| Message ID | 20221221200513.676744-1-nfrayer@baylibre.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | soc: ti: k3-ringacc: Add try_module_get() to k3_dmaring_request_dual_ring() | expand |
Hi Nicolas, On 21/12/2022 22:05, Nicolas Frayer wrote: > When the k3 ring accelerator driver has been modified to add module build > support, try_module_get() and module_put() have been added to update the > module refcnt. One code path has not been updated and it has introduced > an issue where the refcnt is decremented by module_put() in > k3_ringacc_ring_free() without being incremented previously. > Adding try_module_get() to k3_dmaring_request_dual_ring() ensures the > refcnt is kept up to date. Good catch! I had never had my hands on a device with DMSS (BCDMA/PKDMA) and the original module support was developed and tested on devices with UDMA. can you add the fixes tag along with my reviewed by tag? Fixes: c07f216a8b72 ("soc: ti: k3-ringacc: Allow the driver to be built as module") Reviewed-by: Peter Ujfalusi <peter.ujfalusi@gmail.com> > > Signed-off-by: Nicolas Frayer <nfrayer@baylibre.com> > --- > drivers/soc/ti/k3-ringacc.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/soc/ti/k3-ringacc.c b/drivers/soc/ti/k3-ringacc.c > index e01e4d815230a..8f131368a7586 100644 > --- a/drivers/soc/ti/k3-ringacc.c > +++ b/drivers/soc/ti/k3-ringacc.c > @@ -406,6 +406,11 @@ static int k3_dmaring_request_dual_ring(struct k3_ringacc *ringacc, int fwd_id, > > mutex_lock(&ringacc->req_lock); > > + if (!try_module_get(ringacc->dev->driver->owner)) { > + ret = -EINVAL; > + goto err_module_get; > + } > + > if (test_bit(fwd_id, ringacc->rings_inuse)) { > ret = -EBUSY; > goto error; > @@ -421,6 +426,8 @@ static int k3_dmaring_request_dual_ring(struct k3_ringacc *ringacc, int fwd_id, > return 0; > > error: > + module_put(ringacc->dev->driver->owner); > +err_module_get: > mutex_unlock(&ringacc->req_lock); > return ret; > }
Le sam. 24 déc. 2022 à 23:01, Péter Ujfalusi <peter.ujfalusi@gmail.com> a écrit : > > Hi Nicolas, > > On 21/12/2022 22:05, Nicolas Frayer wrote: > > When the k3 ring accelerator driver has been modified to add module build > > support, try_module_get() and module_put() have been added to update the > > module refcnt. One code path has not been updated and it has introduced > > an issue where the refcnt is decremented by module_put() in > > k3_ringacc_ring_free() without being incremented previously. > > Adding try_module_get() to k3_dmaring_request_dual_ring() ensures the > > refcnt is kept up to date. > > Good catch! > I had never had my hands on a device with DMSS (BCDMA/PKDMA) and the > original module support was developed and tested on devices with UDMA. > > can you add the fixes tag along with my reviewed by tag? > > Fixes: c07f216a8b72 ("soc: ti: k3-ringacc: Allow the driver to be built as module") > Reviewed-by: Peter Ujfalusi <peter.ujfalusi@gmail.com> > > > > > Signed-off-by: Nicolas Frayer <nfrayer@baylibre.com> > > --- > > drivers/soc/ti/k3-ringacc.c | 7 +++++++ > > 1 file changed, 7 insertions(+) > > > > diff --git a/drivers/soc/ti/k3-ringacc.c b/drivers/soc/ti/k3-ringacc.c > > index e01e4d815230a..8f131368a7586 100644 > > --- a/drivers/soc/ti/k3-ringacc.c > > +++ b/drivers/soc/ti/k3-ringacc.c > > @@ -406,6 +406,11 @@ static int k3_dmaring_request_dual_ring(struct k3_ringacc *ringacc, int fwd_id, > > > > mutex_lock(&ringacc->req_lock); > > > > + if (!try_module_get(ringacc->dev->driver->owner)) { > > + ret = -EINVAL; > > + goto err_module_get; > > + } > > + > > if (test_bit(fwd_id, ringacc->rings_inuse)) { > > ret = -EBUSY; > > goto error; > > @@ -421,6 +426,8 @@ static int k3_dmaring_request_dual_ring(struct k3_ringacc *ringacc, int fwd_id, > > return 0; > > > > error: > > + module_put(ringacc->dev->driver->owner); > > +err_module_get: > > mutex_unlock(&ringacc->req_lock); > > return ret; > > } > > -- > Péter Thanks Peter, I'll send a v2 with the tags.
diff --git a/drivers/soc/ti/k3-ringacc.c b/drivers/soc/ti/k3-ringacc.c index e01e4d815230a..8f131368a7586 100644 --- a/drivers/soc/ti/k3-ringacc.c +++ b/drivers/soc/ti/k3-ringacc.c @@ -406,6 +406,11 @@ static int k3_dmaring_request_dual_ring(struct k3_ringacc *ringacc, int fwd_id, mutex_lock(&ringacc->req_lock); + if (!try_module_get(ringacc->dev->driver->owner)) { + ret = -EINVAL; + goto err_module_get; + } + if (test_bit(fwd_id, ringacc->rings_inuse)) { ret = -EBUSY; goto error; @@ -421,6 +426,8 @@ static int k3_dmaring_request_dual_ring(struct k3_ringacc *ringacc, int fwd_id, return 0; error: + module_put(ringacc->dev->driver->owner); +err_module_get: mutex_unlock(&ringacc->req_lock); return ret; }
When the k3 ring accelerator driver has been modified to add module build support, try_module_get() and module_put() have been added to update the module refcnt. One code path has not been updated and it has introduced an issue where the refcnt is decremented by module_put() in k3_ringacc_ring_free() without being incremented previously. Adding try_module_get() to k3_dmaring_request_dual_ring() ensures the refcnt is kept up to date. Signed-off-by: Nicolas Frayer <nfrayer@baylibre.com> --- drivers/soc/ti/k3-ringacc.c | 7 +++++++ 1 file changed, 7 insertions(+)