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From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk,
	Jens Axboe <axboe@kernel.dk>,
	linux-fsdevel@vger.kernel.org
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Subject: [PATCH v2 0/8] cleanup llseek and splice
Date: Sat, 25 Jun 2022 13:01:07 +0200	[thread overview]
Message-ID: <20220625110115.39956-1-Jason@zx2c4.com> (raw)

The goal of this patchset is to enable splicing to internal pipes for
select chardevs where it makes sense to do so. In the process, however,
it was revealed that many regular files are problematic here. The key
insight is that splicing to internal pipes is okay so long as the splice
operation is rewindable. That means these devices need to be llseekable.

So the series first tries to make llseek a bit tamer, fixing up the
long-standing tension between llseek==NULL vs llseek==no_llseek vs
~FMODE_LSEEK.

With FMODE_LSEEK as good information, the series is able to adjust
internal pipe splicing to use that.

It is then able to remove no_llseek entirely, and make all checks use
FMODE_LSEEK and all invocations use vfs_llseek.

Along the way the series also fixes related bugs in ksmbd, dma-buf, and
vfio.

Jason A. Donenfeld (8):
  ksmbd: use vfs_llseek instead of dereferencing NULL
  fs: do not set no_llseek in fops
  fs: clear or set FMODE_LSEEK based on llseek function
  fs: check FMODE_LSEEK to control internal pipe splicing
  fs: do not compare against ->llseek
  fs: remove no_llseek
  dma-buf: remove useless FMODE_LSEEK flag
  vfio: do not set FMODE_LSEEK flag

 .../watchdog/convert_drivers_to_kernel_api.rst  |  1 -
 arch/parisc/kernel/perf.c                       |  1 -
 arch/powerpc/kernel/eeh.c                       |  4 ----
 arch/powerpc/platforms/52xx/mpc52xx_gpt.c       |  1 -
 arch/powerpc/platforms/cell/spufs/file.c        | 17 -----------------
 arch/powerpc/platforms/powernv/eeh-powernv.c    |  1 -
 arch/powerpc/platforms/pseries/dtl.c            |  1 -
 arch/s390/hypfs/hypfs_dbfs.c                    |  1 -
 arch/s390/hypfs/inode.c                         |  1 -
 arch/s390/kernel/debug.c                        |  1 -
 arch/s390/kernel/perf_cpum_cf.c                 |  1 -
 arch/s390/kernel/sysinfo.c                      |  1 -
 arch/s390/pci/pci_clp.c                         |  1 -
 arch/um/drivers/harddog_kern.c                  |  1 -
 arch/um/drivers/hostaudio_kern.c                |  2 --
 arch/x86/kernel/cpu/mce/dev-mcelog.c            |  1 -
 arch/x86/kernel/cpu/resctrl/pseudo_lock.c       |  1 -
 drivers/acpi/apei/erst-dbg.c                    |  1 -
 drivers/auxdisplay/charlcd.c                    |  1 -
 drivers/block/mtip32xx/mtip32xx.c               |  3 ---
 drivers/block/pktcdvd.c                         |  1 -
 drivers/bluetooth/hci_vhci.c                    |  1 -
 drivers/bus/moxtet.c                            |  2 --
 drivers/char/agp/frontend.c                     |  1 -
 drivers/char/applicom.c                         |  1 -
 drivers/char/ds1620.c                           |  1 -
 drivers/char/dtlk.c                             |  1 -
 drivers/char/hpet.c                             |  1 -
 drivers/char/ipmi/ipmi_watchdog.c               |  1 -
 drivers/char/pc8736x_gpio.c                     |  1 -
 drivers/char/pcmcia/cm4000_cs.c                 |  1 -
 drivers/char/pcmcia/cm4040_cs.c                 |  1 -
 drivers/char/pcmcia/scr24x_cs.c                 |  1 -
 drivers/char/ppdev.c                            |  1 -
 drivers/char/scx200_gpio.c                      |  1 -
 drivers/char/sonypi.c                           |  1 -
 drivers/char/tb0219.c                           |  1 -
 drivers/char/tpm/tpm-dev.c                      |  1 -
 drivers/char/tpm/tpm_vtpm_proxy.c               |  1 -
 drivers/char/tpm/tpmrm-dev.c                    |  1 -
 drivers/char/virtio_console.c                   |  1 -
 drivers/counter/counter-chrdev.c                |  1 -
 drivers/dma-buf/dma-buf.c                       |  1 -
 drivers/firewire/core-cdev.c                    |  1 -
 drivers/firmware/efi/capsule-loader.c           |  1 -
 drivers/firmware/efi/test/efi_test.c            |  1 -
 drivers/firmware/turris-mox-rwtm.c              |  1 -
 drivers/gnss/core.c                             |  1 -
 drivers/gpio/gpio-mockup.c                      |  1 -
 drivers/gpio/gpiolib-cdev.c                     |  1 -
 drivers/gpu/drm/drm_file.c                      |  4 +---
 drivers/gpu/drm/i915/i915_perf.c                |  1 -
 drivers/gpu/drm/msm/msm_perf.c                  |  1 -
 drivers/gpu/drm/msm/msm_rd.c                    |  1 -
 drivers/hid/uhid.c                              |  1 -
 drivers/hwmon/asus_atk0110.c                    |  1 -
 drivers/hwmon/fschmd.c                          |  1 -
 drivers/hwmon/w83793.c                          |  1 -
 drivers/hwtracing/coresight/coresight-etb10.c   |  1 -
 .../hwtracing/coresight/coresight-tmc-core.c    |  1 -
 drivers/hwtracing/intel_th/msu.c                |  1 -
 drivers/hwtracing/stm/core.c                    |  1 -
 drivers/i2c/i2c-dev.c                           |  1 -
 drivers/infiniband/core/ucma.c                  |  1 -
 drivers/infiniband/core/user_mad.c              |  2 --
 drivers/infiniband/core/uverbs_main.c           |  4 ----
 drivers/infiniband/hw/hfi1/fault.c              |  1 -
 drivers/infiniband/hw/mlx5/devx.c               |  2 --
 drivers/input/evdev.c                           |  1 -
 drivers/input/joydev.c                          |  1 -
 drivers/input/keyboard/applespi.c               |  1 -
 drivers/input/misc/uinput.c                     |  1 -
 drivers/input/serio/userio.c                    |  1 -
 drivers/isdn/capi/capi.c                        |  1 -
 drivers/isdn/mISDN/timerdev.c                   |  1 -
 drivers/leds/uleds.c                            |  1 -
 drivers/macintosh/adb.c                         |  1 -
 drivers/macintosh/smu.c                         |  1 -
 drivers/media/cec/core/cec-api.c                |  1 -
 drivers/media/mc/mc-devnode.c                   |  1 -
 drivers/media/rc/lirc_dev.c                     |  1 -
 drivers/media/usb/uvc/uvc_debugfs.c             |  1 -
 drivers/media/v4l2-core/v4l2-dev.c              |  1 -
 drivers/message/fusion/mptctl.c                 |  1 -
 drivers/misc/lis3lv02d/lis3lv02d.c              |  1 -
 drivers/misc/mei/main.c                         |  1 -
 drivers/misc/phantom.c                          |  1 -
 drivers/mmc/core/block.c                        |  1 -
 drivers/mtd/ubi/cdev.c                          |  2 --
 drivers/mtd/ubi/debug.c                         |  1 -
 drivers/net/netdevsim/fib.c                     |  1 -
 drivers/net/tap.c                               |  1 -
 drivers/net/tun.c                               |  1 -
 .../wireless/broadcom/brcm80211/brcmfmac/core.c |  1 -
 drivers/net/wireless/intel/iwlwifi/mvm/d3.c     |  1 -
 drivers/pinctrl/pinmux.c                        |  1 -
 drivers/platform/chrome/cros_ec_debugfs.c       |  1 -
 drivers/platform/chrome/wilco_ec/debugfs.c      |  1 -
 drivers/platform/chrome/wilco_ec/event.c        |  1 -
 drivers/platform/chrome/wilco_ec/telemetry.c    |  1 -
 .../platform/surface/surface_aggregator_cdev.c  |  1 -
 drivers/platform/surface/surface_dtx.c          |  1 -
 drivers/pps/pps.c                               |  1 -
 drivers/rtc/dev.c                               |  1 -
 drivers/rtc/rtc-m41t80.c                        |  1 -
 drivers/s390/char/fs3270.c                      |  1 -
 drivers/s390/char/sclp_ctl.c                    |  1 -
 drivers/s390/char/tape_char.c                   |  1 -
 drivers/s390/char/uvdevice.c                    |  1 -
 drivers/s390/char/vmcp.c                        |  1 -
 drivers/s390/char/vmlogrdr.c                    |  1 -
 drivers/s390/char/zcore.c                       |  2 --
 drivers/s390/cio/chsc_sch.c                     |  1 -
 drivers/s390/cio/css.c                          |  1 -
 drivers/s390/crypto/pkey_api.c                  |  1 -
 drivers/s390/crypto/zcrypt_api.c                |  1 -
 drivers/sbus/char/openprom.c                    |  1 -
 drivers/sbus/char/uctrl.c                       |  1 -
 drivers/scsi/sg.c                               |  1 -
 drivers/spi/spidev.c                            |  1 -
 drivers/staging/pi433/pi433_if.c                |  1 -
 .../intel/int340x_thermal/acpi_thermal_rel.c    |  1 -
 drivers/tty/tty_io.c                            |  3 ---
 drivers/usb/gadget/function/f_fs.c              |  2 --
 drivers/usb/gadget/legacy/inode.c               |  2 --
 drivers/usb/gadget/legacy/raw_gadget.c          |  1 -
 drivers/usb/gadget/udc/atmel_usba_udc.c         |  1 -
 drivers/usb/misc/ftdi-elan.c                    |  1 -
 drivers/usb/misc/ldusb.c                        |  1 -
 drivers/usb/mon/mon_bin.c                       |  1 -
 drivers/usb/mon/mon_stat.c                      |  1 -
 drivers/usb/mon/mon_text.c                      |  2 --
 drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c  |  2 --
 drivers/vfio/pci/mlx5/main.c                    |  2 --
 drivers/vfio/vfio.c                             |  2 +-
 drivers/watchdog/acquirewdt.c                   |  1 -
 drivers/watchdog/advantechwdt.c                 |  1 -
 drivers/watchdog/alim1535_wdt.c                 |  1 -
 drivers/watchdog/alim7101_wdt.c                 |  1 -
 drivers/watchdog/ar7_wdt.c                      |  1 -
 drivers/watchdog/at91rm9200_wdt.c               |  1 -
 drivers/watchdog/ath79_wdt.c                    |  1 -
 drivers/watchdog/cpu5wdt.c                      |  1 -
 drivers/watchdog/cpwd.c                         |  1 -
 drivers/watchdog/eurotechwdt.c                  |  1 -
 drivers/watchdog/gef_wdt.c                      |  1 -
 drivers/watchdog/geodewdt.c                     |  1 -
 drivers/watchdog/ib700wdt.c                     |  1 -
 drivers/watchdog/ibmasr.c                       |  1 -
 drivers/watchdog/indydog.c                      |  1 -
 drivers/watchdog/it8712f_wdt.c                  |  1 -
 drivers/watchdog/m54xx_wdt.c                    |  1 -
 drivers/watchdog/machzwd.c                      |  1 -
 drivers/watchdog/mixcomwd.c                     |  1 -
 drivers/watchdog/mtx-1_wdt.c                    |  1 -
 drivers/watchdog/nv_tco.c                       |  1 -
 drivers/watchdog/pc87413_wdt.c                  |  1 -
 drivers/watchdog/pcwd.c                         |  2 --
 drivers/watchdog/pcwd_pci.c                     |  2 --
 drivers/watchdog/pcwd_usb.c                     |  2 --
 drivers/watchdog/pika_wdt.c                     |  1 -
 drivers/watchdog/rc32434_wdt.c                  |  1 -
 drivers/watchdog/rdc321x_wdt.c                  |  1 -
 drivers/watchdog/riowd.c                        |  1 -
 drivers/watchdog/sa1100_wdt.c                   |  1 -
 drivers/watchdog/sb_wdog.c                      |  1 -
 drivers/watchdog/sbc60xxwdt.c                   |  1 -
 drivers/watchdog/sbc7240_wdt.c                  |  1 -
 drivers/watchdog/sbc8360.c                      |  1 -
 drivers/watchdog/sbc_epx_c3.c                   |  1 -
 drivers/watchdog/sbc_fitpc2_wdt.c               |  1 -
 drivers/watchdog/sc1200wdt.c                    |  1 -
 drivers/watchdog/sc520_wdt.c                    |  1 -
 drivers/watchdog/sch311x_wdt.c                  |  1 -
 drivers/watchdog/scx200_wdt.c                   |  1 -
 drivers/watchdog/smsc37b787_wdt.c               |  1 -
 drivers/watchdog/w83877f_wdt.c                  |  1 -
 drivers/watchdog/w83977f_wdt.c                  |  1 -
 drivers/watchdog/wafer5823wdt.c                 |  1 -
 drivers/watchdog/wdrtas.c                       |  2 --
 drivers/watchdog/wdt.c                          |  2 --
 drivers/watchdog/wdt285.c                       |  1 -
 drivers/watchdog/wdt977.c                       |  1 -
 drivers/watchdog/wdt_pci.c                      |  2 --
 drivers/xen/evtchn.c                            |  1 -
 drivers/xen/mcelog.c                            |  1 -
 drivers/xen/xenbus/xenbus_dev_frontend.c        |  1 -
 fs/coredump.c                                   |  4 ++--
 fs/debugfs/file.c                               |  1 -
 fs/dlm/debug_fs.c                               |  1 -
 fs/efivarfs/file.c                              |  1 -
 fs/file_table.c                                 |  2 ++
 fs/fsopen.c                                     |  1 -
 fs/fuse/control.c                               |  4 ----
 fs/fuse/dev.c                                   |  1 -
 fs/ksmbd/vfs.c                                  |  4 ++--
 fs/nsfs.c                                       |  1 -
 fs/open.c                                       |  2 ++
 fs/overlayfs/copy_up.c                          |  3 +--
 fs/pipe.c                                       |  1 -
 fs/read_write.c                                 | 16 +++-------------
 fs/splice.c                                     | 10 ++++------
 fs/ubifs/debug.c                                |  2 --
 include/linux/debugfs.h                         |  1 -
 include/linux/fs.h                              |  1 -
 kernel/bpf/bpf_iter.c                           |  1 -
 kernel/events/core.c                            |  1 -
 kernel/power/user.c                             |  1 -
 kernel/relay.c                                  |  1 -
 kernel/time/posix-clock.c                       |  1 -
 kernel/trace/trace.c                            |  3 ---
 mm/huge_memory.c                                |  1 -
 net/mac80211/rc80211_minstrel_ht_debugfs.c      |  2 --
 net/rfkill/core.c                               |  1 -
 net/socket.c                                    |  1 -
 net/sunrpc/cache.c                              |  4 ----
 net/sunrpc/rpc_pipe.c                           |  1 -
 scripts/coccinelle/api/stream_open.cocci        |  1 -
 sound/core/control.c                            |  1 -
 sound/core/oss/mixer_oss.c                      |  1 -
 sound/core/oss/pcm_oss.c                        |  1 -
 sound/core/pcm_native.c                         |  2 --
 sound/core/rawmidi.c                            |  1 -
 sound/core/seq/seq_clientmgr.c                  |  1 -
 sound/core/timer.c                              |  1 -
 sound/oss/dmasound/dmasound_core.c              |  3 ---
 virt/kvm/kvm_main.c                             |  1 -
 227 files changed, 18 insertions(+), 303 deletions(-)

-- 
2.35.1


             reply	other threads:[~2022-06-25 11:01 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-25 11:01 Jason A. Donenfeld [this message]
2022-06-25 11:01 ` [PATCH v2 1/8] ksmbd: use vfs_llseek instead of dereferencing NULL Jason A. Donenfeld
2022-06-25 22:15   ` Jason A. Donenfeld
2022-06-26  0:54     ` Steve French
2022-06-25 11:01 ` [PATCH v2 2/8] fs: do not set no_llseek in fops Jason A. Donenfeld
2022-06-25 11:01 ` [PATCH v2 3/8] fs: clear or set FMODE_LSEEK based on llseek function Jason A. Donenfeld
2022-06-25 13:07   ` Christoph Hellwig
2022-06-25 13:29     ` Al Viro
2022-06-25 13:39       ` Christoph Hellwig
2022-06-25 14:11         ` Al Viro
2022-06-25 11:01 ` [PATCH v2 4/8] fs: check FMODE_LSEEK to control internal pipe splicing Jason A. Donenfeld
2022-06-25 11:01 ` [PATCH v2 5/8] fs: do not compare against ->llseek Jason A. Donenfeld
2022-06-25 11:01 ` [PATCH v2 6/8] fs: remove no_llseek Jason A. Donenfeld
2022-06-25 13:10   ` Christoph Hellwig
2022-06-25 21:53     ` Jason A. Donenfeld
2022-06-25 11:01 ` [PATCH v2 7/8] dma-buf: remove useless FMODE_LSEEK flag Jason A. Donenfeld
2022-06-25 11:01   ` Jason A. Donenfeld
2022-06-27  9:08   ` Daniel Vetter
2022-06-27  9:08     ` Daniel Vetter
2022-06-27  9:38     ` Jason A. Donenfeld
2022-06-29 10:30     ` Sumit Semwal
2022-06-25 11:01 ` [PATCH v2 8/8] vfio: do not set " Jason A. Donenfeld
2022-06-27 20:07   ` Alex Williamson

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