Hi all, This series attempts to remove explicit mmiowb() calls from driver code, instead adding it to spin_unlock() for architectures that require it. The infamous "PowerPC trick" was found to be flawed, so a correct but probably slower version is made generic for architectures wishing to use it. I've ported RISC-V over to this interface, and hooked up PowerPC to the generic infrastructure but with their existing implementation. Other architectures that require a definition for mmiowb() now have it unconditionally called from their spin_unlock() code. If this is deemed to be expensive, they should be able to do something similar to RISC-V. I used coccinelle to remove the vast majority of the users, and the trivial spatch invocation is included in the commit message of that patch. I've also *build-tested* this for RISC-V, ia64, mips64, sh, powerpc64 and arm64. This is based on a couple of other I/O-related series that I have pending: https://lkml.org/lkml/2019/2/22/484 https://lkml.org/lkml/2019/2/22/500 so I've pushed the whole lot out on a branch for your comfort and convenience: git://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git io Feedback welcome, Will Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Andrea Parri <andrea.parri@xxxxxxxxxxxxxxxxxxxx> Cc: Palmer Dabbelt <palmer@xxxxxxxxxx> Cc: Daniel Lustig <dlustig@xxxxxxxxxx> Cc: David Howells <dhowells@xxxxxxxxxx> Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: "Maciej W. Rozycki" <macro@xxxxxxxxxxxxxx> Cc: Paul Burton <paul.burton@xxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx> Cc: Rich Felker <dalias@xxxxxxxx> Cc: Tony Luck <tony.luck@xxxxxxxxx> --->8 Will Deacon (20): asm-generic/mmiowb: Add generic implementation of mmiowb() tracking arch: Use asm-generic header for asm/mmiowb.h mmiowb: Hook up mmiowb helpers to spinlocks and generic I/O accessors ARM: io: Remove useless definition of mmiowb() arm64: io: Remove useless definition of mmiowb() x86: io: Remove useless definition of mmiowb() nds32: io: Remove useless definition of mmiowb() m68k: io: Remove useless definition of mmiowb() sh: Add unconditional mmiowb() to arch_spin_unlock() mips: Add unconditional mmiowb() to arch_spin_unlock() ia64: Add unconditional mmiowb() to arch_spin_unlock() powerpc: mmiowb: Hook up mmwiob() implementation to asm-generic code riscv: mmiowb: Hook up mmwiob() implementation to asm-generic code Documentation: Kill all references to mmiowb() drivers: Remove useless trailing comments from mmiowb() invocations drivers: Remove explicit invocations of mmiowb() scsi: qla1280: Remove stale comment about mmiowb() i40iw: Redefine i40iw_mmiowb() to do nothing net: silan: sc92031: Remove stale comment about mmiowb() arch: Remove dummy mmiowb() definitions from arch code Documentation/driver-api/device-io.rst | 45 --------- Documentation/driver-api/pci/p2pdma.rst | 4 - Documentation/memory-barriers.txt | 103 +-------------------- arch/alpha/include/asm/Kbuild | 1 + arch/alpha/include/asm/io.h | 2 - arch/arc/include/asm/Kbuild | 1 + arch/arm/include/asm/Kbuild | 1 + arch/arm/include/asm/io.h | 2 - arch/arm64/include/asm/Kbuild | 1 + arch/arm64/include/asm/io.h | 2 - arch/c6x/include/asm/Kbuild | 1 + arch/csky/include/asm/Kbuild | 1 + arch/h8300/include/asm/Kbuild | 1 + arch/hexagon/include/asm/Kbuild | 1 + arch/hexagon/include/asm/io.h | 2 - arch/ia64/include/asm/io.h | 4 - arch/ia64/include/asm/mmiowb.h | 12 +++ arch/ia64/include/asm/spinlock.h | 2 + arch/m68k/include/asm/Kbuild | 1 + arch/m68k/include/asm/io_mm.h | 2 - arch/microblaze/include/asm/Kbuild | 1 + arch/mips/include/asm/io.h | 3 - arch/mips/include/asm/mmiowb.h | 11 +++ arch/mips/include/asm/spinlock.h | 15 +++ arch/nds32/include/asm/Kbuild | 1 + arch/nds32/include/asm/io.h | 2 - arch/nios2/include/asm/Kbuild | 1 + arch/openrisc/include/asm/Kbuild | 1 + arch/parisc/include/asm/Kbuild | 1 + arch/parisc/include/asm/io.h | 2 - arch/powerpc/Kconfig | 1 + arch/powerpc/include/asm/io.h | 33 +------ arch/powerpc/include/asm/mmiowb.h | 41 ++++++++ arch/powerpc/include/asm/spinlock.h | 17 ---- arch/riscv/Kconfig | 1 + arch/riscv/include/asm/io.h | 15 +-- arch/riscv/include/asm/mmiowb.h | 14 +++ arch/s390/include/asm/Kbuild | 1 + arch/sh/include/asm/io.h | 3 - arch/sh/include/asm/mmiowb.h | 12 +++ arch/sh/include/asm/spinlock-llsc.h | 2 + arch/sparc/include/asm/Kbuild | 1 + arch/sparc/include/asm/io_64.h | 2 - arch/um/include/asm/Kbuild | 1 + arch/unicore32/include/asm/Kbuild | 1 + arch/x86/include/asm/io.h | 2 - arch/xtensa/include/asm/Kbuild | 1 + drivers/crypto/cavium/nitrox/nitrox_reqmgr.c | 4 - drivers/dma/txx9dmac.c | 3 - drivers/firewire/ohci.c | 1 - drivers/gpu/drm/i915/intel_hdmi.c | 10 -- drivers/ide/tx4939ide.c | 2 - drivers/infiniband/hw/hfi1/chip.c | 3 - drivers/infiniband/hw/hfi1/pio.c | 1 - drivers/infiniband/hw/hns/hns_roce_hw_v1.c | 2 - drivers/infiniband/hw/i40iw/i40iw_osdep.h | 2 +- drivers/infiniband/hw/mlx4/qp.c | 6 -- drivers/infiniband/hw/mlx5/qp.c | 1 - drivers/infiniband/hw/mthca/mthca_cmd.c | 6 -- drivers/infiniband/hw/mthca/mthca_cq.c | 5 - drivers/infiniband/hw/mthca/mthca_qp.c | 17 ---- drivers/infiniband/hw/mthca/mthca_srq.c | 6 -- drivers/infiniband/hw/qedr/verbs.c | 12 --- drivers/infiniband/hw/qib/qib_iba6120.c | 4 - drivers/infiniband/hw/qib/qib_iba7220.c | 3 - drivers/infiniband/hw/qib/qib_iba7322.c | 3 - drivers/infiniband/hw/qib/qib_sd7220.c | 4 - drivers/media/pci/dt3155/dt3155.c | 8 -- drivers/memstick/host/jmb38x_ms.c | 4 - drivers/misc/ioc4.c | 2 - drivers/misc/mei/hw-me.c | 3 - drivers/misc/tifm_7xx1.c | 1 - drivers/mmc/host/alcor.c | 1 - drivers/mmc/host/sdhci.c | 13 --- drivers/mmc/host/tifm_sd.c | 3 - drivers/mmc/host/via-sdmmc.c | 10 -- drivers/mtd/nand/raw/r852.c | 2 - drivers/mtd/nand/raw/txx9ndfmc.c | 1 - drivers/net/ethernet/aeroflex/greth.c | 1 - drivers/net/ethernet/alacritech/slicoss.c | 4 - drivers/net/ethernet/amazon/ena/ena_com.c | 1 - drivers/net/ethernet/atheros/atlx/atl1.c | 1 - drivers/net/ethernet/atheros/atlx/atl2.c | 1 - drivers/net/ethernet/broadcom/bnx2.c | 4 - drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c | 2 - drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.h | 4 - .../net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c | 1 - drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c | 29 ------ drivers/net/ethernet/broadcom/bnx2x/bnx2x_sp.c | 1 - drivers/net/ethernet/broadcom/bnx2x/bnx2x_sriov.c | 2 - drivers/net/ethernet/broadcom/bnx2x/bnx2x_vfpf.c | 4 - drivers/net/ethernet/broadcom/bnxt/bnxt.c | 3 - drivers/net/ethernet/broadcom/tg3.c | 6 -- .../net/ethernet/cavium/liquidio/cn66xx_device.c | 10 -- .../net/ethernet/cavium/liquidio/octeon_device.c | 1 - drivers/net/ethernet/cavium/liquidio/octeon_droq.c | 4 - .../net/ethernet/cavium/liquidio/request_manager.c | 1 - drivers/net/ethernet/intel/e1000/e1000_main.c | 5 - drivers/net/ethernet/intel/e1000e/netdev.c | 7 -- drivers/net/ethernet/intel/fm10k/fm10k_iov.c | 2 - drivers/net/ethernet/intel/fm10k/fm10k_main.c | 5 - drivers/net/ethernet/intel/i40e/i40e_txrx.c | 5 - drivers/net/ethernet/intel/iavf/iavf_txrx.c | 5 - drivers/net/ethernet/intel/ice/ice_txrx.c | 5 - drivers/net/ethernet/intel/igb/igb_main.c | 5 - drivers/net/ethernet/intel/igbvf/netdev.c | 4 - drivers/net/ethernet/intel/igc/igc_main.c | 5 - drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 5 - drivers/net/ethernet/marvell/sky2.c | 4 - drivers/net/ethernet/mellanox/mlx4/catas.c | 4 - drivers/net/ethernet/mellanox/mlx4/cmd.c | 13 --- drivers/net/ethernet/mellanox/mlx5/core/cmd.c | 1 - drivers/net/ethernet/myricom/myri10ge/myri10ge.c | 2 - drivers/net/ethernet/neterion/s2io.c | 2 - drivers/net/ethernet/neterion/vxge/vxge-main.c | 5 - drivers/net/ethernet/neterion/vxge/vxge-traffic.c | 4 - drivers/net/ethernet/qlogic/qed/qed_int.c | 13 --- drivers/net/ethernet/qlogic/qed/qed_spq.c | 3 - drivers/net/ethernet/qlogic/qede/qede_ethtool.c | 8 -- drivers/net/ethernet/qlogic/qede/qede_fp.c | 8 -- drivers/net/ethernet/qlogic/qla3xxx.c | 1 - drivers/net/ethernet/qlogic/qlge/qlge.h | 1 - drivers/net/ethernet/qlogic/qlge/qlge_main.c | 1 - drivers/net/ethernet/realtek/r8169.c | 5 - drivers/net/ethernet/renesas/ravb_main.c | 9 -- drivers/net/ethernet/renesas/ravb_ptp.c | 3 - drivers/net/ethernet/renesas/sh_eth.c | 1 - drivers/net/ethernet/sfc/falcon/io.h | 2 - drivers/net/ethernet/sfc/io.h | 2 - drivers/net/ethernet/silan/sc92031.c | 15 --- drivers/net/ethernet/via/via-rhine.c | 3 - drivers/net/ethernet/wiznet/w5100.c | 6 -- drivers/net/ethernet/wiznet/w5300.c | 15 --- drivers/net/wireless/ath/ath5k/base.c | 4 - drivers/net/wireless/ath/ath5k/mac80211-ops.c | 2 - drivers/net/wireless/broadcom/b43/main.c | 7 -- drivers/net/wireless/broadcom/b43/sysfs.c | 1 - drivers/net/wireless/broadcom/b43legacy/ilt.c | 2 - drivers/net/wireless/broadcom/b43legacy/main.c | 20 ---- drivers/net/wireless/broadcom/b43legacy/phy.c | 1 - drivers/net/wireless/broadcom/b43legacy/pio.h | 1 - drivers/net/wireless/broadcom/b43legacy/radio.c | 4 - drivers/net/wireless/broadcom/b43legacy/sysfs.c | 1 - drivers/net/wireless/intel/iwlegacy/common.h | 7 -- drivers/net/wireless/intel/iwlwifi/pcie/trans.c | 1 - drivers/ntb/hw/idt/ntb_hw_idt.c | 7 -- drivers/ntb/test/ntb_perf.c | 3 - drivers/scsi/bfa/bfa.h | 3 +- drivers/scsi/bfa/bfa_hw_cb.c | 2 - drivers/scsi/bfa/bfa_hw_ct.c | 2 - drivers/scsi/bnx2fc/bnx2fc_hwi.c | 2 - drivers/scsi/bnx2i/bnx2i_hwi.c | 3 - drivers/scsi/megaraid/megaraid_sas_base.c | 1 - drivers/scsi/megaraid/megaraid_sas_fusion.c | 1 - drivers/scsi/mpt3sas/mpt3sas_base.c | 1 - drivers/scsi/qedf/qedf_io.c | 1 - drivers/scsi/qedi/qedi_fw.c | 1 - drivers/scsi/qla1280.c | 15 --- drivers/ssb/pci.c | 1 - drivers/ssb/pcmcia.c | 4 - drivers/staging/comedi/drivers/mite.c | 3 - drivers/staging/comedi/drivers/ni_660x.c | 2 - drivers/staging/comedi/drivers/ni_mio_common.c | 1 - drivers/staging/comedi/drivers/ni_pcidio.c | 2 - drivers/staging/comedi/drivers/ni_tio.c | 1 - drivers/staging/comedi/drivers/s626.c | 2 - drivers/tty/serial/men_z135_uart.c | 1 - drivers/tty/serial/serial_txx9.c | 1 - drivers/usb/early/xhci-dbc.c | 4 - drivers/usb/host/xhci-dbgcap.c | 2 - include/asm-generic/io.h | 3 +- include/asm-generic/mmiowb.h | 60 ++++++++++++ include/linux/qed/qed_if.h | 2 - include/linux/spinlock.h | 11 ++- kernel/Kconfig.locks | 3 + kernel/locking/spinlock.c | 5 + kernel/locking/spinlock_debug.c | 6 +- sound/soc/txx9/txx9aclc-ac97.c | 1 - 178 files changed, 226 insertions(+), 764 deletions(-) create mode 100644 arch/ia64/include/asm/mmiowb.h create mode 100644 arch/mips/include/asm/mmiowb.h create mode 100644 arch/powerpc/include/asm/mmiowb.h create mode 100644 arch/riscv/include/asm/mmiowb.h create mode 100644 arch/sh/include/asm/mmiowb.h create mode 100644 include/asm-generic/mmiowb.h -- 2.11.0
