- 25 Jul, 2022 19 commits
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Qu Wenruo authored
Add tracepoint for better insight to how the RAID56 data are submitted. The output looks like this: (trace event header and UUID skipped) raid56_read_partial: full_stripe=389152768 devid=3 type=DATA1 offset=32768 opf=0x0 physical=323059712 len=32768 raid56_read_partial: full_stripe=389152768 devid=1 type=DATA2 offset=0 opf=0x0 physical=67174400 len=65536 raid56_write_stripe: full_stripe=389152768 devid=3 type=DATA1 offset=0 opf=0x1 physical=323026944 len=32768 raid56_write_stripe: full_stripe=389152768 devid=2 type=PQ1 offset=0 opf=0x1 physical=323026944 len=32768 The above debug output is from a 32K data write into an empty RAID56 data chunk. Some explanation on the event output: full_stripe: the logical bytenr of the full stripe devid: btrfs devid type: raid stripe type. DATA1: the first data stripe DATA2: the second data stripe PQ1: the P stripe PQ2: the Q stripe offset: the offset inside the stripe. opf: the bio op type physical: the physical offset the bio is for len: the length of the bio The first two lines are from partial RMW read, which is reading the remaining data stripes from disks. The last two lines are for full stripe RMW write, which is writing the involved two 16K stripes (one for DATA1 stripe, one for P stripe). The stripe for DATA2 doesn't need to be written. There are 5 types of trace events: - raid56_read_partial Read remaining data for regular read/write path. - raid56_write_stripe Write the modified stripes for regular read/write path. - raid56_scrub_read_recover Read remaining data for scrub recovery path. - raid56_scrub_write_stripe Write the modified stripes for scrub path. - raid56_scrub_read Read remaining data for scrub path. Also, since the trace events are included at super.c, we have to export needed structure definitions to 'raid56.h' and include the header in super.c, or we're unable to access those members. Signed-off-by:Qu Wenruo <wqu@suse.com> Reviewed-by:
David Sterba <dsterba@suse.com> [ reformat comments ] Signed-off-by:
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Qu Wenruo authored
[BUG] With added debugging, it turns out the following write sequence would cause extra read which is unnecessary: # xfs_io -f -s -c "pwrite -b 32k 0 32k" -c "pwrite -b 32k 32k 32k" \ -c "pwrite -b 32k 64k 32k" -c "pwrite -b 32k 96k 32k" \ $mnt/file The debug message looks like this (btrfs header skipped): partial rmw, full stripe=389152768 opf=0x0 devid=3 type=1 offset=32768 physical=323059712 len=32768 partial rmw, full stripe=389152768 opf=0x0 devid=1 type=2 offset=0 physical=67174400 len=65536 full stripe rmw, full stripe=389152768 opf=0x1 devid=3 type=1 offset=0 physical=323026944 len=32768 full stripe rmw, full stripe=389152768 opf=0x1 devid=2 type=-1 offset=0 physical=323026944 len=32768 partial rmw, full stripe=298844160 opf=0x0 devid=1 type=1 offset=32768 physical=22052864 len=32768 partial rmw, full stripe=298844160 opf=0x0 devid=2 type=2 offset=0 physical=277872640 len=65536 full stripe rmw, full stripe=298844160 opf=0x1 devid=1 type=1 offset=0 physical=22020096 len=32768 full stripe rmw, full stripe=298844160 opf=0x1 devid=3 type=-1 offset=0 physical=277872640 len=32768 partial rmw, full stripe=389152768 opf=0x0 devid=3 type=1 offset=0 physical=323026944 len=32768 partial rmw, full stripe=389152768 opf=0x0 devid=1 type=2 offset=0 physical=67174400 len=65536 ^^^^ Still partial read, even 389152768 is already cached by the first. write. full stripe rmw, full stripe=389152768 opf=0x1 devid=3 type=1 offset=32768 physical=323059712 len=32768 full stripe rmw, full stripe=389152768 opf=0x1 devid=2 type=-1 offset=32768 physical=323059712 len=32768 partial rmw, full stripe=298844160 opf=0x0 devid=1 type=1 offset=0 physical=22020096 len=32768 partial rmw, full stripe=298844160 opf=0x0 devid=2 type=2 offset=0 physical=277872640 len=65536 ^^^^ Still partial read for 298844160. full stripe rmw, full stripe=298844160 opf=0x1 devid=1 type=1 offset=32768 physical=22052864 len=32768 full stripe rmw, full stripe=298844160 opf=0x1 devid=3 type=-1 offset=32768 physical=277905408 len=32768 This means every 32K writes, even they are in the same full stripe, still trigger read for previously cached data. This would cause extra RAID56 IO, making the btrfs raid56 cache useless. [CAUSE] Commit d4e28d9b ("btrfs: raid56: make steal_rbio() subpage compatible") tries to make steal_rbio() subpage compatible, but during that conversion, there is one thing missing. We no longer rely on PageUptodate(rbio->stripe_pages[i]), but rbio->stripe_nsectors[i].uptodate to determine if a sector is uptodate. This means, previously if we switch the pointer, everything is done, as the PageUptodate flag is still bound to that page. But now we have to manually mark the involved sectors uptodate, or later raid56_rmw_stripe() will find the stolen sector is not uptodate, and assemble the read bio for it, wasting IO. [FIX] We can easily fix the bug, by also update the rbio->stripe_sectors[].uptodate in steal_rbio(). With this fixed, now the same write pattern no longer leads to the same unnecessary read: partial rmw, full stripe=389152768 opf=0x0 devid=3 type=1 offset=32768 physical=323059712 len=32768 partial rmw, full stripe=389152768 opf=0x0 devid=1 type=2 offset=0 physical=67174400 len=65536 full stripe rmw, full stripe=389152768 opf=0x1 devid=3 type=1 offset=0 physical=323026944 len=32768 full stripe rmw, full stripe=389152768 opf=0x1 devid=2 type=-1 offset=0 physical=323026944 len=32768 partial rmw, full stripe=298844160 opf=0x0 devid=1 type=1 offset=32768 physical=22052864 len=32768 partial rmw, full stripe=298844160 opf=0x0 devid=2 type=2 offset=0 physical=277872640 len=65536 full stripe rmw, full stripe=298844160 opf=0x1 devid=1 type=1 offset=0 physical=22020096 len=32768 full stripe rmw, full stripe=298844160 opf=0x1 devid=3 type=-1 offset=0 physical=277872640 len=32768 ^^^ No more partial read, directly into the write path. full stripe rmw, full stripe=389152768 opf=0x1 devid=3 type=1 offset=32768 physical=323059712 len=32768 full stripe rmw, full stripe=389152768 opf=0x1 devid=2 type=-1 offset=32768 physical=323059712 len=32768 full stripe rmw, full stripe=298844160 opf=0x1 devid=1 type=1 offset=32768 physical=22052864 len=32768 full stripe rmw, full stripe=298844160 opf=0x1 devid=3 type=-1 offset=32768 physical=277905408 len=32768 Fixes: d4e28d9b ("btrfs: raid56: make steal_rbio() subpage compatible") Signed-off-by:
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David Sterba authored
Both memzero_page and memcpy_to_page already call flush_dcache_page so we can remove the calls from btrfs code. Reviewed-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
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Qu Wenruo authored
If we have only 8K partial write at the beginning of a full RAID56 stripe, we will write the following contents: 0 8K 32K 64K Disk 1 (data): |XX| | | Disk 2 (data): | | | Disk 3 (parity): |XXXXXXXXXXXXXXX|XXXXXXXXXXXXXXX| |X| means the sector will be written back to disk. Note that, although we won't write any sectors from disk 2, but we will write the full 64KiB of parity to disk. This behavior is fine for now, but not for the future (especially for RAID56J, as we waste quite some space to journal the unused parity stripes). So here we will also utilize the btrfs_raid_bio::dbitmap, anytime we queue a higher level bio into an rbio, we will update rbio::dbitmap to indicate which vertical stripes we need to writeback. And at finish_rmw(), we also check dbitmap to see if we need to write any sector in the vertical stripe. So after the patch, above example will only lead to the following writeback pattern: 0 8K 32K 64K Disk 1 (data): |XX| | | Disk 2 (data): | | | Disk 3 (parity): |XX| | | Signed-off-by: -
Qu Wenruo authored
Previously we use "unsigned long *" for those two bitmaps. But since we only support fixed stripe length (64KiB, already checked in tree-checker), "unsigned long *" is really a waste of memory, while we can just use "unsigned long". This saves us 8 bytes in total for scrub_parity. To be extra safe, add an ASSERT() making sure calclulated @nsectors is always smaller than BITS_PER_LONG. Signed-off-by:
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Qu Wenruo authored
Previsouly we use "unsigned long *" for those two bitmaps. But since we only support fixed stripe length (64KiB, already checked in tree-checker), "unsigned long *" is really a waste of memory, while we can just use "unsigned long". This saves us 8 bytes in total for btrfs_raid_bio. To be extra safe, add an ASSERT() making sure calculated @stripe_nsectors is always smaller than BITS_PER_LONG. Signed-off-by:
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Nikolay Borisov authored
This eliminates 2 labels and makes the code generally more streamlined. Also rename the 'out_bargs' label to 'out_unlock' since bargs is going to be freed under the 'out' label. This also fixes a memory leak since bargs wasn't correctly freed in one of the condition which are now moved in btrfs_try_lock_balance. Signed-off-by:
Nikolay Borisov <nborisov@suse.com> Reviewed-by:
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Nikolay Borisov authored
This function contains the factored out locking sequence of btrfs_ioctl_balance. Having this piece of code separate helps to simplify btrfs_ioctl_balance which has too complicated. This will be used in the next patch to streamline the logic in btrfs_ioctl_balance. Signed-off-by:
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Christoph Hellwig authored
Use the new btrfs_bio_for_each_sector iterator to simplify btrfs_check_read_dio_bio. Reviewed-by:
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Qu Wenruo authored
Add a helper that works similar to __bio_for_each_segment, but instead of iterating over PAGE_SIZE chunks it iterates over each sector. Reviewed-by:
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Christoph Hellwig authored
Add a helper to find the csum for a byte offset into the csum buffer. Reviewed-by:
Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by:
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Christoph Hellwig authored
Untangle the goto and move the code it jumps to so it goes in the order of the most likely states first. Reviewed-by:
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Christoph Hellwig authored
Add a helper to end I/O on a single sector, which will come in handy with the new read repair code. Reviewed-by:
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Qu Wenruo authored
The function submit_data_read_repair() is only called for buffered data read path, thus those members can be calculated using bvec directly: - start start = page_offset(bvec->bv_page) + bvec->bv_offset; - end end = start + bvec->bv_len - 1; - page page = bvec->bv_page; - pgoff pgoff = bvec->bv_offset; Thus we can safely replace those 4 parameters with just one bio_vec. Also remove the unused return value. Reviewed-by:
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Qu Wenruo authored
Although we have several data csum verification code, we never have a function really just to verify checksum for one sector. Function check_data_csum() do extra work for error reporting, thus it requires a lot of extra things like file offset, bio_offset etc. Function btrfs_verify_data_csum() is even worse, it will utilize page checked flag, which means it can not be utilized for direct IO pages. Here we introduce a new helper, btrfs_check_sector_csum(), which really only accept a sector in page, and expected checksum pointer. We use this function to implement check_data_csum(), and export it for incoming patch. Reviewed-by:
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Qu Wenruo authored
The following functions do special handling for RAID56 chunks: - btrfs_is_parity_mirror() Check if the range is in RAID56 chunks. - btrfs_full_stripe_len() Either return sectorsize for non-RAID56 profiles or full stripe length for RAID56 chunks. But if a filesystem without any RAID56 chunks, it will not have RAID56 incompat flags, and we can skip the chunk tree looking up completely. Reviewed-by:
Anand Jain <anand.jain@oracle.com> Reviewed-by:
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Fanjun Kong authored
The <linux/mm.h> already provides the PAGE_ALIGNED macro. Let's use it instead of IS_ALIGNED and passing PAGE_SIZE directly. Reviewed-by:
Muchun Song <songmuchun@bytedance.com> Reviewed-by:
Fanjun Kong <bh1scw@gmail.com> Reviewed-by:
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Pankaj Raghav authored
Fix the comment to represent the actual logic used for sb_write_pointer - Empty[0] && In use[1] should be an invalid state instead of returning zone 0 wp - Empty[0] && Full[1] should be returning zone 0 wp instead of zone 1 wp - In use[0] && Empty[1] should be returning zone 0 wp instead of being an invalid state - In use[0] && Full[1] should be returning zone 0 wp instead of returning zone 1 wp - Full[0] && Empty[1] should be returning zone 1 wp instead of returning zone 0 wp - Full[0] && In use[1] should be returning zone 1 wp instead of returning zone 0 wp Reviewed-by:
Pankaj Raghav <p.raghav@samsung.com> Reviewed-by:
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David Sterba authored
Codespell has found a few typos. Signed-off-by:
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- 24 Jul, 2022 6 commits
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Linus Torvalds authored
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Adam Borowski authored
This code requires x509_load_certificate_list() to be built-in. Fixes: 60050ffe ("certs: Move load_certificate_list() to be with the asymmetric keys code") Reported-by:
kernel test robot <lkp@intel.com> Reported-by:
Steven Rostedt <rostedt@goodmis.org> Link: https://lore.kernel.org/all/202206221515.DqpUuvbQ-lkp@intel.com/ Link: https://lore.kernel.org/all/20220712104554.408dbf42@gandalf.local.home/Signed-off-by:
Adam Borowski <kilobyte@angband.pl> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull perf fix from Borislav Petkov: - Reorganize the perf LBR init code so that a TSX quirk is applied early enough in order for the LBR MSR access to not #GP * tag 'perf_urgent_for_v5.19_rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/x86/intel/lbr: Fix unchecked MSR access error on HSW
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull scheduler fix from Borislav Petkov: "A single fix to correct a wrong BUG_ON() condition for deboosted tasks" * tag 'sched_urgent_for_v5.19_rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/deadline: Fix BUG_ON condition for deboosted tasks
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull x86 fixes from Borislav Petkov: "A couple more retbleed fallout fixes. It looks like their urgency is decreasing so it seems like we've managed to catch whatever snafus the limited -rc testing has exposed. Maybe we're getting ready... :) - Make retbleed mitigations 64-bit only (32-bit will need a bit more work if even needed, at all). - Prevent return thunks patching of the LKDTM modules as it is not needed there - Avoid writing the SPEC_CTRL MSR on every kernel entry on eIBRS parts - Enhance error output of apply_returns() when it fails to patch a return thunk - A sparse fix to the sev-guest module - Protect EFI fw calls by issuing an IBPB on AMD" * tag 'x86_urgent_for_v5.19_rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/speculation: Make all RETbleed mitigations 64-bit only lkdtm: Disable return thunks in rodata.c x86/bugs: Warn when "ibrs" mitigation is selected on Enhanced IBRS parts x86/alternative: Report missing return thunk details virt: sev-guest: Pass the appropriate argument type to iounmap() x86/amd: Use IBPB for firmware calls -
git://git.kernel.org/pub/scm/linux/kernel/git/clk/linuxLinus Torvalds authored
Pull clk fix from Stephen Boyd: "One more fix to set the correct IO mapping for a clk gate in the lan966x driver" * tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux: clk: lan966x: Fix the lan966x clock gate register address
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- 23 Jul, 2022 2 commits
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git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds authored
Pull kvm fixes from Paolo Bonzini: - Check for invalid flags to KVM_CAP_X86_USER_SPACE_MSR - Fix use of sched_setaffinity in selftests - Sync kernel headers to tools - Fix KVM_STATS_UNIT_MAX * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: KVM: x86: Protect the unused bits in MSR exiting flags tools headers UAPI: Sync linux/kvm.h with the kernel sources KVM: selftests: Fix target thread to be migrated in rseq_test KVM: stats: Fix value for KVM_STATS_UNIT_MAX for boolean stats
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Ben Hutchings authored
The mitigations for RETBleed are currently ineffective on x86_32 since entry_32.S does not use the required macros. However, for an x86_32 target, the kconfig symbols for them are still enabled by default and /sys/devices/system/cpu/vulnerabilities/retbleed will wrongly report that mitigations are in place. Make all of these symbols depend on X86_64, and only enable RETHUNK by default on X86_64. Fixes: f43b9876 ("x86/retbleed: Add fine grained Kconfig knobs") Signed-off-by:
Ben Hutchings <ben@decadent.org.uk> Signed-off-by:
Borislav Petkov <bp@suse.de> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/YtwSR3NNsWp1ohfV@decadent.org.uk
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- 22 Jul, 2022 13 commits
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git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spiLinus Torvalds authored
Pull spi fixes from Mark Brown: "A few more small driver specific fixes" * tag 'spi-fix-v5.19-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi: spi: spi-rspi: Fix PIO fallback on RZ platforms spi: spi-cadence: Fix SPI NO Slave Select macro definition spi: bcm2835: bcm2835_spi_handle_err(): fix NULL pointer deref for non DMA transfers
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git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linuxLinus Torvalds authored
Pull RISC-V fixes from Palmer Dabbelt: - Two kexec-related build fixes - A DTS update to make the GPIO nodes match the upcoming dtschema - A fix that passes -mno-relax directly to the assembler when building modules, to work around compilers that fail to do so * tag 'riscv-for-linus-5.19-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: riscv: add as-options for modules with assembly compontents riscv: dts: align gpio-key node names with dtschema RISC-V: kexec: Fix build error without CONFIG_KEXEC RISCV: kexec: Fix build error without CONFIG_MODULES
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pmLinus Torvalds authored
Pull ACPI fix from Rafael Wysocki: "Fix yet another piece of ACPI CPPC changes fallout on AMD platforms (Mario Limonciello)" * tag 'acpi-5.19-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: ACPI: CPPC: Don't require flexible address space if X86_FEATURE_CPPC is supported
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git://git.kernel.dk/linux-blockLinus Torvalds authored
Pull io_uring fixes from Jens Axboe: "Fix for a bad kfree() introduced in this cycle, and a quick fix for disabling buffer recycling for IORING_OP_READV. The latter will get reworked for 5.20, but it gets the job done for 5.19" * tag 'io_uring-5.19-2022-07-21' of git://git.kernel.dk/linux-block: io_uring: do not recycle buffer in READV io_uring: fix free of unallocated buffer list
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git://git.kernel.dk/linux-blockLinus Torvalds authored
Pull block fix from Jens Axboe: "Just a single fix for missing error propagation for an allocation failure in raid5" * tag 'block-5.19-2022-07-21' of git://git.kernel.dk/linux-block: md/raid5: missing error code in setup_conf()
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git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linuxLinus Torvalds authored
Pull i2c fixes from Wolfram Sang: "Two driver bugfixes and a typo fix" * tag 'i2c-for-5.19-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: i2c: cadence: Change large transfer count reset logic to be unconditional i2c: imx: fix typo in comment i2c: mlxcpld: Fix register setting for 400KHz frequency
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git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linuxLinus Torvalds authored
Pull gpio fixes from Bartosz Golaszewski: - fix several regmap usage issues in gpio-pca953x - fix out-of-tree build for GPIO selftests - fix integer overflow in gpio-xilinx * tag 'gpio-fixes-for-v5.19-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux: gpio: gpio-xilinx: Fix integer overflow selftests: gpio: fix include path to kernel headers for out of tree builds gpio: pca953x: use the correct register address when regcache sync during init gpio: pca953x: use the correct range when do regmap sync gpio: pca953x: only use single read/write for No AI mode
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git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrlLinus Torvalds authored
Pull pin control fixes from Linus Walleij: "Only driver fixes: - NULL check for the ralink and sunplus drivers - Add Jacky Bai as maintainer for the Freescale pin controllers - Fix pin config ops for the Ocelot LAN966x and SparX5 - Disallow AMD pin control to be a module: the GPIO lines need to be active in early boot, so no can do - Fix the Armada 37xx to use raw spinlocks in the interrupt handler path to avoid wait context" * tag 'pinctrl-v5.19-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: pinctrl: armada-37xx: use raw spinlocks for regmap to avoid invalid wait context pinctrl: armada-37xx: make irq_lock a raw spinlock to avoid invalid wait context pinctrl: Don't allow PINCTRL_AMD to be a module pinctrl: ocelot: Fix pincfg pinctrl: ocelot: Fix pincfg for lan966x MAINTAINERS: Update freescale pin controllers maintainer pinctrl: sunplus: Add check for kcalloc pinctrl: ralink: Check for null return of devm_kcalloc -
git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/soundLinus Torvalds authored
Pull sound fixes from Takashi Iwai: "Only undoes the Rockchip BCLK changes to address a regression" * tag 'sound-5.19-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: ASoC: rockchip-i2s: Undo BCLK pinctrl changes ASoC: rockchip: i2s: Fix NULL pointer dereference when pinctrl is not found
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git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmcLinus Torvalds authored
Pull MMC fix from Ulf Hansson: - sdhci-omap: Fix a lockdep warning while probing * tag 'mmc-v5.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc: mmc: sdhci-omap: Fix a lockdep warning for PM runtime init
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git://anongit.freedesktop.org/drm/drmLinus Torvalds authored
Pull drm fixes from Dave Airlie: "Fixes for this week. The main one is the i915 firmware fix for the phoronix reported issue. I've written some firmware guidelines as a result, should land in -next soon. Otherwise a few amdgpu fixes, a scheduler fix, ttm fix and two other minor ones. scheduler: - scheduling while atomic fix ttm: - locking fix edp: - variable typo fix i915: - add back support for v69 firmware on ADL-P amdgpu: - Drop redundant buffer cleanup that can lead to a segfault - Add a bo_list mutex to avoid possible list corruption in CS - dmub notification fix imx: - fix error path" * tag 'drm-fixes-2022-07-22' of git://anongit.freedesktop.org/drm/drm: drm/amdgpu: Protect the amdgpu_bo_list list with a mutex v2 drm/imx/dcss: Add missing of_node_put() in fail path drm/i915/guc: support v69 in parallel to v70 drm/i915/guc: Support programming the EU priority in the GuC descriptor drm/panel-edp: Fix variable typo when saving hpd absent delay from DT drm/amdgpu: Remove one duplicated ef removal drm/ttm: fix locking in vmap/vunmap TTM GEM helpers drm/scheduler: Don't kill jobs in interrupt context drm/amd/display: Fix new dmub notification enabling in DM
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Linus Torvalds authored
Merge tag 'rcu-urgent.2022.07.21a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu Pull RCU fix from Paul McKenney: "This contains a pair of commits that fix 282d8998 ("srcu: Prevent expedited GPs and blocking readers from consuming CPU"), which was itself a fix to an SRCU expedited grace-period problem that could prevent kernel live patching (KLP) from completing. That SRCU fix for KLP introduced large (as in minutes) boot-time delays to embedded Linux kernels running on qemu/KVM. These delays were due to the emulation of certain MMIO operations controlling memory layout, which were emulated with one expedited grace period per access. Common configurations required thousands of boot-time MMIO accesses, and thus thousands of boot-time expedited SRCU grace periods. In these configurations, the occasional sleeps that allowed KLP to proceed caused excessive boot delays. These commits preserve enough sleeps to permit KLP to proceed, but few enough that the virtual embedded kernels still boot reasonably quickly. This represents a regression introduced in the v5.19 merge window, and the bug is causing significant inconvenience" * tag 'rcu-urgent.2022.07.21a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: srcu: Make expedited RCU grace periods block even less frequently srcu: Block less aggressively for expedited grace periods
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Linus Torvalds authored
Sudip reports that alpha doesn't build properly, with errors like include/asm-generic/tlb.h:401:1: error: redefinition of 'tlb_update_vma_flags' 401 | tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) | ^~~~~~~~~~~~~~~~~~~~ include/asm-generic/tlb.h:372:1: note: previous definition of 'tlb_update_vma_flags' with type 'void(struct mmu_gather *, struct vm_area_struct *)' 372 | tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) { } the cause being that We have this odd situation where some architectures were never converted to the newer TLB flushing interfaces that have a range for the flush. Instead people left them alone, and we have them select the MMU_GATHER_NO_RANGE config option to make the tlb header files account for this. Peter Zijlstra cleaned some of these nasty header file games up in commits 1e9fdf21 ("mmu_gather: Remove per arch tlb_{start,end}_vma()") 18ba064e ("mmu_gather: Let there be one tlb_{start,end}_vma() implementation") but tlb_update_vma_flags() was left alone, and then commit b67fbebd ("mmu_gather: Force tlb-flush VM_PFNMAP vmas") ended up removing only _one_ of the two stale duplicate dummy inline functions. This removes the other stale one. Somebody braver than me should try to remove MMU_GATHER_NO_RANGE entirely, but it requires fixing up the oddball architectures that use it: alpha, m68k, microblaze, nios2 and openrisc. The fixups should be fairly straightforward ("fix the build errors it exposes by adding the appropriate range arguments"), but the reason this wasn't done in the first place is that so few people end up working on those architectures. But it could be done one architecture at a time, hint, hint. Reported-by:Sudip Mukherjee (Codethink) <sudipm.mukherjee@gmail.com> Fixes: b67fbebd ("mmu_gather: Force tlb-flush VM_PFNMAP vmas") Link: https://lore.kernel.org/all/YtpXh0QHWwaEWVAY@debian/ Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Nick Piggin <npiggin@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by:
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