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 <dan.carpenter@xxxxxxxxxx> > > Closes: https://lore.kernel.org/linux-pci/024b5826-7180-4076-ae08-57d2584cca3f@moroto.mountain/ > > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > > 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
