->flags)) {
                 omap_sham_update_dma_stop(dd);
                 if (!dd->err)
                         err = omap_sham_update_dma_start(dd);
@@ -1077,7 +1074,7 @@ static irqreturn_t omap_sham_irq(int irq, void *dev_id)
                 return IRQ_HANDLED;
         }
 
-        if (unlikely(ctx->flags & BIT(FLAGS_FINAL)))
+        if (unlikely(test_bit(FLAGS_FINAL, &ctx->flags)))
                 /* final -> allow device to go to power-saving mode */
                 omap_sham_write_mask(dd, SHA_REG_CTRL, 0, SHA_REG_CTRL_LENGTH);
 
@@ -1085,7 +1082,7 @@ static irqreturn_t omap_sham_irq(int irq, void *dev_id)
                                  SHA_REG_CTRL_OUTPUT_READY);
         omap_sham_read(dd, SHA_REG_CTRL);
 
-        ctx->flags |= BIT(FLAGS_OUTPUT_READY);
+        set_bit(FLAGS_OUTPUT_READY, &ctx->flags);
         dd->err = 0;
         tasklet_schedule(&dd->done_task);
 
@@ -1099,7 +1096,7 @@ static void omap_sham_dma_callback(int lch, u16 ch_status, void *data)
         if (ch_status != OMAP_DMA_BLOCK_IRQ) {
                 pr_err("omap-sham DMA error status: 0x%hx\n", ch_status);
                 dd->err = -EIO;
-                dd->flags &= ~BIT(FLAGS_INIT); /* request to re-initialize */
+                clear_bit(FLAGS_INIT, &dd->flags);/* request to re-initialize */
         }
 
         tasklet_schedule(&dd->done_task);