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[47.54.130.67]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-5164585cf66sm170094531cf.30.2026.05.19.08.32.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 19 May 2026 08:32:38 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1wPMQv-0000000FCii-39HS; Tue, 19 May 2026 12:32:37 -0300 Date: Tue, 19 May 2026 12:32:37 -0300 From: Jason Gunthorpe To: Leon Romanovsky Cc: Saeed Mahameed , Tariq Toukan , Mark Bloch , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH mlx5-next] net/mlx5: Consolidate UAR index to PFN helpers Message-ID: <20260519153237.GN7702@ziepe.ca> References: <20260519-mlx5-uar-index-v1-1-1027ae724bff@nvidia.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260519-mlx5-uar-index-v1-1-1027ae724bff@nvidia.com> On Tue, May 19, 2026 at 06:08:18PM +0300, Leon Romanovsky wrote: > From: Leon Romanovsky > > mlx5_core's uar2pfn() and mlx5_ib's uar_index2pfn() compute the same > value via slightly different idioms. Given: > > MLX5_ADAPTER_PAGE_SHIFT = 12 > MLX5_UARS_IN_PAGE = PAGE_SIZE / MLX5_ADAPTER_PAGE_SIZE > = 1 << (PAGE_SHIFT - 12) > > when uar_4k is set, uar2pfn()'s "index >> (PAGE_SHIFT - 12)" reduces to > "index / MLX5_UARS_IN_PAGE", which is exactly what uar_index2pfn() does. > When uar_4k is clear, both fall through to the identity case. The same > arithmetic is also open-coded a third time in uar_index2paddress(), which > just multiplies the result by PAGE_SIZE. > > The duplication is historical: uar_index2pfn() landed with the original > mlx5_ib driver in 2013 (e126ba97dba9), uar2pfn() was added in 2017 > (a6d51b68611e) when the bfreg allocator moved into mlx5_core, and no > shared header ever exposed the helper. The two were last touched in > parallel by aa8106f137b9 ("net/mlx5: Add explicit bar address field"), > confirming they are meant to behave identically. > > Replace all three local copies with two static inlines in > include/linux/mlx5/driver.h returning phys_addr_t, which is the > appropriate type for a value that subsequently feeds ioremap*() and > rdma_user_mmap_io(). No functional change. > > Signed-off-by: Leon Romanovsky > --- > mlx5_core's uar2pfn() and mlx5_ib's uar_index2pfn() compute the same > value via slightly different idioms. Let's consolidate them. > --- > drivers/infiniband/hw/mlx5/main.c | 25 ++----------------------- > drivers/net/ethernet/mellanox/mlx5/core/uar.c | 14 +------------- > include/linux/mlx5/driver.h | 16 ++++++++++++++++ > 3 files changed, 19 insertions(+), 36 deletions(-) > > diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c > index 428811fa805b..e61db29bc166 100644 > --- a/drivers/infiniband/hw/mlx5/main.c > +++ b/drivers/infiniband/hw/mlx5/main.c > @@ -2373,27 +2373,6 @@ static void mlx5_ib_dealloc_ucontext(struct ib_ucontext *ibcontext) > } > } > > -static phys_addr_t uar_index2pfn(struct mlx5_ib_dev *dev, > - int uar_idx) > -{ > - int fw_uars_per_page; > - > - fw_uars_per_page = MLX5_CAP_GEN(dev->mdev, uar_4k) ? MLX5_UARS_IN_PAGE : 1; > - > - return (dev->mdev->bar_addr >> PAGE_SHIFT) + uar_idx / fw_uars_per_page; > -} > - > -static u64 uar_index2paddress(struct mlx5_ib_dev *dev, > - int uar_idx) > -{ > - unsigned int fw_uars_per_page; > - > - fw_uars_per_page = MLX5_CAP_GEN(dev->mdev, uar_4k) ? > - MLX5_UARS_IN_PAGE : 1; > - > - return (dev->mdev->bar_addr + (uar_idx / fw_uars_per_page) * PAGE_SIZE); > -} > - > static int get_command(unsigned long offset) > { > return (offset >> MLX5_IB_MMAP_CMD_SHIFT) & MLX5_IB_MMAP_CMD_MASK; > @@ -2643,7 +2622,7 @@ static int uar_mmap(struct mlx5_ib_dev *dev, enum mlx5_ib_mmap_cmd cmd, > uar_index = bfregi->sys_pages[idx]; > } > > - pfn = uar_index2pfn(dev, uar_index); > + pfn = mlx5_uar_index_to_pfn(dev->mdev, uar_index); > mlx5_ib_dbg(dev, "uar idx 0x%lx, pfn %pa\n", idx, &pfn); > > err = rdma_user_mmap_io(&context->ibucontext, vma, pfn, PAGE_SIZE, > @@ -4327,7 +4306,7 @@ alloc_uar_entry(struct mlx5_ib_ucontext *c, > goto end; > > entry->page_idx = uar_index; > - entry->address = uar_index2paddress(dev, uar_index); > + entry->address = mlx5_uar_index_to_paddr(dev->mdev, uar_index); > if (alloc_type == MLX5_IB_UAPI_UAR_ALLOC_TYPE_BF) > entry->mmap_flag = MLX5_IB_MMAP_TYPE_UAR_WC; > else > diff --git a/drivers/net/ethernet/mellanox/mlx5/core/uar.c b/drivers/net/ethernet/mellanox/mlx5/core/uar.c > index 1513112ecec8..a85d8fed1546 100644 > --- a/drivers/net/ethernet/mellanox/mlx5/core/uar.c > +++ b/drivers/net/ethernet/mellanox/mlx5/core/uar.c > @@ -66,18 +66,6 @@ static int uars_per_sys_page(struct mlx5_core_dev *mdev) > return 1; > } > > -static u64 uar2pfn(struct mlx5_core_dev *mdev, u32 index) > -{ > - u32 system_page_index; > - > - if (MLX5_CAP_GEN(mdev, uar_4k)) > - system_page_index = index >> (PAGE_SHIFT - MLX5_ADAPTER_PAGE_SHIFT); > - else > - system_page_index = index; > - > - return (mdev->bar_addr >> PAGE_SHIFT) + system_page_index; > -} > - > static void up_rel_func(struct kref *kref) > { > struct mlx5_uars_page *up = container_of(kref, struct mlx5_uars_page, ref_count); > @@ -132,7 +120,7 @@ static struct mlx5_uars_page *alloc_uars_page(struct mlx5_core_dev *mdev, > goto error1; > } > > - pfn = uar2pfn(mdev, up->index); > + pfn = mlx5_uar_index_to_pfn(mdev, up->index); > if (map_wc) { > up->map = ioremap_wc(pfn << PAGE_SHIFT, PAGE_SIZE); The only places using PFN here immediately shift it, this should be using mlx5_uar_index_to_paddr() > +static inline phys_addr_t mlx5_uar_index_to_pfn(struct mlx5_core_dev *mdev, > + u32 uar_idx) > +{ > + u32 fw_uars_per_page = MLX5_CAP_GEN(mdev, uar_4k) ? MLX5_UARS_IN_PAGE : 1; > + > + return (mdev->bar_addr >> PAGE_SHIFT) + uar_idx / fw_uars_per_page; > +} > + > +static inline phys_addr_t mlx5_uar_index_to_paddr(struct mlx5_core_dev *mdev, > + u32 uar_idx) > +{ > + u32 fw_uars_per_page = MLX5_CAP_GEN(mdev, uar_4k) ? MLX5_UARS_IN_PAGE : 1; > + > + return mdev->bar_addr + (uar_idx / fw_uars_per_page) * PAGE_SIZE; > +} Then there is only one caller of the pfn version in uar_mmap which can just be written using phys and open code the >> PAGE_SHIFT No reason to duplicate this Jason