On 24/06/16 13:30, Herbert Xu wrote:
On Wed, Jun 22, 2016 at 04:23:38PM +0300, Tero Kristo wrote:Some of the call paths of OMAP SHA driver can avoid executing the next step of the crypto queue under tasklet; instead, execute the next step directly via function call. This avoids a costly round-trip via the scheduler giving a slight performance boost. Signed-off-by: Tero Kristo <t-kristo@xxxxxx> --- drivers/crypto/omap-sham.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/crypto/omap-sham.c b/drivers/crypto/omap-sham.c index 6247887..84a0027 100644 --- a/drivers/crypto/omap-sham.c +++ b/drivers/crypto/omap-sham.c @@ -242,6 +242,8 @@ static struct omap_sham_drv sham = { .lock = __SPIN_LOCK_UNLOCKED(sham.lock), }; +static void omap_sham_done_task(unsigned long data); + static inline u32 omap_sham_read(struct omap_sham_dev *dd, u32 offset) { return __raw_readl(dd->io_base + offset); @@ -1007,7 +1009,7 @@ static void omap_sham_finish_req(struct ahash_request *req, int err) req->base.complete(&req->base, err); /* handle new request */ - tasklet_schedule(&dd->done_task); + omap_sham_done_task((unsigned long)dd); }Hmm, what guarnatees that you won't run out of stack doing this?
Good question, I had a deeper look at the driver and it seems you are right... It may result in a recursion loop within the driver. I will dig this further and break the recursion if it indeed can call itself indefinitely.
My knowledge of the crypto stack (+ these drivers unfortunately) is still pretty limited, I appreciate your reviews a lot.
-Tero -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
