From: Jason Wang <jasowang@redhat.com> To: "Zhu, Lingshan" <lingshan.zhu@intel.com> Cc: mst <mst@redhat.com>, virtualization <virtualization@lists.linux-foundation.org>, netdev <netdev@vger.kernel.org>, Dan Carpenter <dan.carpenter@oracle.com> Subject: Re: [PATCH] vDPA/ifcvf: assign nr_vring to the MSI vector of config_intr by default Date: Fri, 15 Apr 2022 13:51:16 +0800 [thread overview] Message-ID: <CACGkMEuLW_PypyiPVcNz-B5FWNpkzLWwzC0eaZsCih+PbNt3Cg@mail.gmail.com> (raw) In-Reply-To: <09a3613f-514b-c769-b8a0-25899b3d3159@intel.com> On Wed, Apr 13, 2022 at 5:16 PM Zhu, Lingshan <lingshan.zhu@intel.com> wrote: > > > > On 4/13/2022 4:14 PM, Jason Wang wrote: > > > > 在 2022/4/8 下午8:10, Zhu Lingshan 写道: > >> This commit assign struct ifcvf_hw.nr_vring to the MSIX vector of the > >> config interrupt by default in ifcvf_request_config_irq(). > >> ifcvf_hw.nr_vring is the most likely and the ideal case for > >> the device config interrupt handling, means every virtqueue has > >> an individual MSIX vector(0 ~ nr_vring - 1), and the config interrupt > >> has > >> its own MSIX vector(number nr_vring). > >> > >> This change can also make GCC W = 2 happy, silence the > >> "uninitialized" warning. > >> > >> Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com> > >> Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com> > >> --- > >> drivers/vdpa/ifcvf/ifcvf_main.c | 8 ++++---- > >> 1 file changed, 4 insertions(+), 4 deletions(-) > >> > >> diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c > >> b/drivers/vdpa/ifcvf/ifcvf_main.c > >> index 4366320fb68d..b500fb941dab 100644 > >> --- a/drivers/vdpa/ifcvf/ifcvf_main.c > >> +++ b/drivers/vdpa/ifcvf/ifcvf_main.c > >> @@ -290,13 +290,13 @@ static int ifcvf_request_config_irq(struct > >> ifcvf_adapter *adapter) > >> struct ifcvf_hw *vf = &adapter->vf; > >> int config_vector, ret; > >> + /* vector 0 ~ vf->nr_vring for vqs, num vf->nr_vring vector > >> for config interrupt */ > > > > > > The comment is right before this patch, but probably wrong for > > MSIX_VECTOR_DEV_SHARED. > This comment is for the case when every vq and config interrupt has its > own vector, how > about a better comment "The ideal the default case, vector 0 ~ > vf->nr_vring for vqs, num vf->nr_vring vector for config interrupt" Actually, I suggest to remove the comment since the code can explain itself. > > > > > >> + config_vector = vf->nr_vring; > >> + > >> + /* re-use the vqs vector */ > >> if (vf->msix_vector_status == MSIX_VECTOR_DEV_SHARED) > >> return 0; > >> - if (vf->msix_vector_status == MSIX_VECTOR_PER_VQ_AND_CONFIG) > >> - /* vector 0 ~ vf->nr_vring for vqs, num vf->nr_vring vector > >> for config interrupt */ > >> - config_vector = vf->nr_vring; > >> - > >> if (vf->msix_vector_status == MSIX_VECTOR_SHARED_VQ_AND_CONFIG) > >> /* vector 0 for vqs and 1 for config interrupt */ > >> config_vector = 1; > > > > > > Actually, I prefer to use if ... else ... here. > IMHO, if else may lead to mistakes. > > The code: > /* The ideal the default case, vector 0 ~ vf->nr_vring for vqs, > num vf->nr_vring vector for config interrupt */ > config_vector = vf->nr_vring; > > /* re-use the vqs vector */ > if (vf->msix_vector_status == MSIX_VECTOR_DEV_SHARED) > return 0; > > if (vf->msix_vector_status == MSIX_VECTOR_SHARED_VQ_AND_CONFIG) > /* vector 0 for vqs and 1 for config interrupt */ > config_vector = 1; > > > here by default config_vector = vf->nr_vring; > If msix_vector_status == MSIX_VECTOR_DEV_SHARED, it will reuse the dev > shared vector, means using the vector(value 0) for data-vqs. > If msix_vector_status == MSIX_VECTOR_SHARED_VQ_AND_CONFIG, it will use > vector=1(vector 0 for data-vqs). > > If we use if...else, it will be: > > /* re-use the vqs vector */ > if (vf->msix_vector_status == MSIX_VECTOR_DEV_SHARED) > return 0; > else > config_vector = 1; > > This looks like config_vector can only be 0(re-used vector for the > data-vqs, which is 0) or 1. It shadows the ideal and default case > config_vector = vf->nr_vring I meant something like if (DEV_SHARED) return 0; else if (SHARED_VQ_AND_CONFIG) config_vector = 1 else if (PER_VQ_AND_CONFIG) config_vector = vf->nr_vring else return -EINVAL; or using a switch here. (We get the warning because there's no way for the checker to know that msix_vector_status must be DEV_SHARED, SHARED_VQ_AND_CONFIG and PER_VQ_AND_CONFIG). Thanks > > Thanks, > Zhu Lingshan > > > > > Thanks > > > > >
WARNING: multiple messages have this Message-ID (diff)
From: Jason Wang <jasowang@redhat.com> To: "Zhu, Lingshan" <lingshan.zhu@intel.com> Cc: netdev <netdev@vger.kernel.org>, virtualization <virtualization@lists.linux-foundation.org>, Dan Carpenter <dan.carpenter@oracle.com>, mst <mst@redhat.com> Subject: Re: [PATCH] vDPA/ifcvf: assign nr_vring to the MSI vector of config_intr by default Date: Fri, 15 Apr 2022 13:51:16 +0800 [thread overview] Message-ID: <CACGkMEuLW_PypyiPVcNz-B5FWNpkzLWwzC0eaZsCih+PbNt3Cg@mail.gmail.com> (raw) In-Reply-To: <09a3613f-514b-c769-b8a0-25899b3d3159@intel.com> On Wed, Apr 13, 2022 at 5:16 PM Zhu, Lingshan <lingshan.zhu@intel.com> wrote: > > > > On 4/13/2022 4:14 PM, Jason Wang wrote: > > > > 在 2022/4/8 下午8:10, Zhu Lingshan 写道: > >> This commit assign struct ifcvf_hw.nr_vring to the MSIX vector of the > >> config interrupt by default in ifcvf_request_config_irq(). > >> ifcvf_hw.nr_vring is the most likely and the ideal case for > >> the device config interrupt handling, means every virtqueue has > >> an individual MSIX vector(0 ~ nr_vring - 1), and the config interrupt > >> has > >> its own MSIX vector(number nr_vring). > >> > >> This change can also make GCC W = 2 happy, silence the > >> "uninitialized" warning. > >> > >> Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com> > >> Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com> > >> --- > >> drivers/vdpa/ifcvf/ifcvf_main.c | 8 ++++---- > >> 1 file changed, 4 insertions(+), 4 deletions(-) > >> > >> diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c > >> b/drivers/vdpa/ifcvf/ifcvf_main.c > >> index 4366320fb68d..b500fb941dab 100644 > >> --- a/drivers/vdpa/ifcvf/ifcvf_main.c > >> +++ b/drivers/vdpa/ifcvf/ifcvf_main.c > >> @@ -290,13 +290,13 @@ static int ifcvf_request_config_irq(struct > >> ifcvf_adapter *adapter) > >> struct ifcvf_hw *vf = &adapter->vf; > >> int config_vector, ret; > >> + /* vector 0 ~ vf->nr_vring for vqs, num vf->nr_vring vector > >> for config interrupt */ > > > > > > The comment is right before this patch, but probably wrong for > > MSIX_VECTOR_DEV_SHARED. > This comment is for the case when every vq and config interrupt has its > own vector, how > about a better comment "The ideal the default case, vector 0 ~ > vf->nr_vring for vqs, num vf->nr_vring vector for config interrupt" Actually, I suggest to remove the comment since the code can explain itself. > > > > > >> + config_vector = vf->nr_vring; > >> + > >> + /* re-use the vqs vector */ > >> if (vf->msix_vector_status == MSIX_VECTOR_DEV_SHARED) > >> return 0; > >> - if (vf->msix_vector_status == MSIX_VECTOR_PER_VQ_AND_CONFIG) > >> - /* vector 0 ~ vf->nr_vring for vqs, num vf->nr_vring vector > >> for config interrupt */ > >> - config_vector = vf->nr_vring; > >> - > >> if (vf->msix_vector_status == MSIX_VECTOR_SHARED_VQ_AND_CONFIG) > >> /* vector 0 for vqs and 1 for config interrupt */ > >> config_vector = 1; > > > > > > Actually, I prefer to use if ... else ... here. > IMHO, if else may lead to mistakes. > > The code: > /* The ideal the default case, vector 0 ~ vf->nr_vring for vqs, > num vf->nr_vring vector for config interrupt */ > config_vector = vf->nr_vring; > > /* re-use the vqs vector */ > if (vf->msix_vector_status == MSIX_VECTOR_DEV_SHARED) > return 0; > > if (vf->msix_vector_status == MSIX_VECTOR_SHARED_VQ_AND_CONFIG) > /* vector 0 for vqs and 1 for config interrupt */ > config_vector = 1; > > > here by default config_vector = vf->nr_vring; > If msix_vector_status == MSIX_VECTOR_DEV_SHARED, it will reuse the dev > shared vector, means using the vector(value 0) for data-vqs. > If msix_vector_status == MSIX_VECTOR_SHARED_VQ_AND_CONFIG, it will use > vector=1(vector 0 for data-vqs). > > If we use if...else, it will be: > > /* re-use the vqs vector */ > if (vf->msix_vector_status == MSIX_VECTOR_DEV_SHARED) > return 0; > else > config_vector = 1; > > This looks like config_vector can only be 0(re-used vector for the > data-vqs, which is 0) or 1. It shadows the ideal and default case > config_vector = vf->nr_vring I meant something like if (DEV_SHARED) return 0; else if (SHARED_VQ_AND_CONFIG) config_vector = 1 else if (PER_VQ_AND_CONFIG) config_vector = vf->nr_vring else return -EINVAL; or using a switch here. (We get the warning because there's no way for the checker to know that msix_vector_status must be DEV_SHARED, SHARED_VQ_AND_CONFIG and PER_VQ_AND_CONFIG). Thanks > > Thanks, > Zhu Lingshan > > > > > Thanks > > > > > _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
next prev parent reply other threads:[~2022-04-15 5:51 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-04-08 12:10 [PATCH] vDPA/ifcvf: assign nr_vring to the MSI vector of config_intr by default Zhu Lingshan 2022-04-13 8:14 ` Jason Wang 2022-04-13 8:14 ` Jason Wang 2022-04-13 9:16 ` Zhu, Lingshan 2022-04-15 5:51 ` Jason Wang [this message] 2022-04-15 5:51 ` Jason Wang
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