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2024-02-15pwm: atmel: Change prototype of a helper to prepare further changesUwe Kleine-König
This prepares the driver for further changes that will make it harder to determine the pwm_chip from a given atmel_pwm_chip. To just not have to do that, rework atmel_pwm_enable_clk_if_on() to take a pwm_chip. Link: https://lore.kernel.org/r/c9a92f77760e401debfe0c9bfc086222f31fb3c4.1707900770.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: apple: Make use of devm_pwmchip_alloc() functionUwe Kleine-König
This prepares the pwm-apple driver to further changes of the pwm core outlined in the commit introducing devm_pwmchip_alloc(). There is no intended semantical change and the driver should behave as before. Link: https://lore.kernel.org/r/34cf20a82ca07bb4ec0578b193daa5caed37825e.1707900770.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: ab8500: Make use of devm_pwmchip_alloc() functionUwe Kleine-König
This prepares the pwm-ab8500 driver to further changes of the pwm core outlined in the commit introducing devm_pwmchip_alloc(). There is no intended semantical change and the driver should behave as before. Link: https://lore.kernel.org/r/9c952baafe7e53c482adf23215138724b61e376b.1707900770.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: ab8500: Introduce a local pwm_chip variable in .probe()Uwe Kleine-König
This simplifies converting the driver to pwmchip_alloc() as there is only a single code line left that makes use of struct ab8500_pwm_chip::chip. Link: https://lore.kernel.org/r/7fae4833b97728abc8bd400663fdd331c86a761b.1707900770.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: ab8500: Make use of pwmchip_parent() accessorUwe Kleine-König
struct pwm_chip::dev is about to change. To not have to touch this driver in the same commit as struct pwm_chip::dev, use the accessor function provided for exactly this purpose. Link: https://lore.kernel.org/r/24028d8d0add621a0c054235e6281a05a83d8fb4.1707900770.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: Provide pwmchip_alloc() function and a devm variant of itUwe Kleine-König
This function allocates a struct pwm_chip and driver data. Compared to the status quo the split into pwm_chip and driver data is new, otherwise it doesn't change anything relevant (yet). The intention is that after all drivers are switched to use this allocation function, its possible to add a struct device to struct pwm_chip to properly track the latter's lifetime without touching all drivers again. Proper lifetime tracking is a necessary precondition to introduce character device support for PWMs (that implements atomic setting and doesn't suffer from the sysfs overhead of the /sys/class/pwm userspace support). The new function pwmchip_priv() (obviously?) only works for chips allocated with pwmchip_alloc(). Link: https://lore.kernel.org/r/9577d6053a5a52536057dc8654ff567181c2da82.1707900770.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: Provide wrappers for storing and getting driver private dataUwe Kleine-König
These functions are useful to store and query driver private data depending on the pwm_chip. After struct pwm_chip got its own struct device, this can make use of dev_get_drvdata() and dev_set_drvdata() on that device. These functions are required already now to convert drivers to pwmchip_alloc() which must happen before changing pwm_chip::dev. Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> Link: https://lore.kernel.org/r/67514cdf29d29bd8b4ad8d44fac87f6ae6dca1e5.1707900770.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: Provide an inline function to get the parent device of a given chipUwe Kleine-König
Currently a pwm_chip stores in its struct device *dev member a pointer to the parent device. Preparing a change that embeds a full struct device in struct pwm_chip, this accessor function should be used in all drivers directly accessing chip->dev now. This way struct pwm_chip and this new function can be changed without having to touch all drivers in the same change set. Make use of this function in the framework's core sources. Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://lore.kernel.org/r/cc30090d2f9762bed9854a55612144bccc910781.1707900770.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: mediatek: add support for MT7988Rafał Miłecki
MT7988 uses new registers layout just like MT7981 but it supports 8 PWM interfaces. Signed-off-by: Rafał Miłecki <rafal@milecki.pl> Reviewed-by: Daniel Golle <daniel@makrotopia.org> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> Link: https://lore.kernel.org/r/20240214140454.6438-2-zajec5@gmail.com Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15dt-bindings: pwm: mediatek,mt2712: add compatible for MT7988Rafał Miłecki
MT7988 has on-SoC controller that can control up to 8 PWM interfaces. It differs from blocks on other SoCs (amount of PWMs & registers) so it needs its own compatible string. Signed-off-by: Rafał Miłecki <rafal@milecki.pl> Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> Link: https://lore.kernel.org/r/20240214140454.6438-1-zajec5@gmail.com Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: dwc: access driver_data using dev_get_drvdata()Raag Jadav
Now that we're setting driver_data using dev_set_drvdata(), we can use dev_get_drvdata() for accessing it. Signed-off-by: Raag Jadav <raag.jadav@intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20240212130247.9985-6-raag.jadav@intel.com Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15dt-bindings: atmel,hlcdc: convert pwm bindings to json-schemaDharma Balasubiramani
Convert device tree bindings for Atmel's HLCDC PWM controller to YAML format. Signed-off-by: Dharma Balasubiramani <dharma.b@microchip.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20240202001733.91455-3-dharma.b@microchip.com Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: imx27: Don't use pwm consumer APIUwe Kleine-König
Lowlevel driver callbacks are not supposed to use the consumer API functions. Currently this works, but with the upcoming locking changes this maybe results in dead locks. So directly access pwm->state. Link: https://lore.kernel.org/r/20240126101624.2056801-2-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: atmel: Don't use pwm consumer APIUwe Kleine-König
Lowlevel driver callbacks are not supposed to use the consumer API functions. Currently this works, but with the upcoming locking changes this probably results in dead locks. Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev> Link: https://lore.kernel.org/r/20240129085627.2386470-2-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: atmel-hlcdc: Don't use pwm consumer APIUwe Kleine-König
Lowlevel driver callbacks are not supposed to use the consumer API functions. Currently this works, but with the upcoming locking changes this probably results in dead locks. Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev> Link: https://lore.kernel.org/r/6e34607828b290cd64ca9f82df40872853069f07.1706269232.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: bcm2835: Drop write-only member of driver private dataUwe Kleine-König
Since commit fcc760729359 ("pwm: bcm2835: Allow PWM driver to be used in atomic context") struct bcm2835_pwm::dev is only assigned a value, but it's never used. So the dev member can just be dropped. Link: https://lore.kernel.org/r/20240129081029.2355612-2-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: Reorder symbols in core.cUwe Kleine-König
This moves the functions called by pwm consumers above the functions called by pwm providers. When character device support is added later this is hooked into the chip registration functions. As the needed callbacks are a kind of consumer and make use of the consumer functions, having this order is more natural and prevents having to add declarations for static functions. Also move the global variables for pwm tables to the respective functions to have them properly grouped. Link: https://lore.kernel.org/r/eed83de07bdfb69b5ceba0b9aed757ee612dea8f.1706182805.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15dt-bindings: pxa-pwm: Convert to YAMLDuje Mihanović
Convert the PXA PWM binding file from TXT to YAML. The original binding does not mention any clocks, but the PWM controller will not probe without a clock. Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Duje Mihanović <duje.mihanovic@skole.hr> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Link: https://lore.kernel.org/r/20240107-pxa-pwm-yaml-v3-1-92ac90911c3f@skole.hr Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: mediatek: Update kernel doc for struct pwm_mediatek_of_dataUwe Kleine-König
The struct never had a member called clk_freq. This fixes the W=1 warning: drivers/pwm/pwm-mediatek.c:60: warning: Excess struct member 'clk_freq' description in 'pwm_mediatek_chip' Fixes: efecdeb82f21 ("pwm: mediatek: Allocate the clks array dynamically") Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> Link: https://lore.kernel.org/r/20240125085649.1571268-2-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: Drop duplicate check against chip->npwm in of_pwm_xlate_with_flags()Uwe Kleine-König
args->args[0] is passed as parameter "index" to pwm_request_from_chip(). The latter function also checks for index >= npwm, so of_pwm_xlate_with_flags() doesn't need to do that. Link: https://lore.kernel.org/r/b06e445a6ed62a339add727eccb969a33d678386.1704835845.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: clps711x: Drop custom .of_xlate() callbackUwe Kleine-König
The default of_xlate callback (of_pwm_xlate_with_flags()) does everything the drivers expects from its .of_xlate() callback. So drop the custom implementation. Link: https://lore.kernel.org/r/f58336c298d536107de5cab6a57e19f957ab326c.1704835845.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: Let the of_xlate callbacks accept references without periodUwe Kleine-König
With this extension of_pwm_xlate_with_flags() is suitable to replace the custom xlate function of the pwm-clps711x driver. While touching these very similar functions align their implementations. Link: https://lore.kernel.org/r/127622315d07d9d419ae8e6373c7e5be7fab7a62.1704835845.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: Drop useless member .of_pwm_n_cells of struct pwm_chipUwe Kleine-König
Apart from the two of_xlate implementations this member is write-only. In the of_xlate functions of_pwm_xlate_with_flags() and of_pwm_single_xlate() it's more sensible to check for args->args_count because this is what is actually used in the device tree. Acked-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/53d8c545aa8f79a920358be9e72e382b3981bdc4.1704835845.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15pwm: dwc: use pm_sleep_ptr() macroRaag Jadav
Since we don't have runtime PM handles here, we should be using pm_sleep_ptr() macro, so that the compiler can discard it in case CONFIG_PM_SLEEP=n. Fixes: 30b5b066fa83 ("pwm: dwc: Use DEFINE_SIMPLE_DEV_PM_OPS for PM functions") Signed-off-by: Raag Jadav <raag.jadav@intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20240212130247.9985-2-raag.jadav@intel.com Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-07pwm: sti: Fix capture for st,pwm-num-chan < st,capture-num-chanUwe Kleine-König
The driver only used the number of pwm channels to set the pwm_chip's npwm member. The result is that if there are more capture channels than PWM channels specified in the device tree, only a part of the capture channel is usable. Fix that by passing the bigger channel count to the pwm framework. This makes it possible that the .apply() callback is called with .hwpwm >= pwm_num_devs, catch that case and return an error code. Fixes: c97267ae831d ("pwm: sti: Add PWM capture callback") Link: https://lore.kernel.org/r/20240204212043.2951852-2-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-04pwm: atmel-hlcdc: Fix clock imbalance related to suspend supportUwe Kleine-König
The suspend callback disables the periph clock when the PWM is enabled and resume reenables this clock if the PWM was disabled before. Judging from the code comment it's suspend that is wrong here. Fix accordingly. Fixes: f9bb9da7c09d ("pwm: atmel-hlcdc: Implement the suspend/resume hooks") Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev> Link: https://lore.kernel.org/r/b51ea92b0a45eff3dc83b08adefd43d930df996c.1706269232.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-01-21Linux 6.8-rc1v6.8-rc1Linus Torvalds
2024-01-21Merge tag 'bcachefs-2024-01-21' of https://evilpiepirate.org/git/bcachefsLinus Torvalds
Pull more bcachefs updates from Kent Overstreet: "Some fixes, Some refactoring, some minor features: - Assorted prep work for disk space accounting rewrite - BTREE_TRIGGER_ATOMIC: after combining our trigger callbacks, this makes our trigger context more explicit - A few fixes to avoid excessive transaction restarts on multithreaded workloads: fstests (in addition to ktest tests) are now checking slowpath counters, and that's shaking out a few bugs - Assorted tracepoint improvements - Starting to break up bcachefs_format.h and move on disk types so they're with the code they belong to; this will make room to start documenting the on disk format better. - A few minor fixes" * tag 'bcachefs-2024-01-21' of https://evilpiepirate.org/git/bcachefs: (46 commits) bcachefs: Improve inode_to_text() bcachefs: logged_ops_format.h bcachefs: reflink_format.h bcachefs; extents_format.h bcachefs: ec_format.h bcachefs: subvolume_format.h bcachefs: snapshot_format.h bcachefs: alloc_background_format.h bcachefs: xattr_format.h bcachefs: dirent_format.h bcachefs: inode_format.h bcachefs; quota_format.h bcachefs: sb-counters_format.h bcachefs: counters.c -> sb-counters.c bcachefs: comment bch_subvolume bcachefs: bch_snapshot::btime bcachefs: add missing __GFP_NOWARN bcachefs: opts->compression can now also be applied in the background bcachefs: Prep work for variable size btree node buffers bcachefs: grab s_umount only if snapshotting ...
2024-01-21Merge tag 'timers-core-2024-01-21' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer updates from Thomas Gleixner: "Updates for time and clocksources: - A fix for the idle and iowait time accounting vs CPU hotplug. The time is reset on CPU hotplug which makes the accumulated systemwide time jump backwards. - Assorted fixes and improvements for clocksource/event drivers" * tag 'timers-core-2024-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tick-sched: Fix idle and iowait sleeptime accounting vs CPU hotplug clocksource/drivers/ep93xx: Fix error handling during probe clocksource/drivers/cadence-ttc: Fix some kernel-doc warnings clocksource/drivers/timer-ti-dm: Fix make W=n kerneldoc warnings clocksource/timer-riscv: Add riscv_clock_shutdown callback dt-bindings: timer: Add StarFive JH8100 clint dt-bindings: timer: thead,c900-aclint-mtimer: separate mtime and mtimecmp regs
2024-01-21Merge tag 'powerpc-6.8-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux Pull powerpc fixes from Aneesh Kumar: - Increase default stack size to 32KB for Book3S Thanks to Michael Ellerman. * tag 'powerpc-6.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc/64s: Increase default stack size to 32KB
2024-01-21bcachefs: Improve inode_to_text()Kent Overstreet
Add line breaks - inode_to_text() is now much easier to read. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21bcachefs: logged_ops_format.hKent Overstreet
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21bcachefs: reflink_format.hKent Overstreet
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21bcachefs; extents_format.hKent Overstreet
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21bcachefs: ec_format.hKent Overstreet
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21bcachefs: subvolume_format.hKent Overstreet
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21bcachefs: snapshot_format.hKent Overstreet
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21bcachefs: alloc_background_format.hKent Overstreet
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21bcachefs: xattr_format.hKent Overstreet
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21bcachefs: dirent_format.hKent Overstreet
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21bcachefs: inode_format.hKent Overstreet
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21bcachefs; quota_format.hKent Overstreet
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21bcachefs: sb-counters_format.hKent Overstreet
bcachefs_format.h has gotten too big; let's do some organizing. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21bcachefs: counters.c -> sb-counters.cKent Overstreet
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21bcachefs: comment bch_subvolumeKent Overstreet
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21bcachefs: bch_snapshot::btimeKent Overstreet
Add a field to bch_snapshot for creation time; this will be important when we start exposing the snapshot tree to userspace. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21bcachefs: add missing __GFP_NOWARNKent Overstreet
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21bcachefs: opts->compression can now also be applied in the backgroundKent Overstreet
The "apply this compression method in the background" paths now use the compression option if background_compression is not set; this means that setting or changing the compression option will cause existing data to be compressed accordingly in the background. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21bcachefs: Prep work for variable size btree node buffersKent Overstreet
bcachefs btree nodes are big - typically 256k - and btree roots are pinned in memory. As we're now up to 18 btrees, we now have significant memory overhead in mostly empty btree roots. And in the future we're going to start enforcing that certain btree node boundaries exist, to solve lock contention issues - analagous to XFS's AGIs. Thus, we need to start allocating smaller btree node buffers when we can. This patch changes code that refers to the filesystem constant c->opts.btree_node_size to refer to the btree node buffer size - btree_buf_bytes() - where appropriate. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21bcachefs: grab s_umount only if snapshottingSu Yue
When I was testing mongodb over bcachefs with compression, there is a lockdep warning when snapshotting mongodb data volume. $ cat test.sh prog=bcachefs $prog subvolume create /mnt/data $prog subvolume create /mnt/data/snapshots while true;do $prog subvolume snapshot /mnt/data /mnt/data/snapshots/$(date +%s) sleep 1s done $ cat /etc/mongodb.conf systemLog: destination: file logAppend: true path: /mnt/data/mongod.log storage: dbPath: /mnt/data/ lockdep reports: [ 3437.452330] ====================================================== [ 3437.452750] WARNING: possible circular locking dependency detected [ 3437.453168] 6.7.0-rc7-custom+ #85 Tainted: G E [ 3437.453562] ------------------------------------------------------ [ 3437.453981] bcachefs/35533 is trying to acquire lock: [ 3437.454325] ffffa0a02b2b1418 (sb_writers#10){.+.+}-{0:0}, at: filename_create+0x62/0x190 [ 3437.454875] but task is already holding lock: [ 3437.455268] ffffa0a02b2b10e0 (&type->s_umount_key#48){.+.+}-{3:3}, at: bch2_fs_file_ioctl+0x232/0xc90 [bcachefs] [ 3437.456009] which lock already depends on the new lock. [ 3437.456553] the existing dependency chain (in reverse order) is: [ 3437.457054] -> #3 (&type->s_umount_key#48){.+.+}-{3:3}: [ 3437.457507] down_read+0x3e/0x170 [ 3437.457772] bch2_fs_file_ioctl+0x232/0xc90 [bcachefs] [ 3437.458206] __x64_sys_ioctl+0x93/0xd0 [ 3437.458498] do_syscall_64+0x42/0xf0 [ 3437.458779] entry_SYSCALL_64_after_hwframe+0x6e/0x76 [ 3437.459155] -> #2 (&c->snapshot_create_lock){++++}-{3:3}: [ 3437.459615] down_read+0x3e/0x170 [ 3437.459878] bch2_truncate+0x82/0x110 [bcachefs] [ 3437.460276] bchfs_truncate+0x254/0x3c0 [bcachefs] [ 3437.460686] notify_change+0x1f1/0x4a0 [ 3437.461283] do_truncate+0x7f/0xd0 [ 3437.461555] path_openat+0xa57/0xce0 [ 3437.461836] do_filp_open+0xb4/0x160 [ 3437.462116] do_sys_openat2+0x91/0xc0 [ 3437.462402] __x64_sys_openat+0x53/0xa0 [ 3437.462701] do_syscall_64+0x42/0xf0 [ 3437.462982] entry_SYSCALL_64_after_hwframe+0x6e/0x76 [ 3437.463359] -> #1 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}: [ 3437.463843] down_write+0x3b/0xc0 [ 3437.464223] bch2_write_iter+0x5b/0xcc0 [bcachefs] [ 3437.464493] vfs_write+0x21b/0x4c0 [ 3437.464653] ksys_write+0x69/0xf0 [ 3437.464839] do_syscall_64+0x42/0xf0 [ 3437.465009] entry_SYSCALL_64_after_hwframe+0x6e/0x76 [ 3437.465231] -> #0 (sb_writers#10){.+.+}-{0:0}: [ 3437.465471] __lock_acquire+0x1455/0x21b0 [ 3437.465656] lock_acquire+0xc6/0x2b0 [ 3437.465822] mnt_want_write+0x46/0x1a0 [ 3437.465996] filename_create+0x62/0x190 [ 3437.466175] user_path_create+0x2d/0x50 [ 3437.466352] bch2_fs_file_ioctl+0x2ec/0xc90 [bcachefs] [ 3437.466617] __x64_sys_ioctl+0x93/0xd0 [ 3437.466791] do_syscall_64+0x42/0xf0 [ 3437.466957] entry_SYSCALL_64_after_hwframe+0x6e/0x76 [ 3437.467180] other info that might help us debug this: [ 3437.469670] 2 locks held by bcachefs/35533: other info that might help us debug this: [ 3437.467507] Chain exists of: sb_writers#10 --> &c->snapshot_create_lock --> &type->s_umount_key#48 [ 3437.467979] Possible unsafe locking scenario: [ 3437.468223] CPU0 CPU1 [ 3437.468405] ---- ---- [ 3437.468585] rlock(&type->s_umount_key#48); [ 3437.468758] lock(&c->snapshot_create_lock); [ 3437.469030] lock(&type->s_umount_key#48); [ 3437.469291] rlock(sb_writers#10); [ 3437.469434] *** DEADLOCK *** [ 3437.469670] 2 locks held by bcachefs/35533: [ 3437.469838] #0: ffffa0a02ce00a88 (&c->snapshot_create_lock){++++}-{3:3}, at: bch2_fs_file_ioctl+0x1e3/0xc90 [bcachefs] [ 3437.470294] #1: ffffa0a02b2b10e0 (&type->s_umount_key#48){.+.+}-{3:3}, at: bch2_fs_file_ioctl+0x232/0xc90 [bcachefs] [ 3437.470744] stack backtrace: [ 3437.470922] CPU: 7 PID: 35533 Comm: bcachefs Kdump: loaded Tainted: G E 6.7.0-rc7-custom+ #85 [ 3437.471313] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014 [ 3437.471694] Call Trace: [ 3437.471795] <TASK> [ 3437.471884] dump_stack_lvl+0x57/0x90 [ 3437.472035] check_noncircular+0x132/0x150 [ 3437.472202] __lock_acquire+0x1455/0x21b0 [ 3437.472369] lock_acquire+0xc6/0x2b0 [ 3437.472518] ? filename_create+0x62/0x190 [ 3437.472683] ? lock_is_held_type+0x97/0x110 [ 3437.472856] mnt_want_write+0x46/0x1a0 [ 3437.473025] ? filename_create+0x62/0x190 [ 3437.473204] filename_create+0x62/0x190 [ 3437.473380] user_path_create+0x2d/0x50 [ 3437.473555] bch2_fs_file_ioctl+0x2ec/0xc90 [bcachefs] [ 3437.473819] ? lock_acquire+0xc6/0x2b0 [ 3437.474002] ? __fget_files+0x2a/0x190 [ 3437.474195] ? __fget_files+0xbc/0x190 [ 3437.474380] ? lock_release+0xc5/0x270 [ 3437.474567] ? __x64_sys_ioctl+0x93/0xd0 [ 3437.474764] ? __pfx_bch2_fs_file_ioctl+0x10/0x10 [bcachefs] [ 3437.475090] __x64_sys_ioctl+0x93/0xd0 [ 3437.475277] do_syscall_64+0x42/0xf0 [ 3437.475454] entry_SYSCALL_64_after_hwframe+0x6e/0x76 [ 3437.475691] RIP: 0033:0x7f2743c313af ====================================================== In __bch2_ioctl_subvolume_create(), we grab s_umount unconditionally and unlock it at the end of the function. There is a comment "why do we need this lock?" about the lock coming from commit 42d237320e98 ("bcachefs: Snapshot creation, deletion") The reason is that __bch2_ioctl_subvolume_create() calls sync_inodes_sb() which enforce locked s_umount to writeback all dirty nodes before doing snapshot works. Fix it by read locking s_umount for snapshotting only and unlocking s_umount after sync_inodes_sb(). Signed-off-by: Su Yue <glass.su@suse.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>