Instead of getting the epc_features from pci_epc_get_features() API, use
the cached pci_epf_test::epc_features value to avoid the NULL check. Since
the NULL check is already performed in pci_epf_test_bind(), having one more
check in pci_epf_test_core_init() is redundant and it is not possible to
hit the NULL pointer dereference. This also leads to the following smatch
warning:
drivers/pci/endpoint/functions/pci-epf-test.c:784 pci_epf_test_core_init()
error: we previously assumed 'epc_features' could be null (see line 747)
Reported-by: Dan Carpenter <[email protected]>
Closes: https://lore.kernel.org/linux-pci/[email protected]/
Signed-off-by: Manivannan Sadhasivam <[email protected]>
---
drivers/pci/endpoint/functions/pci-epf-test.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index 977fb79c1567..0d28f413cb07 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -743,11 +743,10 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
bool msi_capable = true;
int ret;
- epc_features = pci_epc_get_features(epc, epf->func_no, epf->vfunc_no);
- if (epc_features) {
- msix_capable = epc_features->msix_capable;
- msi_capable = epc_features->msi_capable;
- }
+ epc_features = epf_test->epc_features;
+
+ msix_capable = epc_features->msix_capable;
+ msi_capable = epc_features->msi_capable;
if (epf->vfunc_no <= 1) {
ret = pci_epc_write_header(epc, epf->func_no, epf->vfunc_no, header);
---
base-commit: 6e47dcb2ca223211c43c37497836cd9666c70674
change-id: 20240417-pci-epf-test-fix-2209ae22be80
Best regards,
--
Manivannan Sadhasivam <[email protected]>
On Wed, Apr 17, 2024 at 10:47:25PM +0530, Manivannan Sadhasivam wrote:
> Instead of getting the epc_features from pci_epc_get_features() API, use
> the cached pci_epf_test::epc_features value to avoid the NULL check. Since
> the NULL check is already performed in pci_epf_test_bind(), having one more
> check in pci_epf_test_core_init() is redundant and it is not possible to
> hit the NULL pointer dereference. This also leads to the following smatch
> warning:
>
> drivers/pci/endpoint/functions/pci-epf-test.c:784 pci_epf_test_core_init()
> error: we previously assumed 'epc_features' could be null (see line 747)
>
> Reported-by: Dan Carpenter <[email protected]>
> Closes: https://lore.kernel.org/linux-pci/[email protected]/
> Signed-off-by: Manivannan Sadhasivam <[email protected]>
I think you forgot:
Fixes: a01e7214bef9 ("PCI: endpoint: Remove "core_init_notifier" flag")
> ---
> drivers/pci/endpoint/functions/pci-epf-test.c | 9 ++++-----
> 1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> index 977fb79c1567..0d28f413cb07 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> @@ -743,11 +743,10 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
> bool msi_capable = true;
> int ret;
>
> - epc_features = pci_epc_get_features(epc, epf->func_no, epf->vfunc_no);
> - if (epc_features) {
> - msix_capable = epc_features->msix_capable;
> - msi_capable = epc_features->msi_capable;
> - }
> + epc_features = epf_test->epc_features;
How about:
index 977fb79c1567..4d6105c07ac0 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -735,7 +735,7 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
{
struct pci_epf_test *epf_test = epf_get_drvdata(epf);
struct pci_epf_header *header = epf->header;
- const struct pci_epc_features *epc_features;
+ const struct pci_epc_features *epc_features = epf_test->epc_features;
struct pci_epc *epc = epf->epc;
struct device *dev = &epf->dev;
bool linkup_notifier = false;
@@ -743,12 +743,6 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
bool msi_capable = true;
int ret;
- epc_features = pci_epc_get_features(epc, epf->func_no, epf->vfunc_no);
- if (epc_features) {
- msix_capable = epc_features->msix_capable;
- msi_capable = epc_features->msi_capable;
- }
-
if (epf->vfunc_no <= 1) {
ret = pci_epc_write_header(epc, epf->func_no, epf->vfunc_no, header);
if (ret) {
@@ -761,6 +755,7 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
if (ret)
return ret;
+ msi_capable = epc_features->msi_capable;
if (msi_capable) {
ret = pci_epc_set_msi(epc, epf->func_no, epf->vfunc_no,
epf->msi_interrupts);
@@ -770,6 +765,7 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
}
}
+ msix_capable = epc_features->msix_capable;
if (msix_capable) {
ret = pci_epc_set_msix(epc, epf->func_no, epf->vfunc_no,
epf->msix_interrupts,
@@ -814,11 +810,9 @@ static int pci_epf_test_alloc_space(struct pci_epf *epf)
void *base;
enum pci_barno test_reg_bar = epf_test->test_reg_bar;
enum pci_barno bar;
- const struct pci_epc_features *epc_features;
+ const struct pci_epc_features *epc_features = epf_test->epc_features;
size_t test_reg_size;
- epc_features = epf_test->epc_features;
-
test_reg_bar_size = ALIGN(sizeof(struct pci_epf_test_reg), 128);
msix_capable = epc_features->msix_capable;
Instead?
That way, we assign msi_capable/msix_capable just before the if-statement
where it is used. (Which matches how we already assign msix_capable just
before the if-statement in pci_epf_test_alloc_space().)
Kind regards,
Niklas
> +
> + msix_capable = epc_features->msix_capable;
> + msi_capable = epc_features->msi_capable;
>
> if (epf->vfunc_no <= 1) {
> ret = pci_epc_write_header(epc, epf->func_no, epf->vfunc_no, header);
>
> ---
> base-commit: 6e47dcb2ca223211c43c37497836cd9666c70674
> change-id: 20240417-pci-epf-test-fix-2209ae22be80
>
> Best regards,
> --
> Manivannan Sadhasivam <[email protected]>
>
On Wed, Apr 17, 2024 at 07:49:45PM +0200, Niklas Cassel wrote:
> @@ -761,6 +755,7 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
> if (ret)
> return ret;
>
> + msi_capable = epc_features->msi_capable;
> if (msi_capable) {
Or just: if (epc_features->msi_capable) {
;)
> ret = pci_epc_set_msi(epc, epf->func_no, epf->vfunc_no,
> epf->msi_interrupts);
regards,
dan carpenter
On Wed, Apr 17, 2024 at 07:49:45PM +0200, Niklas Cassel wrote:
> On Wed, Apr 17, 2024 at 10:47:25PM +0530, Manivannan Sadhasivam wrote:
> > Instead of getting the epc_features from pci_epc_get_features() API, use
> > the cached pci_epf_test::epc_features value to avoid the NULL check. Since
> > the NULL check is already performed in pci_epf_test_bind(), having one more
> > check in pci_epf_test_core_init() is redundant and it is not possible to
> > hit the NULL pointer dereference. This also leads to the following smatch
> > warning:
> >
> > drivers/pci/endpoint/functions/pci-epf-test.c:784 pci_epf_test_core_init()
> > error: we previously assumed 'epc_features' could be null (see line 747)
> >
> > Reported-by: Dan Carpenter <[email protected]>
> > Closes: https://lore.kernel.org/linux-pci/[email protected]/
> > Signed-off-by: Manivannan Sadhasivam <[email protected]>
>
> I think you forgot:
> Fixes: a01e7214bef9 ("PCI: endpoint: Remove "core_init_notifier" flag")
>
>
> > ---
> > drivers/pci/endpoint/functions/pci-epf-test.c | 9 ++++-----
> > 1 file changed, 4 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> > index 977fb79c1567..0d28f413cb07 100644
> > --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> > @@ -743,11 +743,10 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
> > bool msi_capable = true;
> > int ret;
> >
> > - epc_features = pci_epc_get_features(epc, epf->func_no, epf->vfunc_no);
> > - if (epc_features) {
> > - msix_capable = epc_features->msix_capable;
> > - msi_capable = epc_features->msi_capable;
> > - }
> > + epc_features = epf_test->epc_features;
>
> How about:
>
> index 977fb79c1567..4d6105c07ac0 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> @@ -735,7 +735,7 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
> {
> struct pci_epf_test *epf_test = epf_get_drvdata(epf);
> struct pci_epf_header *header = epf->header;
> - const struct pci_epc_features *epc_features;
> + const struct pci_epc_features *epc_features = epf_test->epc_features;
> struct pci_epc *epc = epf->epc;
> struct device *dev = &epf->dev;
> bool linkup_notifier = false;
> @@ -743,12 +743,6 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
> bool msi_capable = true;
> int ret;
>
> - epc_features = pci_epc_get_features(epc, epf->func_no, epf->vfunc_no);
> - if (epc_features) {
> - msix_capable = epc_features->msix_capable;
> - msi_capable = epc_features->msi_capable;
> - }
> -
> if (epf->vfunc_no <= 1) {
> ret = pci_epc_write_header(epc, epf->func_no, epf->vfunc_no, header);
> if (ret) {
> @@ -761,6 +755,7 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
> if (ret)
> return ret;
>
> + msi_capable = epc_features->msi_capable;
> if (msi_capable) {
> ret = pci_epc_set_msi(epc, epf->func_no, epf->vfunc_no,
> epf->msi_interrupts);
> @@ -770,6 +765,7 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
> }
> }
>
> + msix_capable = epc_features->msix_capable;
> if (msix_capable) {
> ret = pci_epc_set_msix(epc, epf->func_no, epf->vfunc_no,
> epf->msix_interrupts,
> @@ -814,11 +810,9 @@ static int pci_epf_test_alloc_space(struct pci_epf *epf)
> void *base;
> enum pci_barno test_reg_bar = epf_test->test_reg_bar;
> enum pci_barno bar;
> - const struct pci_epc_features *epc_features;
> + const struct pci_epc_features *epc_features = epf_test->epc_features;
> size_t test_reg_size;
>
> - epc_features = epf_test->epc_features;
> -
> test_reg_bar_size = ALIGN(sizeof(struct pci_epf_test_reg), 128);
>
> msix_capable = epc_features->msix_capable;
>
>
> Instead?
>
> That way, we assign msi_capable/msix_capable just before the if-statement
> where it is used. (Which matches how we already assign msix_capable just
> before the if-statement in pci_epf_test_alloc_space().)
..or just kill the local variables:
bool msi_capable/msix_capable in pci_epf_test_core_init(), and
bool msix_capable pci_epf_test_alloc_space()
and just do:
if (epc_features->msix_capable) / if (epc_features->msi_capable)
directly?
Kind regards,
Niklas
On Wed, Apr 17, 2024 at 07:49:45PM +0200, Niklas Cassel wrote:
> On Wed, Apr 17, 2024 at 10:47:25PM +0530, Manivannan Sadhasivam wrote:
> > Instead of getting the epc_features from pci_epc_get_features() API, use
> > the cached pci_epf_test::epc_features value to avoid the NULL check. Since
> > the NULL check is already performed in pci_epf_test_bind(), having one more
> > check in pci_epf_test_core_init() is redundant and it is not possible to
> > hit the NULL pointer dereference. This also leads to the following smatch
> > warning:
> >
> > drivers/pci/endpoint/functions/pci-epf-test.c:784 pci_epf_test_core_init()
> > error: we previously assumed 'epc_features' could be null (see line 747)
> >
> > Reported-by: Dan Carpenter <[email protected]>
> > Closes: https://lore.kernel.org/linux-pci/[email protected]/
> > Signed-off-by: Manivannan Sadhasivam <[email protected]>
>
> I think you forgot:
> Fixes: a01e7214bef9 ("PCI: endpoint: Remove "core_init_notifier" flag")
>
No, that's not the correct fixes tag I suppose. This redudant check is
introduced by commit, 5e50ee27d4a5 ("PCI: pci-epf-test: Add support to defer
core initialization") and this commit removes the redundant check (fixing smatch
warning is a side effect). So if the fixes tag needs to be added, then this
commit should be referenced.
>
> > ---
> > drivers/pci/endpoint/functions/pci-epf-test.c | 9 ++++-----
> > 1 file changed, 4 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> > index 977fb79c1567..0d28f413cb07 100644
> > --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> > @@ -743,11 +743,10 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
> > bool msi_capable = true;
> > int ret;
> >
> > - epc_features = pci_epc_get_features(epc, epf->func_no, epf->vfunc_no);
> > - if (epc_features) {
> > - msix_capable = epc_features->msix_capable;
> > - msi_capable = epc_features->msi_capable;
> > - }
> > + epc_features = epf_test->epc_features;
>
> How about:
>
> index 977fb79c1567..4d6105c07ac0 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> @@ -735,7 +735,7 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
> {
> struct pci_epf_test *epf_test = epf_get_drvdata(epf);
> struct pci_epf_header *header = epf->header;
> - const struct pci_epc_features *epc_features;
> + const struct pci_epc_features *epc_features = epf_test->epc_features;
> struct pci_epc *epc = epf->epc;
> struct device *dev = &epf->dev;
> bool linkup_notifier = false;
> @@ -743,12 +743,6 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
> bool msi_capable = true;
> int ret;
>
> - epc_features = pci_epc_get_features(epc, epf->func_no, epf->vfunc_no);
> - if (epc_features) {
> - msix_capable = epc_features->msix_capable;
> - msi_capable = epc_features->msi_capable;
> - }
> -
> if (epf->vfunc_no <= 1) {
> ret = pci_epc_write_header(epc, epf->func_no, epf->vfunc_no, header);
> if (ret) {
> @@ -761,6 +755,7 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
> if (ret)
> return ret;
>
> + msi_capable = epc_features->msi_capable;
> if (msi_capable) {
> ret = pci_epc_set_msi(epc, epf->func_no, epf->vfunc_no,
> epf->msi_interrupts);
> @@ -770,6 +765,7 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
> }
> }
>
> + msix_capable = epc_features->msix_capable;
> if (msix_capable) {
> ret = pci_epc_set_msix(epc, epf->func_no, epf->vfunc_no,
> epf->msix_interrupts,
> @@ -814,11 +810,9 @@ static int pci_epf_test_alloc_space(struct pci_epf *epf)
> void *base;
> enum pci_barno test_reg_bar = epf_test->test_reg_bar;
> enum pci_barno bar;
> - const struct pci_epc_features *epc_features;
> + const struct pci_epc_features *epc_features = epf_test->epc_features;
> size_t test_reg_size;
>
> - epc_features = epf_test->epc_features;
> -
> test_reg_bar_size = ALIGN(sizeof(struct pci_epf_test_reg), 128);
>
> msix_capable = epc_features->msix_capable;
>
>
> Instead?
>
> That way, we assign msi_capable/msix_capable just before the if-statement
> where it is used. (Which matches how we already assign msix_capable just
> before the if-statement in pci_epf_test_alloc_space().)
>
Ok, if we go with this pattern, then pci_epf_test_set_bar() also needs to be
updated.
- Mani
--
மணிவண்ணன் சதாசிவம்
On Wed, Apr 17, 2024 at 07:54:56PM +0200, Niklas Cassel wrote:
> On Wed, Apr 17, 2024 at 07:49:45PM +0200, Niklas Cassel wrote:
> > On Wed, Apr 17, 2024 at 10:47:25PM +0530, Manivannan Sadhasivam wrote:
> > > Instead of getting the epc_features from pci_epc_get_features() API, use
> > > the cached pci_epf_test::epc_features value to avoid the NULL check. Since
> > > the NULL check is already performed in pci_epf_test_bind(), having one more
> > > check in pci_epf_test_core_init() is redundant and it is not possible to
> > > hit the NULL pointer dereference. This also leads to the following smatch
> > > warning:
> > >
> > > drivers/pci/endpoint/functions/pci-epf-test.c:784 pci_epf_test_core_init()
> > > error: we previously assumed 'epc_features' could be null (see line 747)
> > >
> > > Reported-by: Dan Carpenter <[email protected]>
> > > Closes: https://lore.kernel.org/linux-pci/[email protected]/
> > > Signed-off-by: Manivannan Sadhasivam <[email protected]>
> >
> > I think you forgot:
> > Fixes: a01e7214bef9 ("PCI: endpoint: Remove "core_init_notifier" flag")
> >
> >
> > > ---
> > > drivers/pci/endpoint/functions/pci-epf-test.c | 9 ++++-----
> > > 1 file changed, 4 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> > > index 977fb79c1567..0d28f413cb07 100644
> > > --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> > > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> > > @@ -743,11 +743,10 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
> > > bool msi_capable = true;
> > > int ret;
> > >
> > > - epc_features = pci_epc_get_features(epc, epf->func_no, epf->vfunc_no);
> > > - if (epc_features) {
> > > - msix_capable = epc_features->msix_capable;
> > > - msi_capable = epc_features->msi_capable;
> > > - }
> > > + epc_features = epf_test->epc_features;
> >
> > How about:
> >
> > index 977fb79c1567..4d6105c07ac0 100644
> > --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> > @@ -735,7 +735,7 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
> > {
> > struct pci_epf_test *epf_test = epf_get_drvdata(epf);
> > struct pci_epf_header *header = epf->header;
> > - const struct pci_epc_features *epc_features;
> > + const struct pci_epc_features *epc_features = epf_test->epc_features;
> > struct pci_epc *epc = epf->epc;
> > struct device *dev = &epf->dev;
> > bool linkup_notifier = false;
> > @@ -743,12 +743,6 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
> > bool msi_capable = true;
> > int ret;
> >
> > - epc_features = pci_epc_get_features(epc, epf->func_no, epf->vfunc_no);
> > - if (epc_features) {
> > - msix_capable = epc_features->msix_capable;
> > - msi_capable = epc_features->msi_capable;
> > - }
> > -
> > if (epf->vfunc_no <= 1) {
> > ret = pci_epc_write_header(epc, epf->func_no, epf->vfunc_no, header);
> > if (ret) {
> > @@ -761,6 +755,7 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
> > if (ret)
> > return ret;
> >
> > + msi_capable = epc_features->msi_capable;
> > if (msi_capable) {
> > ret = pci_epc_set_msi(epc, epf->func_no, epf->vfunc_no,
> > epf->msi_interrupts);
> > @@ -770,6 +765,7 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
> > }
> > }
> >
> > + msix_capable = epc_features->msix_capable;
> > if (msix_capable) {
> > ret = pci_epc_set_msix(epc, epf->func_no, epf->vfunc_no,
> > epf->msix_interrupts,
> > @@ -814,11 +810,9 @@ static int pci_epf_test_alloc_space(struct pci_epf *epf)
> > void *base;
> > enum pci_barno test_reg_bar = epf_test->test_reg_bar;
> > enum pci_barno bar;
> > - const struct pci_epc_features *epc_features;
> > + const struct pci_epc_features *epc_features = epf_test->epc_features;
> > size_t test_reg_size;
> >
> > - epc_features = epf_test->epc_features;
> > -
> > test_reg_bar_size = ALIGN(sizeof(struct pci_epf_test_reg), 128);
> >
> > msix_capable = epc_features->msix_capable;
> >
> >
> > Instead?
> >
> > That way, we assign msi_capable/msix_capable just before the if-statement
> > where it is used. (Which matches how we already assign msix_capable just
> > before the if-statement in pci_epf_test_alloc_space().)
>
> ...or just kill the local variables:
> bool msi_capable/msix_capable in pci_epf_test_core_init(), and
> bool msix_capable pci_epf_test_alloc_space()
> and just do:
>
> if (epc_features->msix_capable) / if (epc_features->msi_capable)
>
> directly?
>
Yeah, that will also work.
- Mani
--
மணிவண்ணன் சதாசிவம்
On Thu, Apr 18, 2024 at 11:13:19AM +0530, Manivannan Sadhasivam wrote:
> On Wed, Apr 17, 2024 at 07:49:45PM +0200, Niklas Cassel wrote:
> > On Wed, Apr 17, 2024 at 10:47:25PM +0530, Manivannan Sadhasivam wrote:
> > > Instead of getting the epc_features from pci_epc_get_features() API, use
> > > the cached pci_epf_test::epc_features value to avoid the NULL check. Since
> > > the NULL check is already performed in pci_epf_test_bind(), having one more
> > > check in pci_epf_test_core_init() is redundant and it is not possible to
> > > hit the NULL pointer dereference. This also leads to the following smatch
> > > warning:
> > >
> > > drivers/pci/endpoint/functions/pci-epf-test.c:784 pci_epf_test_core_init()
> > > error: we previously assumed 'epc_features' could be null (see line 747)
> > >
> > > Reported-by: Dan Carpenter <[email protected]>
> > > Closes: https://lore.kernel.org/linux-pci/[email protected]/
> > > Signed-off-by: Manivannan Sadhasivam <[email protected]>
> >
> > I think you forgot:
> > Fixes: a01e7214bef9 ("PCI: endpoint: Remove "core_init_notifier" flag")
> >
>
> No, that's not the correct fixes tag I suppose. This redudant check is
> introduced by commit, 5e50ee27d4a5 ("PCI: pci-epf-test: Add support to defer
> core initialization") and this commit removes the redundant check (fixing smatch
> warning is a side effect). So if the fixes tag needs to be added, then this
> commit should be referenced.
Well, you have a Closes: tag that links to a bug report about a smatch
warning that was introduced with 5e50ee27d4a5 ("PCI: pci-epf-test: Add
support to defer core initialization").
So if you want to reference another commit, then you should probably
drop the Closes: tag.
>
> >
> > > ---
> > > drivers/pci/endpoint/functions/pci-epf-test.c | 9 ++++-----
> > > 1 file changed, 4 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> > > index 977fb79c1567..0d28f413cb07 100644
> > > --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> > > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> > > @@ -743,11 +743,10 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
> > > bool msi_capable = true;
> > > int ret;
> > >
> > > - epc_features = pci_epc_get_features(epc, epf->func_no, epf->vfunc_no);
> > > - if (epc_features) {
> > > - msix_capable = epc_features->msix_capable;
> > > - msi_capable = epc_features->msi_capable;
> > > - }
> > > + epc_features = epf_test->epc_features;
> >
> > How about:
> >
> > index 977fb79c1567..4d6105c07ac0 100644
> > --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> > @@ -735,7 +735,7 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
> > {
> > struct pci_epf_test *epf_test = epf_get_drvdata(epf);
> > struct pci_epf_header *header = epf->header;
> > - const struct pci_epc_features *epc_features;
> > + const struct pci_epc_features *epc_features = epf_test->epc_features;
> > struct pci_epc *epc = epf->epc;
> > struct device *dev = &epf->dev;
> > bool linkup_notifier = false;
> > @@ -743,12 +743,6 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
> > bool msi_capable = true;
> > int ret;
> >
> > - epc_features = pci_epc_get_features(epc, epf->func_no, epf->vfunc_no);
> > - if (epc_features) {
> > - msix_capable = epc_features->msix_capable;
> > - msi_capable = epc_features->msi_capable;
> > - }
> > -
> > if (epf->vfunc_no <= 1) {
> > ret = pci_epc_write_header(epc, epf->func_no, epf->vfunc_no, header);
> > if (ret) {
> > @@ -761,6 +755,7 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
> > if (ret)
> > return ret;
> >
> > + msi_capable = epc_features->msi_capable;
> > if (msi_capable) {
> > ret = pci_epc_set_msi(epc, epf->func_no, epf->vfunc_no,
> > epf->msi_interrupts);
> > @@ -770,6 +765,7 @@ static int pci_epf_test_core_init(struct pci_epf *epf)
> > }
> > }
> >
> > + msix_capable = epc_features->msix_capable;
> > if (msix_capable) {
> > ret = pci_epc_set_msix(epc, epf->func_no, epf->vfunc_no,
> > epf->msix_interrupts,
> > @@ -814,11 +810,9 @@ static int pci_epf_test_alloc_space(struct pci_epf *epf)
> > void *base;
> > enum pci_barno test_reg_bar = epf_test->test_reg_bar;
> > enum pci_barno bar;
> > - const struct pci_epc_features *epc_features;
> > + const struct pci_epc_features *epc_features = epf_test->epc_features;
> > size_t test_reg_size;
> >
> > - epc_features = epf_test->epc_features;
> > -
> > test_reg_bar_size = ALIGN(sizeof(struct pci_epf_test_reg), 128);
> >
> > msix_capable = epc_features->msix_capable;
> >
> >
> > Instead?
> >
> > That way, we assign msi_capable/msix_capable just before the if-statement
> > where it is used. (Which matches how we already assign msix_capable just
> > before the if-statement in pci_epf_test_alloc_space().)
> >
>
> Ok, if we go with this pattern, then pci_epf_test_set_bar() also needs to be
> updated.
pci_epf_test_set_bar() ? I presume that you mean pci_epf_test_alloc_space().
How about a 1/2 patch that modifies pci_epf_test_core_init() and Closes: the
bug report, and a 2/2 patch that modifies pci_epf_test_alloc_space() ?
Kind regards,
Niklas
On Thu, Apr 18, 2024 at 08:46:47AM +0200, Niklas Cassel wrote:
> On Thu, Apr 18, 2024 at 11:13:19AM +0530, Manivannan Sadhasivam wrote:
> > On Wed, Apr 17, 2024 at 07:49:45PM +0200, Niklas Cassel wrote:
> > > On Wed, Apr 17, 2024 at 10:47:25PM +0530, Manivannan Sadhasivam wrote:
> > > > Instead of getting the epc_features from pci_epc_get_features() API, use
> > > > the cached pci_epf_test::epc_features value to avoid the NULL check. Since
> > > > the NULL check is already performed in pci_epf_test_bind(), having one more
> > > > check in pci_epf_test_core_init() is redundant and it is not possible to
> > > > hit the NULL pointer dereference. This also leads to the following smatch
> > > > warning:
> > > >
> > > > drivers/pci/endpoint/functions/pci-epf-test.c:784 pci_epf_test_core_init()
> > > > error: we previously assumed 'epc_features' could be null (see line 747)
> > > >
> > > > Reported-by: Dan Carpenter <[email protected]>
> > > > Closes: https://lore.kernel.org/linux-pci/[email protected]/
> > > > Signed-off-by: Manivannan Sadhasivam <[email protected]>
> > >
> > > I think you forgot:
> > > Fixes: a01e7214bef9 ("PCI: endpoint: Remove "core_init_notifier" flag")
> > >
> >
> > No, that's not the correct fixes tag I suppose. This redudant check is
> > introduced by commit, 5e50ee27d4a5 ("PCI: pci-epf-test: Add support to defer
> > core initialization") and this commit removes the redundant check (fixing smatch
> > warning is a side effect). So if the fixes tag needs to be added, then this
> > commit should be referenced.
>
> Well, you have a Closes: tag that links to a bug report about a smatch
> warning that was introduced with 5e50ee27d4a5 ("PCI: pci-epf-test: Add
> support to defer core initialization").
>
> So if you want to reference another commit, then you should probably
> drop the Closes: tag.
>
Then checkpatch will complain... But I think I can keep the two tags? One is for
fixing the redudant check and another is for the smatch warning reported.
>
> >
> > >
[...]
> > > That way, we assign msi_capable/msix_capable just before the if-statement
> > > where it is used. (Which matches how we already assign msix_capable just
> > > before the if-statement in pci_epf_test_alloc_space().)
> > >
> >
> > Ok, if we go with this pattern, then pci_epf_test_set_bar() also needs to be
> > updated.
>
> pci_epf_test_set_bar() ? I presume that you mean pci_epf_test_alloc_space().
>
Oops. I referred from an old branch.
> How about a 1/2 patch that modifies pci_epf_test_core_init() and Closes: the
> bug report, and a 2/2 patch that modifies pci_epf_test_alloc_space() ?
>
Yes, that's the plan.
- Mani
--
மணிவண்ணன் சதாசிவம்
On Thu, Apr 18, 2024 at 12:23:08PM +0530, Manivannan Sadhasivam wrote:
> On Thu, Apr 18, 2024 at 08:46:47AM +0200, Niklas Cassel wrote:
> > On Thu, Apr 18, 2024 at 11:13:19AM +0530, Manivannan Sadhasivam wrote:
> > > On Wed, Apr 17, 2024 at 07:49:45PM +0200, Niklas Cassel wrote:
> > > > On Wed, Apr 17, 2024 at 10:47:25PM +0530, Manivannan Sadhasivam wrote:
> > > > > Instead of getting the epc_features from pci_epc_get_features() API, use
> > > > > the cached pci_epf_test::epc_features value to avoid the NULL check. Since
> > > > > the NULL check is already performed in pci_epf_test_bind(), having one more
> > > > > check in pci_epf_test_core_init() is redundant and it is not possible to
> > > > > hit the NULL pointer dereference. This also leads to the following smatch
> > > > > warning:
> > > > >
> > > > > drivers/pci/endpoint/functions/pci-epf-test.c:784 pci_epf_test_core_init()
> > > > > error: we previously assumed 'epc_features' could be null (see line 747)
> > > > >
> > > > > Reported-by: Dan Carpenter <[email protected]>
> > > > > Closes: https://lore.kernel.org/linux-pci/[email protected]/
> > > > > Signed-off-by: Manivannan Sadhasivam <[email protected]>
> > > >
> > > > I think you forgot:
> > > > Fixes: a01e7214bef9 ("PCI: endpoint: Remove "core_init_notifier" flag")
> > > >
> > >
> > > No, that's not the correct fixes tag I suppose. This redudant check is
> > > introduced by commit, 5e50ee27d4a5 ("PCI: pci-epf-test: Add support to defer
> > > core initialization") and this commit removes the redundant check (fixing smatch
> > > warning is a side effect). So if the fixes tag needs to be added, then this
> > > commit should be referenced.
> >
> > Well, you have a Closes: tag that links to a bug report about a smatch
> > warning that was introduced with 5e50ee27d4a5 ("PCI: pci-epf-test: Add
> > support to defer core initialization").
> >
> > So if you want to reference another commit, then you should probably
> > drop the Closes: tag.
> >
>
> Then checkpatch will complain... But I think I can keep the two tags? One is for
> fixing the redudant check and another is for the smatch warning reported.
Yes, I think so too.
You can have Fixes: to the commit that introduced the redundant check,
since this was obviously not the correct thing to do, and then perhaps
just mention commit 5e50ee27d4a5 ("PCI: pci-epf-test: Add support to
defer core initialization") somewhere in the commit log.
Kind regards,
Niklas
On Thu, Apr 18, 2024 at 09:14:23AM +0200, Niklas Cassel wrote:
> On Thu, Apr 18, 2024 at 12:23:08PM +0530, Manivannan Sadhasivam wrote:
> > On Thu, Apr 18, 2024 at 08:46:47AM +0200, Niklas Cassel wrote:
> > > On Thu, Apr 18, 2024 at 11:13:19AM +0530, Manivannan Sadhasivam wrote:
> > > > On Wed, Apr 17, 2024 at 07:49:45PM +0200, Niklas Cassel wrote:
> > > > > On Wed, Apr 17, 2024 at 10:47:25PM +0530, Manivannan Sadhasivam wrote:
> > > > > > Instead of getting the epc_features from pci_epc_get_features() API, use
> > > > > > the cached pci_epf_test::epc_features value to avoid the NULL check. Since
> > > > > > the NULL check is already performed in pci_epf_test_bind(), having one more
> > > > > > check in pci_epf_test_core_init() is redundant and it is not possible to
> > > > > > hit the NULL pointer dereference. This also leads to the following smatch
> > > > > > warning:
> > > > > >
> > > > > > drivers/pci/endpoint/functions/pci-epf-test.c:784 pci_epf_test_core_init()
> > > > > > error: we previously assumed 'epc_features' could be null (see line 747)
> > > > > >
> > > > > > Reported-by: Dan Carpenter <[email protected]>
> > > > > > Closes: https://lore.kernel.org/linux-pci/[email protected]/
> > > > > > Signed-off-by: Manivannan Sadhasivam <[email protected]>
> > > > >
> > > > > I think you forgot:
> > > > > Fixes: a01e7214bef9 ("PCI: endpoint: Remove "core_init_notifier" flag")
> > > > >
> > > >
> > > > No, that's not the correct fixes tag I suppose. This redudant check is
> > > > introduced by commit, 5e50ee27d4a5 ("PCI: pci-epf-test: Add support to defer
> > > > core initialization") and this commit removes the redundant check (fixing smatch
> > > > warning is a side effect). So if the fixes tag needs to be added, then this
> > > > commit should be referenced.
> > >
> > > Well, you have a Closes: tag that links to a bug report about a smatch
> > > warning that was introduced with 5e50ee27d4a5 ("PCI: pci-epf-test: Add
> > > support to defer core initialization").
> > >
> > > So if you want to reference another commit, then you should probably
> > > drop the Closes: tag.
> > >
> >
> > Then checkpatch will complain... But I think I can keep the two tags? One is for
> > fixing the redudant check and another is for the smatch warning reported.
>
> Yes, I think so too.
>
> You can have Fixes: to the commit that introduced the redundant check,
That is 5e50ee27d4a5.
> since this was obviously not the correct thing to do, and then perhaps
> just mention commit 5e50ee27d4a5 ("PCI: pci-epf-test: Add support to
> defer core initialization") somewhere in the commit log.
You mean a01e7214bef9 here?
- Mani
--
மணிவண்ணன் சதாசிவம்
On Thu, Apr 18, 2024 at 01:00:23PM +0530, Manivannan Sadhasivam wrote:
> On Thu, Apr 18, 2024 at 09:14:23AM +0200, Niklas Cassel wrote:
> > On Thu, Apr 18, 2024 at 12:23:08PM +0530, Manivannan Sadhasivam wrote:
> > > On Thu, Apr 18, 2024 at 08:46:47AM +0200, Niklas Cassel wrote:
> > > > On Thu, Apr 18, 2024 at 11:13:19AM +0530, Manivannan Sadhasivam wrote:
> > > > > On Wed, Apr 17, 2024 at 07:49:45PM +0200, Niklas Cassel wrote:
> > > > > > On Wed, Apr 17, 2024 at 10:47:25PM +0530, Manivannan Sadhasivam wrote:
> > > > > > > Instead of getting the epc_features from pci_epc_get_features() API, use
> > > > > > > the cached pci_epf_test::epc_features value to avoid the NULL check. Since
> > > > > > > the NULL check is already performed in pci_epf_test_bind(), having one more
> > > > > > > check in pci_epf_test_core_init() is redundant and it is not possible to
> > > > > > > hit the NULL pointer dereference. This also leads to the following smatch
> > > > > > > warning:
> > > > > > >
> > > > > > > drivers/pci/endpoint/functions/pci-epf-test.c:784 pci_epf_test_core_init()
> > > > > > > error: we previously assumed 'epc_features' could be null (see line 747)
> > > > > > >
> > > > > > > Reported-by: Dan Carpenter <[email protected]>
> > > > > > > Closes: https://lore.kernel.org/linux-pci/[email protected]/
> > > > > > > Signed-off-by: Manivannan Sadhasivam <[email protected]>
> > > > > >
> > > > > > I think you forgot:
> > > > > > Fixes: a01e7214bef9 ("PCI: endpoint: Remove "core_init_notifier" flag")
> > > > > >
> > > > >
> > > > > No, that's not the correct fixes tag I suppose. This redudant check is
> > > > > introduced by commit, 5e50ee27d4a5 ("PCI: pci-epf-test: Add support to defer
> > > > > core initialization") and this commit removes the redundant check (fixing smatch
> > > > > warning is a side effect). So if the fixes tag needs to be added, then this
> > > > > commit should be referenced.
> > > >
> > > > Well, you have a Closes: tag that links to a bug report about a smatch
> > > > warning that was introduced with 5e50ee27d4a5 ("PCI: pci-epf-test: Add
> > > > support to defer core initialization").
> > > >
> > > > So if you want to reference another commit, then you should probably
> > > > drop the Closes: tag.
> > > >
> > >
> > > Then checkpatch will complain... But I think I can keep the two tags? One is for
> > > fixing the redudant check and another is for the smatch warning reported.
> >
> > Yes, I think so too.
> >
> > You can have Fixes: to the commit that introduced the redundant check,
>
> That is 5e50ee27d4a5.
Yes :)
>
> > since this was obviously not the correct thing to do, and then perhaps
> > just mention commit 5e50ee27d4a5 ("PCI: pci-epf-test: Add support to
> > defer core initialization") somewhere in the commit log.
>
> You mean a01e7214bef9 here?
Yes :)
(I copied the wrong SHA1 here...)
Kind regards,
Niklas