| Message ID | 1466601840-18486-6-git-send-email-t-kristo@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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@ti.com> > --- > 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?
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@ti.com> >> --- >> 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
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); } static int omap_sham_handle_queue(struct omap_sham_dev *dd,
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@ti.com> --- drivers/crypto/omap-sham.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)