Re: [PATCH 15/23] seq_file: switch over direct seq_read method calls to seq_read_iter

From: Jon Hunter
Date: Fri Jul 10 2020 - 08:55:40 EST


Hi Christoph,

On 07/07/2020 18:47, Christoph Hellwig wrote:
> Switch over all instances used directly as methods using these sed
> expressions:
>
> sed -i -e 's/\.read\(\s*=\s*\)seq_read/\.read_iter\1seq_read_iter/g'
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> Documentation/filesystems/seq_file.rst | 2 +-
> Documentation/process/clang-format.rst | 4 +-
> .../it_IT/process/clang-format.rst | 4 +-
> arch/arm/mm/ptdump_debugfs.c | 2 +-
> arch/arm64/kvm/vgic/vgic-debug.c | 2 +-
> arch/c6x/platforms/pll.c | 2 +-
> arch/mips/cavium-octeon/oct_ilm.c | 2 +-
> arch/mips/kernel/segment.c | 2 +-
> arch/mips/ralink/bootrom.c | 2 +-
> arch/powerpc/kvm/book3s_xive_native.c | 2 +-
> arch/powerpc/kvm/timing.c | 2 +-
> arch/powerpc/mm/ptdump/bats.c | 2 +-
> arch/powerpc/mm/ptdump/hashpagetable.c | 2 +-
> arch/powerpc/mm/ptdump/ptdump.c | 2 +-
> arch/powerpc/mm/ptdump/segment_regs.c | 2 +-
> arch/powerpc/platforms/cell/spufs/file.c | 8 ++--
> arch/powerpc/platforms/pseries/hvCall_inst.c | 2 +-
> arch/s390/kernel/diag.c | 2 +-
> arch/s390/mm/dump_pagetables.c | 2 +-
> arch/s390/pci/pci_debug.c | 2 +-
> arch/sh/mm/asids-debugfs.c | 2 +-
> arch/sh/mm/cache-debugfs.c | 2 +-
> arch/sh/mm/pmb.c | 2 +-
> arch/sh/mm/tlb-debugfs.c | 2 +-
> arch/x86/kernel/cpu/mce/severity.c | 2 +-
> arch/x86/mm/pat/memtype.c | 2 +-
> arch/x86/mm/pat/set_memory.c | 2 +-
> arch/x86/xen/p2m.c | 2 +-
> block/blk-mq-debugfs.c | 2 +-
> drivers/base/power/wakeup.c | 2 +-
> drivers/block/aoe/aoeblk.c | 2 +-
> drivers/block/drbd/drbd_debugfs.c | 10 ++---
> drivers/block/nbd.c | 4 +-
> drivers/block/pktcdvd.c | 2 +-
> drivers/block/rsxx/core.c | 4 +-
> drivers/bus/mvebu-mbus.c | 4 +-
> drivers/char/tpm/eventlog/common.c | 2 +-
> .../crypto/allwinner/sun8i-ce/sun8i-ce-core.c | 2 +-
> .../crypto/allwinner/sun8i-ss/sun8i-ss-core.c | 2 +-
> drivers/crypto/amlogic/amlogic-gxl-core.c | 2 +-
> drivers/crypto/caam/dpseci-debugfs.c | 2 +-
> drivers/crypto/cavium/zip/zip_main.c | 6 +--
> drivers/crypto/hisilicon/qm.c | 2 +-
> drivers/crypto/qat/qat_common/adf_cfg.c | 2 +-
> .../qat/qat_common/adf_transport_debug.c | 4 +-
> drivers/firmware/tegra/bpmp-debugfs.c | 2 +-
> drivers/gpio/gpiolib.c | 2 +-
> drivers/gpu/drm/amd/amdkfd/kfd_debugfs.c | 4 +-
> .../gpu/drm/arm/display/komeda/komeda_dev.c | 2 +-
> drivers/gpu/drm/arm/malidp_drv.c | 2 +-
> drivers/gpu/drm/armada/armada_debugfs.c | 2 +-
> drivers/gpu/drm/drm_debugfs.c | 6 +--
> drivers/gpu/drm/drm_debugfs_crc.c | 2 +-
> drivers/gpu/drm/drm_mipi_dbi.c | 2 +-
> .../drm/i915/display/intel_display_debugfs.c | 16 ++++----
> drivers/gpu/drm/i915/gt/debugfs_gt.h | 2 +-
> drivers/gpu/drm/i915/i915_debugfs_params.c | 12 +++---
> drivers/gpu/drm/msm/disp/dpu1/dpu_core_irq.c | 2 +-
> drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 4 +-
> drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 2 +-
> drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 4 +-
> drivers/gpu/drm/msm/msm_debugfs.c | 2 +-
> drivers/gpu/drm/nouveau/nouveau_debugfs.c | 2 +-
> drivers/gpu/drm/omapdrm/dss/dss.c | 2 +-
> drivers/gpu/host1x/debug.c | 4 +-
> drivers/gpu/vga/vga_switcheroo.c | 2 +-
> drivers/hid/hid-picolcd_debugfs.c | 2 +-
> drivers/hid/hid-wiimote-debug.c | 2 +-
> drivers/ide/ide-proc.c | 2 +-
> drivers/infiniband/hw/cxgb4/device.c | 4 +-
> drivers/infiniband/hw/qib/qib_debugfs.c | 2 +-
> drivers/infiniband/ulp/ipoib/ipoib_fs.c | 4 +-
> drivers/md/bcache/closure.c | 2 +-
> drivers/media/cec/core/cec-core.c | 2 +-
> drivers/media/pci/saa7164/saa7164-core.c | 2 +-
> drivers/memory/emif.c | 4 +-
> drivers/memory/tegra/tegra124-emc.c | 2 +-
> drivers/memory/tegra/tegra186-emc.c | 2 +-
> drivers/memory/tegra/tegra20-emc.c | 2 +-
> drivers/memory/tegra/tegra30-emc.c | 2 +-
> drivers/mfd/ab3100-core.c | 2 +-
> drivers/mfd/ab3100-otp.c | 2 +-
> drivers/mfd/ab8500-debugfs.c | 14 +++----
> drivers/mfd/tps65010.c | 2 +-
> drivers/misc/habanalabs/debugfs.c | 2 +-
> drivers/mmc/core/mmc_test.c | 2 +-
> drivers/mtd/mtdcore.c | 4 +-
> drivers/mtd/ubi/debug.c | 2 +-
> .../ethernet/chelsio/cxgb4/cxgb4_debugfs.c | 38 +++++++++----------
> drivers/net/ethernet/chelsio/cxgb4/l2t.c | 2 +-
> .../ethernet/chelsio/cxgb4vf/cxgb4vf_main.c | 8 ++--
> .../freescale/dpaa2/dpaa2-eth-debugfs.c | 6 +--
> .../net/ethernet/intel/fm10k/fm10k_debugfs.c | 2 +-
> .../marvell/octeontx2/af/rvu_debugfs.c | 2 +-
> drivers/net/wireless/ath/ath5k/debug.c | 2 +-
> drivers/net/wireless/ath/wil6210/debugfs.c | 14 +++----
> .../broadcom/brcm80211/brcmsmac/debug.c | 2 +-
> .../net/wireless/intel/iwlwifi/fw/debugfs.c | 2 +-
> .../net/wireless/intel/iwlwifi/pcie/trans.c | 2 +-
> .../wireless/mediatek/mt76/mt7603/debugfs.c | 2 +-
> .../wireless/mediatek/mt76/mt7615/debugfs.c | 2 +-
> .../wireless/mediatek/mt76/mt76x02_debugfs.c | 4 +-
> .../wireless/mediatek/mt76/mt7915/debugfs.c | 4 +-
> .../net/wireless/mediatek/mt7601u/debugfs.c | 4 +-
> drivers/net/wireless/realtek/rtlwifi/debug.c | 2 +-
> drivers/net/wireless/realtek/rtw88/debug.c | 4 +-
> drivers/net/wireless/rsi/rsi_91x_debugfs.c | 4 +-
> drivers/net/xen-netback/xenbus.c | 2 +-
> drivers/nvme/host/fabrics.c | 2 +-
> drivers/pci/controller/pci-tegra.c | 2 +-
> drivers/platform/x86/asus-wmi.c | 2 +-
> drivers/platform/x86/intel_pmc_core.c | 2 +-
> .../platform/x86/intel_telemetry_debugfs.c | 4 +-
> drivers/power/supply/da9030_battery.c | 2 +-
> drivers/pwm/core.c | 2 +-
> drivers/ras/cec.c | 2 +-
> drivers/ras/debugfs.c | 2 +-
> drivers/s390/block/dasd.c | 2 +-
> drivers/s390/cio/qdio_debug.c | 2 +-
> drivers/scsi/hisi_sas/hisi_sas_main.c | 32 ++++++++--------
> drivers/scsi/qedf/qedf_dbg.h | 2 +-
> drivers/scsi/qedi/qedi_dbg.h | 2 +-
> drivers/scsi/qla2xxx/qla_dfs.c | 12 +++---
> drivers/scsi/snic/snic_debugfs.c | 4 +-
> drivers/sh/intc/virq-debugfs.c | 2 +-
> drivers/soc/qcom/cmd-db.c | 2 +-
> drivers/soc/qcom/socinfo.c | 4 +-
> drivers/soc/ti/knav_dma.c | 2 +-
> drivers/soc/ti/knav_qmss_queue.c | 2 +-
> .../interface/vchiq_arm/vchiq_debugfs.c | 4 +-
> drivers/usb/chipidea/debug.c | 4 +-
> drivers/usb/dwc2/debugfs.c | 2 +-
> drivers/usb/dwc3/debugfs.c | 8 ++--
> drivers/usb/gadget/udc/lpc32xx_udc.c | 2 +-
> drivers/usb/gadget/udc/renesas_usb3.c | 2 +-
> drivers/usb/host/xhci-debugfs.c | 6 +--
> drivers/usb/mtu3/mtu3_debugfs.c | 8 ++--
> drivers/usb/musb/musb_debugfs.c | 4 +-
> drivers/visorbus/visorbus_main.c | 2 +-
> drivers/xen/xenfs/xensyms.c | 2 +-
> fs/debugfs/file.c | 4 +-
> fs/dlm/debug_fs.c | 8 ++--
> fs/gfs2/glock.c | 6 +--
> fs/nfsd/nfs4state.c | 4 +-
> fs/nfsd/nfsctl.c | 10 ++---
> fs/ocfs2/cluster/netdebug.c | 6 +--
> fs/ocfs2/dlm/dlmdebug.c | 2 +-
> fs/ocfs2/dlmglue.c | 2 +-
> fs/openpromfs/inode.c | 2 +-
> fs/orangefs/orangefs-debugfs.c | 2 +-
> fs/proc/array.c | 2 +-
> fs/proc/base.c | 24 ++++++------
> fs/proc/fd.c | 2 +-
> fs/proc/task_mmu.c | 8 ++--
> fs/proc/task_nommu.c | 2 +-
> fs/proc_namespace.c | 6 +--
> include/linux/seq_file.h | 4 +-
> kernel/bpf/inode.c | 2 +-
> kernel/fail_function.c | 2 +-
> kernel/gcov/fs.c | 2 +-
> kernel/irq/debugfs.c | 2 +-
> kernel/kcsan/debugfs.c | 2 +-
> kernel/sched/debug.c | 2 +-
> kernel/time/test_udelay.c | 2 +-
> kernel/trace/ftrace.c | 16 ++++----
> kernel/trace/trace.c | 20 +++++-----
> kernel/trace/trace_dynevent.c | 2 +-
> kernel/trace/trace_events.c | 10 ++---
> kernel/trace/trace_events_hist.c | 4 +-
> kernel/trace/trace_events_synth.c | 2 +-
> kernel/trace/trace_events_trigger.c | 2 +-
> kernel/trace/trace_kprobe.c | 4 +-
> kernel/trace/trace_printk.c | 2 +-
> kernel/trace/trace_stack.c | 4 +-
> kernel/trace/trace_stat.c | 2 +-
> kernel/trace/trace_uprobe.c | 4 +-
> lib/debugobjects.c | 2 +-
> lib/dynamic_debug.c | 2 +-
> lib/error-inject.c | 2 +-
> lib/kunit/debugfs.c | 2 +-
> mm/kmemleak.c | 2 +-
> net/6lowpan/debugfs.c | 2 +-
> net/batman-adv/debugfs.c | 4 +-
> net/bluetooth/6lowpan.c | 2 +-
> net/hsr/hsr_debugfs.c | 2 +-
> net/l2tp/l2tp_debugfs.c | 2 +-
> net/sunrpc/cache.c | 2 +-
> net/sunrpc/debugfs.c | 4 +-
> net/sunrpc/rpc_pipe.c | 2 +-
> security/apparmor/apparmorfs.c | 10 ++---
> security/integrity/ima/ima_fs.c | 6 +--
> security/selinux/selinuxfs.c | 2 +-
> security/smack/smackfs.c | 20 +++++-----
> 193 files changed, 375 insertions(+), 375 deletions(-)


Following this change, I have noticed that several debugfs entries can
no longer be read on some Tegra platforms. For example ...

$ sudo cat /sys/kernel/debug/usb/xhci/3530000.usb/event-ring/cycle
cat: /sys/kernel/debug/usb/xhci/3530000.usb/event-ring/cycle: Invalid
argument

$ sudo cat /sys/kernel/debug/emc/available_rates


cat: /sys/kernel/debug/emc/available_rates: Invalid argument

$ sudo cat /sys/kernel/debug/bpmp/debug/proc/testint
cat: /sys/kernel/debug/bpmp/debug/proc/testint: Invalid argument

$ sudo cat /sys/kernel/debug/pcie/ports


cat: /sys/kernel/debug/pcie/ports: Invalid argument

I have reverted the above drivers to use seq_read() instead of
seq_read_iter() and they work again. Have you seen any problems with this?

Cheers
Jon

--
nvpublic