[PATCHv2 2/6] omap-aes: redundant locking is removed

Dmitry Kasatkin
2010-11-30T08:13:28Z

Submitting request involved double locking for enqueuing and
dequeuing. Now it is done under the same lock.

FLAGS_BUSY is now handled under the same lock.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@nokia.com>
---
drivers/crypto/omap-aes.c | 70 ++++++++++++++++++++------------------------
1 files changed, 32 insertions(+), 38 deletions(-)

diff --git a/drivers/crypto/omap-aes.c b/drivers/crypto/omap-aes.c
index 41c91f3..2d8f72e 100644
--- a/drivers/crypto/omap-aes.c
+++ b/drivers/crypto/omap-aes.c
@@ -78,7 +78,7 @@
#define FLAGS_NEW_IV BIT(5)
#define FLAGS_INIT BIT(6)
#define FLAGS_FAST BIT(7)
-#define FLAGS_BUSY 8
+#define FLAGS_BUSY BIT(8)

struct omap_aes_ctx {
struct omap_aes_dev *dd;
@@ -179,9 +179,8 @@ static int omap_aes_wait(struct omap_aes_dev *dd, u32 offset, u32 bit)

static int omap_aes_hw_init(struct omap_aes_dev *dd)
{
- int err = 0;
-
clk_enable(dd->iclk);
+
if (!(dd->flags & FLAGS_INIT)) {
/* is it necessary to reset before every operation? */
omap_aes_write_mask(dd, AES_REG_MASK, AES_REG_MASK_SOFTRESET,
@@ -193,18 +192,15 @@ static int omap_aes_hw_init(struct omap_aes_dev *dd)
__asm__ __volatile__("nop");
__asm__ __volatile__("nop");

- err = omap_aes_wait(dd, AES_REG_SYSSTATUS,
- AES_REG_SYSSTATUS_RESETDONE);
- if (!err)
- dd->flags |= FLAGS_INIT;
+ if (omap_aes_wait(dd, AES_REG_SYSSTATUS,
+ AES_REG_SYSSTATUS_RESETDONE)) {
+ clk_disable(dd->iclk);
+ return -ETIMEDOUT;
+ }
+ dd->flags |= FLAGS_INIT;
}

- return err;
-}
-
-static void omap_aes_hw_cleanup(struct omap_aes_dev *dd)
-{
- clk_disable(dd->iclk);
+ return 0;
}

static void omap_aes_write_ctrl(struct omap_aes_dev *dd)
@@ -538,6 +534,8 @@ static void omap_aes_finish_req(struct omap_aes_dev *dd, int err)

pr_debug("err: %d\n", err);

+ dd->flags &= ~FLAGS_BUSY;
+
ctx = crypto_ablkcipher_ctx(crypto_ablkcipher_reqtfm(dd->req));

if (!dd->total)
@@ -553,7 +551,7 @@ static int omap_aes_crypt_dma_stop(struct omap_aes_dev *dd)

omap_aes_write_mask(dd, AES_REG_MASK, 0, AES_REG_MASK_START);

- omap_aes_hw_cleanup(dd);
+ clk_disable(dd->iclk);

omap_stop_dma(dd->dma_lch_in);
omap_stop_dma(dd->dma_lch_out);
@@ -580,22 +578,26 @@ static int omap_aes_crypt_dma_stop(struct omap_aes_dev *dd)
return err;
}

-static int omap_aes_handle_req(struct omap_aes_dev *dd)
+static int omap_aes_handle_req(struct omap_aes_dev *dd,
+ struct ablkcipher_request *req)
{
struct crypto_async_request *async_req, *backlog;
struct omap_aes_ctx *ctx;
struct omap_aes_reqctx *rctx;
- struct ablkcipher_request *req;
unsigned long flags;
-
- if (dd->total)
- goto start;
+ int err = 0;

spin_lock_irqsave(&dd->lock, flags);
+ if (req)
+ err = ablkcipher_enqueue_request(&dd->queue, req);
+ if (dd->flags & FLAGS_BUSY) {
+ spin_unlock_irqrestore(&dd->lock, flags);
+ return err;
+ }
backlog = crypto_get_backlog(&dd->queue);
async_req = crypto_dequeue_request(&dd->queue);
- if (!async_req)
- clear_bit(FLAGS_BUSY, &dd->flags);
+ if (async_req)
+ dd->flags |= FLAGS_BUSY;
spin_unlock_irqrestore(&dd->lock, flags);

if (!async_req)
@@ -637,20 +639,23 @@ static int omap_aes_handle_req(struct omap_aes_dev *dd)
if (!IS_ALIGNED(req->nbytes, AES_BLOCK_SIZE))
pr_err("request size is not exact amount of AES blocks\n");

-start:
- return omap_aes_crypt_dma_start(dd);
+ omap_aes_crypt_dma_start(dd);
+
+ return err;
}

static void omap_aes_task(unsigned long data)
{
struct omap_aes_dev *dd = (struct omap_aes_dev *)data;
- int err;

pr_debug("enter\n");

- err = omap_aes_crypt_dma_stop(dd);
+ omap_aes_crypt_dma_stop(dd);

- err = omap_aes_handle_req(dd);
+ if (dd->total)
+ omap_aes_crypt_dma_start(dd);
+ else
+ omap_aes_handle_req(dd, NULL);

pr_debug("exit\n");
}
@@ -661,8 +666,6 @@ static int omap_aes_crypt(struct ablkcipher_request *req, unsigned long mode)
crypto_ablkcipher_reqtfm(req));
struct omap_aes_reqctx *rctx = ablkcipher_request_ctx(req);
struct omap_aes_dev *dd;
- unsigned long flags;
- int err;

pr_debug("nbytes: %d, enc: %d, cbc: %d\n", req->nbytes,
!!(mode & FLAGS_ENCRYPT),
@@ -674,16 +677,7 @@ static int omap_aes_crypt(struct ablkcipher_request *req, unsigned long mode)

rctx->mode = mode;

- spin_lock_irqsave(&dd->lock, flags);
- err = ablkcipher_enqueue_request(&dd->queue, req);
- spin_unlock_irqrestore(&dd->lock, flags);
-
- if (!test_and_set_bit(FLAGS_BUSY, &dd->flags))
- omap_aes_handle_req(dd);
-
- pr_debug("exit\n");
-
- return err;
+ return omap_aes_handle_req(dd, req);
}

/* ********************** ALG API ************************************ */
--
1.7.0.4