Re: [PATCH v4 8/8] linux/log2.h: Use roundup/dow_pow_two() on 64bit calculations
From: Bjorn Helgaas <helgaas@kernel.org>
Date: 2019-12-05 20:38:51
Also in:
linux-acpi, linux-devicetree, linux-iommu, linux-pci, linux-rdma, linux-rockchip, lkml, netdev
The subject contains a couple typos: it's missing "of" and it's missing the "n" on "down". On Tue, Dec 03, 2019 at 12:47:41PM +0100, Nicolas Saenz Julienne wrote:
The function now is safe to use while expecting a 64bit value. Use it where relevant.
Please include the function names ("roundup_pow_of_two()",
"rounddown_pow_of_two()") in the changelog so it is self-contained and
doesn't depend on the subject.
Signed-off-by: Nicolas Saenz Julienne <redacted>
With the nits above and below addressed, Acked-by: Bjorn Helgaas <bhelgaas@google.com> # drivers/pci
--- drivers/acpi/arm64/iort.c | 2 +- drivers/net/ethernet/mellanox/mlx4/en_clock.c | 3 ++- drivers/of/device.c | 3 ++- drivers/pci/controller/cadence/pcie-cadence-ep.c | 3 ++- drivers/pci/controller/cadence/pcie-cadence.c | 3 ++- drivers/pci/controller/pcie-brcmstb.c | 3 ++- drivers/pci/controller/pcie-rockchip-ep.c | 5 +++-- kernel/dma/direct.c | 2 +- 8 files changed, 15 insertions(+), 9 deletions(-)
quoted hunk ↗ jump to hunk
--- a/drivers/pci/controller/cadence/pcie-cadence-ep.c +++ b/drivers/pci/controller/cadence/pcie-cadence-ep.c@@ -10,6 +10,7 @@ #include <linux/platform_device.h> #include <linux/pm_runtime.h> #include <linux/sizes.h> +#include <linux/log2.h> #include "pcie-cadence.h"@@ -65,7 +66,7 @@ static int cdns_pcie_ep_set_bar(struct pci_epc *epc, u8 fn, * roundup_pow_of_two() returns an unsigned long, which is not suited * for 64bit values. */
Please remove the comment above since it no longer applies.
quoted hunk ↗ jump to hunk
- sz = 1ULL << fls64(sz - 1); + sz = roundup_pow_of_two(sz); aperture = ilog2(sz) - 7; /* 128B -> 0, 256B -> 1, 512B -> 2, ... */ if ((flags & PCI_BASE_ADDRESS_SPACE) == PCI_BASE_ADDRESS_SPACE_IO) {diff --git a/drivers/pci/controller/cadence/pcie-cadence.c b/drivers/pci/controller/cadence/pcie-cadence.c index cd795f6fc1e2..b1689f725b41 100644 --- a/drivers/pci/controller/cadence/pcie-cadence.c +++ b/drivers/pci/controller/cadence/pcie-cadence.c@@ -4,6 +4,7 @@ // Author: Cyrille Pitchen <cyrille.pitchen@free-electrons.com> #include <linux/kernel.h> +#include <linux/log2.h> #include "pcie-cadence.h"@@ -15,7 +16,7 @@ void cdns_pcie_set_outbound_region(struct cdns_pcie *pcie, u8 fn, * roundup_pow_of_two() returns an unsigned long, which is not suited * for 64bit values. */
Same here.
quoted hunk ↗ jump to hunk
- u64 sz = 1ULL << fls64(size - 1); + u64 sz = roundup_pow_of_two(size); int nbits = ilog2(sz); u32 addr0, addr1, desc0, desc1;--- a/drivers/pci/controller/pcie-rockchip-ep.c +++ b/drivers/pci/controller/pcie-rockchip-ep.c@@ -16,6 +16,7 @@ #include <linux/platform_device.h> #include <linux/pci-epf.h> #include <linux/sizes.h> +#include <linux/log2.h> #include "pcie-rockchip.h"@@ -70,7 +71,7 @@ static void rockchip_pcie_prog_ep_ob_atu(struct rockchip_pcie *rockchip, u8 fn, u32 r, u32 type, u64 cpu_addr, u64 pci_addr, size_t size) { - u64 sz = 1ULL << fls64(size - 1); + u64 sz = roundup_pow_of_two(size); int num_pass_bits = ilog2(sz); u32 addr0, addr1, desc0, desc1; bool is_nor_msg = (type == AXI_WRAPPER_NOR_MSG);@@ -176,7 +177,7 @@ static int rockchip_pcie_ep_set_bar(struct pci_epc *epc, u8 fn, * roundup_pow_of_two() returns an unsigned long, which is not suited * for 64bit values. */
And here.
quoted hunk ↗ jump to hunk
- sz = 1ULL << fls64(sz - 1); + sz = roundup_pow_of_two(sz); aperture = ilog2(sz) - 7; /* 128B -> 0, 256B -> 1, 512B -> 2, ... */ if ((flags & PCI_BASE_ADDRESS_SPACE) == PCI_BASE_ADDRESS_SPACE_IO) {diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 6af7ae83c4ad..056886c4efec 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c@@ -53,7 +53,7 @@ u64 dma_direct_get_required_mask(struct device *dev) { u64 max_dma = phys_to_dma_direct(dev, (max_pfn - 1) << PAGE_SHIFT); - return (1ULL << (fls64(max_dma) - 1)) * 2 - 1; + return rounddown_pow_of_two(max_dma) * 2 - 1;
Personally I would probably make this one a separate patch since it's qualitatively different than the others and it would avoid the slight awkwardness of the non-greppable "roundup/down_pow_of_two()" construction in the commit subject. But it's fine either way.
} static gfp_t __dma_direct_optimal_gfp_mask(struct device *dev, u64 dma_mask, -- 2.24.0
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