From: Dmitry Kasatkin Subject: [PATCH 04/11] omap-sham: replace flags operation with atomic bit operations Date: Thu, 2 Jun 2011 21:10:06 +0300 Message-ID: References: Cc: linux-crypto@vger.kernel.org, linux-omap@vger.kernel.org, Dmitry Kasatkin To: herbert@gondor.hengli.com.au Return-path: Received: from mail-ew0-f46.google.com ([209.85.215.46]:58398 "EHLO mail-ew0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753841Ab1FBSKf (ORCPT ); Thu, 2 Jun 2011 14:10:35 -0400 In-Reply-To: In-Reply-To: References: Sender: linux-crypto-owner@vger.kernel.org List-ID: From: Dmitry Kasatkin 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 --- drivers/crypto/omap-sham.c | 29 +++++++++++++---------------- 1 files changed, 13 insertions(+), 16 deletions(-) diff --git a/drivers/crypto/omap-sham.c b/drivers/crypto/omap-sham.c index 64698ad..208404e 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); -- 1.7.4.1