linux/io_uring/rw.c

1405 lines
36 KiB

io_uring/rw: ensure poll based multishot read retries appropriately io_read_mshot() always relies on poll triggering retries, and this works fine as long as we do a retry per size of the buffer being read. The buffer size is given by the size of the buffer(s) in the given buffer group ID. But if we're reading less than what is available, then we don't always get to read everything that is available. For example, if the buffers available are 32 bytes and we have 64 bytes to read, then we'll correctly read the first 32 bytes and then wait for another poll trigger before we attempt the next read. This next poll trigger may never happen, in which case we just sit forever and never make progress, or it may trigger at some point in the future, and now we're just delivering the available data much later than we should have. io_read_mshot() could do retries itself, but that is wasteful as we'll be going through all of __io_read() again, and most likely in vain. Rather than do that, bump our poll reference count and have io_poll_check_events() do one more loop and check with vfs_poll() if we have more data to read. If we do, io_read_mshot() will get invoked again directly and we'll read the next chunk. io_poll_multishot_retry() must only get called from inside io_poll_issue(), which is our multishot retry handler, as we know we already "own" the request at this point. Cc: stable@vger.kernel.org Link: https://github.com/axboe/liburing/issues/1041 Fixes: fc68fcda0491 ("io_uring/rw: add support for IORING_OP_READ_MULTISHOT") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-01-27 13:44:58 -07:00
io_uring/rw: defer fsnotify calls to task context We can't call these off the kiocb completion as that might be off soft/hard irq context. Defer the calls to when we process the task_work for this request. That avoids valid complaints like: stack backtrace: CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.0.0-rc6-syzkaller-00321-g105a36f3694e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_usage_bug kernel/locking/lockdep.c:3961 [inline] valid_state kernel/locking/lockdep.c:3973 [inline] mark_lock_irq kernel/locking/lockdep.c:4176 [inline] mark_lock.part.0.cold+0x18/0xd8 kernel/locking/lockdep.c:4632 mark_lock kernel/locking/lockdep.c:4596 [inline] mark_usage kernel/locking/lockdep.c:4527 [inline] __lock_acquire+0x11d9/0x56d0 kernel/locking/lockdep.c:5007 lock_acquire kernel/locking/lockdep.c:5666 [inline] lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631 __fs_reclaim_acquire mm/page_alloc.c:4674 [inline] fs_reclaim_acquire+0x115/0x160 mm/page_alloc.c:4688 might_alloc include/linux/sched/mm.h:271 [inline] slab_pre_alloc_hook mm/slab.h:700 [inline] slab_alloc mm/slab.c:3278 [inline] __kmem_cache_alloc_lru mm/slab.c:3471 [inline] kmem_cache_alloc+0x39/0x520 mm/slab.c:3491 fanotify_alloc_fid_event fs/notify/fanotify/fanotify.c:580 [inline] fanotify_alloc_event fs/notify/fanotify/fanotify.c:813 [inline] fanotify_handle_event+0x1130/0x3f40 fs/notify/fanotify/fanotify.c:948 send_to_group fs/notify/fsnotify.c:360 [inline] fsnotify+0xafb/0x1680 fs/notify/fsnotify.c:570 __fsnotify_parent+0x62f/0xa60 fs/notify/fsnotify.c:230 fsnotify_parent include/linux/fsnotify.h:77 [inline] fsnotify_file include/linux/fsnotify.h:99 [inline] fsnotify_access include/linux/fsnotify.h:309 [inline] __io_complete_rw_common+0x485/0x720 io_uring/rw.c:195 io_complete_rw+0x1a/0x1f0 io_uring/rw.c:228 iomap_dio_complete_work fs/iomap/direct-io.c:144 [inline] iomap_dio_bio_end_io+0x438/0x5e0 fs/iomap/direct-io.c:178 bio_endio+0x5f9/0x780 block/bio.c:1564 req_bio_endio block/blk-mq.c:695 [inline] blk_update_request+0x3fc/0x1300 block/blk-mq.c:825 scsi_end_request+0x7a/0x9a0 drivers/scsi/scsi_lib.c:541 scsi_io_completion+0x173/0x1f70 drivers/scsi/scsi_lib.c:971 scsi_complete+0x122/0x3b0 drivers/scsi/scsi_lib.c:1438 blk_complete_reqs+0xad/0xe0 block/blk-mq.c:1022 __do_softirq+0x1d3/0x9c6 kernel/softirq.c:571 invoke_softirq kernel/softirq.c:445 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:650 irq_exit_rcu+0x5/0x20 kernel/softirq.c:662 common_interrupt+0xa9/0xc0 arch/x86/kernel/irq.c:240 Fixes: f63cf5192fe3 ("io_uring: ensure that fsnotify is always called") Link: https://lore.kernel.org/all/20220929135627.ykivmdks2w5vzrwg@quack3/ Reported-by: syzbot+dfcc5f4da15868df7d4d@syzkaller.appspotmail.com Reported-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-09-29 10:57:05 -06:00
io_uring/rw: defer fsnotify calls to task context We can't call these off the kiocb completion as that might be off soft/hard irq context. Defer the calls to when we process the task_work for this request. That avoids valid complaints like: stack backtrace: CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.0.0-rc6-syzkaller-00321-g105a36f3694e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_usage_bug kernel/locking/lockdep.c:3961 [inline] valid_state kernel/locking/lockdep.c:3973 [inline] mark_lock_irq kernel/locking/lockdep.c:4176 [inline] mark_lock.part.0.cold+0x18/0xd8 kernel/locking/lockdep.c:4632 mark_lock kernel/locking/lockdep.c:4596 [inline] mark_usage kernel/locking/lockdep.c:4527 [inline] __lock_acquire+0x11d9/0x56d0 kernel/locking/lockdep.c:5007 lock_acquire kernel/locking/lockdep.c:5666 [inline] lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631 __fs_reclaim_acquire mm/page_alloc.c:4674 [inline] fs_reclaim_acquire+0x115/0x160 mm/page_alloc.c:4688 might_alloc include/linux/sched/mm.h:271 [inline] slab_pre_alloc_hook mm/slab.h:700 [inline] slab_alloc mm/slab.c:3278 [inline] __kmem_cache_alloc_lru mm/slab.c:3471 [inline] kmem_cache_alloc+0x39/0x520 mm/slab.c:3491 fanotify_alloc_fid_event fs/notify/fanotify/fanotify.c:580 [inline] fanotify_alloc_event fs/notify/fanotify/fanotify.c:813 [inline] fanotify_handle_event+0x1130/0x3f40 fs/notify/fanotify/fanotify.c:948 send_to_group fs/notify/fsnotify.c:360 [inline] fsnotify+0xafb/0x1680 fs/notify/fsnotify.c:570 __fsnotify_parent+0x62f/0xa60 fs/notify/fsnotify.c:230 fsnotify_parent include/linux/fsnotify.h:77 [inline] fsnotify_file include/linux/fsnotify.h:99 [inline] fsnotify_access include/linux/fsnotify.h:309 [inline] __io_complete_rw_common+0x485/0x720 io_uring/rw.c:195 io_complete_rw+0x1a/0x1f0 io_uring/rw.c:228 iomap_dio_complete_work fs/iomap/direct-io.c:144 [inline] iomap_dio_bio_end_io+0x438/0x5e0 fs/iomap/direct-io.c:178 bio_endio+0x5f9/0x780 block/bio.c:1564 req_bio_endio block/blk-mq.c:695 [inline] blk_update_request+0x3fc/0x1300 block/blk-mq.c:825 scsi_end_request+0x7a/0x9a0 drivers/scsi/scsi_lib.c:541 scsi_io_completion+0x173/0x1f70 drivers/scsi/scsi_lib.c:971 scsi_complete+0x122/0x3b0 drivers/scsi/scsi_lib.c:1438 blk_complete_reqs+0xad/0xe0 block/blk-mq.c:1022 __do_softirq+0x1d3/0x9c6 kernel/softirq.c:571 invoke_softirq kernel/softirq.c:445 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:650 irq_exit_rcu+0x5/0x20 kernel/softirq.c:662 common_interrupt+0xa9/0xc0 arch/x86/kernel/irq.c:240 Fixes: f63cf5192fe3 ("io_uring: ensure that fsnotify is always called") Link: https://lore.kernel.org/all/20220929135627.ykivmdks2w5vzrwg@quack3/ Reported-by: syzbot+dfcc5f4da15868df7d4d@syzkaller.appspotmail.com Reported-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-09-29 10:57:05 -06:00
io_uring/rw: defer fsnotify calls to task context We can't call these off the kiocb completion as that might be off soft/hard irq context. Defer the calls to when we process the task_work for this request. That avoids valid complaints like: stack backtrace: CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.0.0-rc6-syzkaller-00321-g105a36f3694e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_usage_bug kernel/locking/lockdep.c:3961 [inline] valid_state kernel/locking/lockdep.c:3973 [inline] mark_lock_irq kernel/locking/lockdep.c:4176 [inline] mark_lock.part.0.cold+0x18/0xd8 kernel/locking/lockdep.c:4632 mark_lock kernel/locking/lockdep.c:4596 [inline] mark_usage kernel/locking/lockdep.c:4527 [inline] __lock_acquire+0x11d9/0x56d0 kernel/locking/lockdep.c:5007 lock_acquire kernel/locking/lockdep.c:5666 [inline] lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631 __fs_reclaim_acquire mm/page_alloc.c:4674 [inline] fs_reclaim_acquire+0x115/0x160 mm/page_alloc.c:4688 might_alloc include/linux/sched/mm.h:271 [inline] slab_pre_alloc_hook mm/slab.h:700 [inline] slab_alloc mm/slab.c:3278 [inline] __kmem_cache_alloc_lru mm/slab.c:3471 [inline] kmem_cache_alloc+0x39/0x520 mm/slab.c:3491 fanotify_alloc_fid_event fs/notify/fanotify/fanotify.c:580 [inline] fanotify_alloc_event fs/notify/fanotify/fanotify.c:813 [inline] fanotify_handle_event+0x1130/0x3f40 fs/notify/fanotify/fanotify.c:948 send_to_group fs/notify/fsnotify.c:360 [inline] fsnotify+0xafb/0x1680 fs/notify/fsnotify.c:570 __fsnotify_parent+0x62f/0xa60 fs/notify/fsnotify.c:230 fsnotify_parent include/linux/fsnotify.h:77 [inline] fsnotify_file include/linux/fsnotify.h:99 [inline] fsnotify_access include/linux/fsnotify.h:309 [inline] __io_complete_rw_common+0x485/0x720 io_uring/rw.c:195 io_complete_rw+0x1a/0x1f0 io_uring/rw.c:228 iomap_dio_complete_work fs/iomap/direct-io.c:144 [inline] iomap_dio_bio_end_io+0x438/0x5e0 fs/iomap/direct-io.c:178 bio_endio+0x5f9/0x780 block/bio.c:1564 req_bio_endio block/blk-mq.c:695 [inline] blk_update_request+0x3fc/0x1300 block/blk-mq.c:825 scsi_end_request+0x7a/0x9a0 drivers/scsi/scsi_lib.c:541 scsi_io_completion+0x173/0x1f70 drivers/scsi/scsi_lib.c:971 scsi_complete+0x122/0x3b0 drivers/scsi/scsi_lib.c:1438 blk_complete_reqs+0xad/0xe0 block/blk-mq.c:1022 __do_softirq+0x1d3/0x9c6 kernel/softirq.c:571 invoke_softirq kernel/softirq.c:445 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:650 irq_exit_rcu+0x5/0x20 kernel/softirq.c:662 common_interrupt+0xa9/0xc0 arch/x86/kernel/irq.c:240 Fixes: f63cf5192fe3 ("io_uring: ensure that fsnotify is always called") Link: https://lore.kernel.org/all/20220929135627.ykivmdks2w5vzrwg@quack3/ Reported-by: syzbot+dfcc5f4da15868df7d4d@syzkaller.appspotmail.com Reported-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-09-29 10:57:05 -06:00
io_uring/kbuf: switch to storing struct io_buffer_list locally Currently the buffer list is stored in struct io_kiocb. The buffer list can be of two types: 1) Classic/legacy buffer list. These don't need to get referenced after a buffer pick, and hence storing them in struct io_kiocb is perfectly fine. 2) Ring provided buffer lists. These DO need to be referenced after the initial buffer pick, as they need to get consumed later on. This can be either just incrementing the head of the ring, or it can be consuming parts of a buffer if incremental buffer consumptions has been configured. For case 2, io_uring needs to be careful not to access the buffer list after the initial pick-and-execute context. The core does recycling of these, but it's easy to make a mistake, because it's stored in the io_kiocb which does persist across multiple execution contexts. Either because it's a multishot request, or simply because it needed some kind of async trigger (eg poll) for retry purposes. Add a struct io_buffer_list to struct io_br_sel, which is always on stack for the various users of it. This prevents the buffer list from leaking outside of that execution context, and additionally it enables kbuf to not even pass back the struct io_buffer_list if the given context isn't appropriately locked already. This doesn't fix any bugs, it's simply a defensive measure to prevent any issues with reuse of a buffer list. Link: https://lore.kernel.org/r/20250821020750.598432-12-axboe@kernel.dk Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-08-20 20:03:39 -06:00
fs: Initial atomic write support An atomic write is a write issued with torn-write protection, meaning that for a power failure or any other hardware failure, all or none of the data from the write will be stored, but never a mix of old and new data. Userspace may add flag RWF_ATOMIC to pwritev2() to indicate that the write is to be issued with torn-write prevention, according to special alignment and length rules. For any syscall interface utilizing struct iocb, add IOCB_ATOMIC for iocb->ki_flags field to indicate the same. A call to statx will give the relevant atomic write info for a file: - atomic_write_unit_min - atomic_write_unit_max - atomic_write_segments_max Both min and max values must be a power-of-2. Applications can avail of atomic write feature by ensuring that the total length of a write is a power-of-2 in size and also sized between atomic_write_unit_min and atomic_write_unit_max, inclusive. Applications must ensure that the write is at a naturally-aligned offset in the file wrt the total write length. The value in atomic_write_segments_max indicates the upper limit for IOV_ITER iovcnt. Add file mode flag FMODE_CAN_ATOMIC_WRITE, so files which do not have the flag set will have RWF_ATOMIC rejected and not just ignored. Add a type argument to kiocb_set_rw_flags() to allows reads which have RWF_ATOMIC set to be rejected. Helper function generic_atomic_write_valid() can be used by FSes to verify compliant writes. There we check for iov_iter type is for ubuf, which implies iovcnt==1 for pwritev2(), which is an initial restriction for atomic_write_segments_max. Initially the only user will be bdev file operations write handler. We will rely on the block BIO submission path to ensure write sizes are compliant for the bdev, so we don't need to check atomic writes sizes yet. Signed-off-by: Prasad Singamsetty <prasad.singamsetty@oracle.com> jpg: merge into single patch and much rewrite Acked-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: John Garry <john.g.garry@oracle.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Link: https://lore.kernel.org/r/20240620125359.2684798-4-john.g.garry@oracle.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-06-20 12:53:52 +00:00
iov_iter work, part 1 - isolated cleanups and optimizations. One of the goals is to reduce the overhead of using ->read_iter() and ->write_iter() instead of ->read()/->write(); new_sync_{read,write}() has a surprising amount of overhead, in particular inside iocb_flags(). That's why the beginning of the series is in this pile; it's not directly iov_iter-related, but it's a part of the same work... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQQqUNBr3gm4hGXdBJlZ7Krx/gZQ6wUCYurGOQAKCRBZ7Krx/gZQ 6ysyAP91lvBfMRepcxpd9kvtuzWkU8A3rfSziZZteEHANB9Q7QEAiPn2a2OjWkcZ uAyUWfCkHCNx+dSMkEvUgR5okQ0exAM= =9UCV -----END PGP SIGNATURE----- Merge tag 'pull-work.iov_iter-base' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs iov_iter updates from Al Viro: "Part 1 - isolated cleanups and optimizations. One of the goals is to reduce the overhead of using ->read_iter() and ->write_iter() instead of ->read()/->write(). new_sync_{read,write}() has a surprising amount of overhead, in particular inside iocb_flags(). That's the explanation for the beginning of the series is in this pile; it's not directly iov_iter-related, but it's a part of the same work..." * tag 'pull-work.iov_iter-base' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: first_iovec_segment(): just return address iov_iter: massage calling conventions for first_{iovec,bvec}_segment() iov_iter: first_{iovec,bvec}_segment() - simplify a bit iov_iter: lift dealing with maxpages out of first_{iovec,bvec}_segment() iov_iter_get_pages{,_alloc}(): cap the maxsize with MAX_RW_COUNT iov_iter_bvec_advance(): don't bother with bvec_iter copy_page_{to,from}_iter(): switch iovec variants to generic keep iocb_flags() result cached in struct file iocb: delay evaluation of IS_SYNC(...) until we want to check IOCB_DSYNC struct file: use anonymous union member for rcuhead and llist btrfs: use IOMAP_DIO_NOSYNC teach iomap_dio_rw() to suppress dsync No need of likely/unlikely on calls of check_copy_size()
2022-08-03 13:50:22 -07:00
fs: Initial atomic write support An atomic write is a write issued with torn-write protection, meaning that for a power failure or any other hardware failure, all or none of the data from the write will be stored, but never a mix of old and new data. Userspace may add flag RWF_ATOMIC to pwritev2() to indicate that the write is to be issued with torn-write prevention, according to special alignment and length rules. For any syscall interface utilizing struct iocb, add IOCB_ATOMIC for iocb->ki_flags field to indicate the same. A call to statx will give the relevant atomic write info for a file: - atomic_write_unit_min - atomic_write_unit_max - atomic_write_segments_max Both min and max values must be a power-of-2. Applications can avail of atomic write feature by ensuring that the total length of a write is a power-of-2 in size and also sized between atomic_write_unit_min and atomic_write_unit_max, inclusive. Applications must ensure that the write is at a naturally-aligned offset in the file wrt the total write length. The value in atomic_write_segments_max indicates the upper limit for IOV_ITER iovcnt. Add file mode flag FMODE_CAN_ATOMIC_WRITE, so files which do not have the flag set will have RWF_ATOMIC rejected and not just ignored. Add a type argument to kiocb_set_rw_flags() to allows reads which have RWF_ATOMIC set to be rejected. Helper function generic_atomic_write_valid() can be used by FSes to verify compliant writes. There we check for iov_iter type is for ubuf, which implies iovcnt==1 for pwritev2(), which is an initial restriction for atomic_write_segments_max. Initially the only user will be bdev file operations write handler. We will rely on the block BIO submission path to ensure write sizes are compliant for the bdev, so we don't need to check atomic writes sizes yet. Signed-off-by: Prasad Singamsetty <prasad.singamsetty@oracle.com> jpg: merge into single patch and much rewrite Acked-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: John Garry <john.g.garry@oracle.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Link: https://lore.kernel.org/r/20240620125359.2684798-4-john.g.garry@oracle.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-06-20 12:53:52 +00:00
fs: Initial atomic write support An atomic write is a write issued with torn-write protection, meaning that for a power failure or any other hardware failure, all or none of the data from the write will be stored, but never a mix of old and new data. Userspace may add flag RWF_ATOMIC to pwritev2() to indicate that the write is to be issued with torn-write prevention, according to special alignment and length rules. For any syscall interface utilizing struct iocb, add IOCB_ATOMIC for iocb->ki_flags field to indicate the same. A call to statx will give the relevant atomic write info for a file: - atomic_write_unit_min - atomic_write_unit_max - atomic_write_segments_max Both min and max values must be a power-of-2. Applications can avail of atomic write feature by ensuring that the total length of a write is a power-of-2 in size and also sized between atomic_write_unit_min and atomic_write_unit_max, inclusive. Applications must ensure that the write is at a naturally-aligned offset in the file wrt the total write length. The value in atomic_write_segments_max indicates the upper limit for IOV_ITER iovcnt. Add file mode flag FMODE_CAN_ATOMIC_WRITE, so files which do not have the flag set will have RWF_ATOMIC rejected and not just ignored. Add a type argument to kiocb_set_rw_flags() to allows reads which have RWF_ATOMIC set to be rejected. Helper function generic_atomic_write_valid() can be used by FSes to verify compliant writes. There we check for iov_iter type is for ubuf, which implies iovcnt==1 for pwritev2(), which is an initial restriction for atomic_write_segments_max. Initially the only user will be bdev file operations write handler. We will rely on the block BIO submission path to ensure write sizes are compliant for the bdev, so we don't need to check atomic writes sizes yet. Signed-off-by: Prasad Singamsetty <prasad.singamsetty@oracle.com> jpg: merge into single patch and much rewrite Acked-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: John Garry <john.g.garry@oracle.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Link: https://lore.kernel.org/r/20240620125359.2684798-4-john.g.garry@oracle.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-06-20 12:53:52 +00:00
io_uring/kbuf: switch to storing struct io_buffer_list locally Currently the buffer list is stored in struct io_kiocb. The buffer list can be of two types: 1) Classic/legacy buffer list. These don't need to get referenced after a buffer pick, and hence storing them in struct io_kiocb is perfectly fine. 2) Ring provided buffer lists. These DO need to be referenced after the initial buffer pick, as they need to get consumed later on. This can be either just incrementing the head of the ring, or it can be consuming parts of a buffer if incremental buffer consumptions has been configured. For case 2, io_uring needs to be careful not to access the buffer list after the initial pick-and-execute context. The core does recycling of these, but it's easy to make a mistake, because it's stored in the io_kiocb which does persist across multiple execution contexts. Either because it's a multishot request, or simply because it needed some kind of async trigger (eg poll) for retry purposes. Add a struct io_buffer_list to struct io_br_sel, which is always on stack for the various users of it. This prevents the buffer list from leaking outside of that execution context, and additionally it enables kbuf to not even pass back the struct io_buffer_list if the given context isn't appropriately locked already. This doesn't fix any bugs, it's simply a defensive measure to prevent any issues with reuse of a buffer list. Link: https://lore.kernel.org/r/20250821020750.598432-12-axboe@kernel.dk Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-08-20 20:03:39 -06:00
io_uring/kbuf: switch to storing struct io_buffer_list locally Currently the buffer list is stored in struct io_kiocb. The buffer list can be of two types: 1) Classic/legacy buffer list. These don't need to get referenced after a buffer pick, and hence storing them in struct io_kiocb is perfectly fine. 2) Ring provided buffer lists. These DO need to be referenced after the initial buffer pick, as they need to get consumed later on. This can be either just incrementing the head of the ring, or it can be consuming parts of a buffer if incremental buffer consumptions has been configured. For case 2, io_uring needs to be careful not to access the buffer list after the initial pick-and-execute context. The core does recycling of these, but it's easy to make a mistake, because it's stored in the io_kiocb which does persist across multiple execution contexts. Either because it's a multishot request, or simply because it needed some kind of async trigger (eg poll) for retry purposes. Add a struct io_buffer_list to struct io_br_sel, which is always on stack for the various users of it. This prevents the buffer list from leaking outside of that execution context, and additionally it enables kbuf to not even pass back the struct io_buffer_list if the given context isn't appropriately locked already. This doesn't fix any bugs, it's simply a defensive measure to prevent any issues with reuse of a buffer list. Link: https://lore.kernel.org/r/20250821020750.598432-12-axboe@kernel.dk Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-08-20 20:03:39 -06:00
io_uring/kbuf: switch to storing struct io_buffer_list locally Currently the buffer list is stored in struct io_kiocb. The buffer list can be of two types: 1) Classic/legacy buffer list. These don't need to get referenced after a buffer pick, and hence storing them in struct io_kiocb is perfectly fine. 2) Ring provided buffer lists. These DO need to be referenced after the initial buffer pick, as they need to get consumed later on. This can be either just incrementing the head of the ring, or it can be consuming parts of a buffer if incremental buffer consumptions has been configured. For case 2, io_uring needs to be careful not to access the buffer list after the initial pick-and-execute context. The core does recycling of these, but it's easy to make a mistake, because it's stored in the io_kiocb which does persist across multiple execution contexts. Either because it's a multishot request, or simply because it needed some kind of async trigger (eg poll) for retry purposes. Add a struct io_buffer_list to struct io_br_sel, which is always on stack for the various users of it. This prevents the buffer list from leaking outside of that execution context, and additionally it enables kbuf to not even pass back the struct io_buffer_list if the given context isn't appropriately locked already. This doesn't fix any bugs, it's simply a defensive measure to prevent any issues with reuse of a buffer list. Link: https://lore.kernel.org/r/20250821020750.598432-12-axboe@kernel.dk Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-08-20 20:03:39 -06:00
io_uring/kbuf: switch to storing struct io_buffer_list locally Currently the buffer list is stored in struct io_kiocb. The buffer list can be of two types: 1) Classic/legacy buffer list. These don't need to get referenced after a buffer pick, and hence storing them in struct io_kiocb is perfectly fine. 2) Ring provided buffer lists. These DO need to be referenced after the initial buffer pick, as they need to get consumed later on. This can be either just incrementing the head of the ring, or it can be consuming parts of a buffer if incremental buffer consumptions has been configured. For case 2, io_uring needs to be careful not to access the buffer list after the initial pick-and-execute context. The core does recycling of these, but it's easy to make a mistake, because it's stored in the io_kiocb which does persist across multiple execution contexts. Either because it's a multishot request, or simply because it needed some kind of async trigger (eg poll) for retry purposes. Add a struct io_buffer_list to struct io_br_sel, which is always on stack for the various users of it. This prevents the buffer list from leaking outside of that execution context, and additionally it enables kbuf to not even pass back the struct io_buffer_list if the given context isn't appropriately locked already. This doesn't fix any bugs, it's simply a defensive measure to prevent any issues with reuse of a buffer list. Link: https://lore.kernel.org/r/20250821020750.598432-12-axboe@kernel.dk Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-08-20 20:03:39 -06:00
io_uring/kbuf: switch to storing struct io_buffer_list locally Currently the buffer list is stored in struct io_kiocb. The buffer list can be of two types: 1) Classic/legacy buffer list. These don't need to get referenced after a buffer pick, and hence storing them in struct io_kiocb is perfectly fine. 2) Ring provided buffer lists. These DO need to be referenced after the initial buffer pick, as they need to get consumed later on. This can be either just incrementing the head of the ring, or it can be consuming parts of a buffer if incremental buffer consumptions has been configured. For case 2, io_uring needs to be careful not to access the buffer list after the initial pick-and-execute context. The core does recycling of these, but it's easy to make a mistake, because it's stored in the io_kiocb which does persist across multiple execution contexts. Either because it's a multishot request, or simply because it needed some kind of async trigger (eg poll) for retry purposes. Add a struct io_buffer_list to struct io_br_sel, which is always on stack for the various users of it. This prevents the buffer list from leaking outside of that execution context, and additionally it enables kbuf to not even pass back the struct io_buffer_list if the given context isn't appropriately locked already. This doesn't fix any bugs, it's simply a defensive measure to prevent any issues with reuse of a buffer list. Link: https://lore.kernel.org/r/20250821020750.598432-12-axboe@kernel.dk Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-08-20 20:03:39 -06:00
io_uring/kbuf: switch to storing struct io_buffer_list locally Currently the buffer list is stored in struct io_kiocb. The buffer list can be of two types: 1) Classic/legacy buffer list. These don't need to get referenced after a buffer pick, and hence storing them in struct io_kiocb is perfectly fine. 2) Ring provided buffer lists. These DO need to be referenced after the initial buffer pick, as they need to get consumed later on. This can be either just incrementing the head of the ring, or it can be consuming parts of a buffer if incremental buffer consumptions has been configured. For case 2, io_uring needs to be careful not to access the buffer list after the initial pick-and-execute context. The core does recycling of these, but it's easy to make a mistake, because it's stored in the io_kiocb which does persist across multiple execution contexts. Either because it's a multishot request, or simply because it needed some kind of async trigger (eg poll) for retry purposes. Add a struct io_buffer_list to struct io_br_sel, which is always on stack for the various users of it. This prevents the buffer list from leaking outside of that execution context, and additionally it enables kbuf to not even pass back the struct io_buffer_list if the given context isn't appropriately locked already. This doesn't fix any bugs, it's simply a defensive measure to prevent any issues with reuse of a buffer list. Link: https://lore.kernel.org/r/20250821020750.598432-12-axboe@kernel.dk Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-08-20 20:03:39 -06:00
io_uring/rw: ensure poll based multishot read retries appropriately io_read_mshot() always relies on poll triggering retries, and this works fine as long as we do a retry per size of the buffer being read. The buffer size is given by the size of the buffer(s) in the given buffer group ID. But if we're reading less than what is available, then we don't always get to read everything that is available. For example, if the buffers available are 32 bytes and we have 64 bytes to read, then we'll correctly read the first 32 bytes and then wait for another poll trigger before we attempt the next read. This next poll trigger may never happen, in which case we just sit forever and never make progress, or it may trigger at some point in the future, and now we're just delivering the available data much later than we should have. io_read_mshot() could do retries itself, but that is wasteful as we'll be going through all of __io_read() again, and most likely in vain. Rather than do that, bump our poll reference count and have io_poll_check_events() do one more loop and check with vfs_poll() if we have more data to read. If we do, io_read_mshot() will get invoked again directly and we'll read the next chunk. io_poll_multishot_retry() must only get called from inside io_poll_issue(), which is our multishot retry handler, as we know we already "own" the request at this point. Cc: stable@vger.kernel.org Link: https://github.com/axboe/liburing/issues/1041 Fixes: fc68fcda0491 ("io_uring/rw: add support for IORING_OP_READ_MULTISHOT") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-01-27 13:44:58 -07:00
io_uring/rw: fix missing NOWAIT check for O_DIRECT start write When io_uring starts a write, it'll call kiocb_start_write() to bump the super block rwsem, preventing any freezes from happening while that write is in-flight. The freeze side will grab that rwsem for writing, excluding any new writers from happening and waiting for existing writes to finish. But io_uring unconditionally uses kiocb_start_write(), which will block if someone is currently attempting to freeze the mount point. This causes a deadlock where freeze is waiting for previous writes to complete, but the previous writes cannot complete, as the task that is supposed to complete them is blocked waiting on starting a new write. This results in the following stuck trace showing that dependency with the write blocked starting a new write: task:fio state:D stack:0 pid:886 tgid:886 ppid:876 Call trace: __switch_to+0x1d8/0x348 __schedule+0x8e8/0x2248 schedule+0x110/0x3f0 percpu_rwsem_wait+0x1e8/0x3f8 __percpu_down_read+0xe8/0x500 io_write+0xbb8/0xff8 io_issue_sqe+0x10c/0x1020 io_submit_sqes+0x614/0x2110 __arm64_sys_io_uring_enter+0x524/0x1038 invoke_syscall+0x74/0x268 el0_svc_common.constprop.0+0x160/0x238 do_el0_svc+0x44/0x60 el0_svc+0x44/0xb0 el0t_64_sync_handler+0x118/0x128 el0t_64_sync+0x168/0x170 INFO: task fsfreeze:7364 blocked for more than 15 seconds. Not tainted 6.12.0-rc5-00063-g76aaf945701c #7963 with the attempting freezer stuck trying to grab the rwsem: task:fsfreeze state:D stack:0 pid:7364 tgid:7364 ppid:995 Call trace: __switch_to+0x1d8/0x348 __schedule+0x8e8/0x2248 schedule+0x110/0x3f0 percpu_down_write+0x2b0/0x680 freeze_super+0x248/0x8a8 do_vfs_ioctl+0x149c/0x1b18 __arm64_sys_ioctl+0xd0/0x1a0 invoke_syscall+0x74/0x268 el0_svc_common.constprop.0+0x160/0x238 do_el0_svc+0x44/0x60 el0_svc+0x44/0xb0 el0t_64_sync_handler+0x118/0x128 el0t_64_sync+0x168/0x170 Fix this by having the io_uring side honor IOCB_NOWAIT, and only attempt a blocking grab of the super block rwsem if it isn't set. For normal issue where IOCB_NOWAIT would always be set, this returns -EAGAIN which will have io_uring core issue a blocking attempt of the write. That will in turn also get completions run, ensuring forward progress. Since freezing requires CAP_SYS_ADMIN in the first place, this isn't something that can be triggered by a regular user. Cc: stable@vger.kernel.org # 5.10+ Reported-by: Peter Mann <peter.mann@sh.cz> Link: https://lore.kernel.org/io-uring/38c94aec-81c9-4f62-b44e-1d87f5597644@sh.cz Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-10-31 08:05:44 -06:00
fs: Initial atomic write support An atomic write is a write issued with torn-write protection, meaning that for a power failure or any other hardware failure, all or none of the data from the write will be stored, but never a mix of old and new data. Userspace may add flag RWF_ATOMIC to pwritev2() to indicate that the write is to be issued with torn-write prevention, according to special alignment and length rules. For any syscall interface utilizing struct iocb, add IOCB_ATOMIC for iocb->ki_flags field to indicate the same. A call to statx will give the relevant atomic write info for a file: - atomic_write_unit_min - atomic_write_unit_max - atomic_write_segments_max Both min and max values must be a power-of-2. Applications can avail of atomic write feature by ensuring that the total length of a write is a power-of-2 in size and also sized between atomic_write_unit_min and atomic_write_unit_max, inclusive. Applications must ensure that the write is at a naturally-aligned offset in the file wrt the total write length. The value in atomic_write_segments_max indicates the upper limit for IOV_ITER iovcnt. Add file mode flag FMODE_CAN_ATOMIC_WRITE, so files which do not have the flag set will have RWF_ATOMIC rejected and not just ignored. Add a type argument to kiocb_set_rw_flags() to allows reads which have RWF_ATOMIC set to be rejected. Helper function generic_atomic_write_valid() can be used by FSes to verify compliant writes. There we check for iov_iter type is for ubuf, which implies iovcnt==1 for pwritev2(), which is an initial restriction for atomic_write_segments_max. Initially the only user will be bdev file operations write handler. We will rely on the block BIO submission path to ensure write sizes are compliant for the bdev, so we don't need to check atomic writes sizes yet. Signed-off-by: Prasad Singamsetty <prasad.singamsetty@oracle.com> jpg: merge into single patch and much rewrite Acked-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: John Garry <john.g.garry@oracle.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Link: https://lore.kernel.org/r/20240620125359.2684798-4-john.g.garry@oracle.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-06-20 12:53:52 +00:00
io_uring/rw: fix missing NOWAIT check for O_DIRECT start write When io_uring starts a write, it'll call kiocb_start_write() to bump the super block rwsem, preventing any freezes from happening while that write is in-flight. The freeze side will grab that rwsem for writing, excluding any new writers from happening and waiting for existing writes to finish. But io_uring unconditionally uses kiocb_start_write(), which will block if someone is currently attempting to freeze the mount point. This causes a deadlock where freeze is waiting for previous writes to complete, but the previous writes cannot complete, as the task that is supposed to complete them is blocked waiting on starting a new write. This results in the following stuck trace showing that dependency with the write blocked starting a new write: task:fio state:D stack:0 pid:886 tgid:886 ppid:876 Call trace: __switch_to+0x1d8/0x348 __schedule+0x8e8/0x2248 schedule+0x110/0x3f0 percpu_rwsem_wait+0x1e8/0x3f8 __percpu_down_read+0xe8/0x500 io_write+0xbb8/0xff8 io_issue_sqe+0x10c/0x1020 io_submit_sqes+0x614/0x2110 __arm64_sys_io_uring_enter+0x524/0x1038 invoke_syscall+0x74/0x268 el0_svc_common.constprop.0+0x160/0x238 do_el0_svc+0x44/0x60 el0_svc+0x44/0xb0 el0t_64_sync_handler+0x118/0x128 el0t_64_sync+0x168/0x170 INFO: task fsfreeze:7364 blocked for more than 15 seconds. Not tainted 6.12.0-rc5-00063-g76aaf945701c #7963 with the attempting freezer stuck trying to grab the rwsem: task:fsfreeze state:D stack:0 pid:7364 tgid:7364 ppid:995 Call trace: __switch_to+0x1d8/0x348 __schedule+0x8e8/0x2248 schedule+0x110/0x3f0 percpu_down_write+0x2b0/0x680 freeze_super+0x248/0x8a8 do_vfs_ioctl+0x149c/0x1b18 __arm64_sys_ioctl+0xd0/0x1a0 invoke_syscall+0x74/0x268 el0_svc_common.constprop.0+0x160/0x238 do_el0_svc+0x44/0x60 el0_svc+0x44/0xb0 el0t_64_sync_handler+0x118/0x128 el0t_64_sync+0x168/0x170 Fix this by having the io_uring side honor IOCB_NOWAIT, and only attempt a blocking grab of the super block rwsem if it isn't set. For normal issue where IOCB_NOWAIT would always be set, this returns -EAGAIN which will have io_uring core issue a blocking attempt of the write. That will in turn also get completions run, ensuring forward progress. Since freezing requires CAP_SYS_ADMIN in the first place, this isn't something that can be triggered by a regular user. Cc: stable@vger.kernel.org # 5.10+ Reported-by: Peter Mann <peter.mann@sh.cz> Link: https://lore.kernel.org/io-uring/38c94aec-81c9-4f62-b44e-1d87f5597644@sh.cz Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-10-31 08:05:44 -06:00
io_uring/kbuf: switch to storing struct io_buffer_list locally Currently the buffer list is stored in struct io_kiocb. The buffer list can be of two types: 1) Classic/legacy buffer list. These don't need to get referenced after a buffer pick, and hence storing them in struct io_kiocb is perfectly fine. 2) Ring provided buffer lists. These DO need to be referenced after the initial buffer pick, as they need to get consumed later on. This can be either just incrementing the head of the ring, or it can be consuming parts of a buffer if incremental buffer consumptions has been configured. For case 2, io_uring needs to be careful not to access the buffer list after the initial pick-and-execute context. The core does recycling of these, but it's easy to make a mistake, because it's stored in the io_kiocb which does persist across multiple execution contexts. Either because it's a multishot request, or simply because it needed some kind of async trigger (eg poll) for retry purposes. Add a struct io_buffer_list to struct io_br_sel, which is always on stack for the various users of it. This prevents the buffer list from leaking outside of that execution context, and additionally it enables kbuf to not even pass back the struct io_buffer_list if the given context isn't appropriately locked already. This doesn't fix any bugs, it's simply a defensive measure to prevent any issues with reuse of a buffer list. Link: https://lore.kernel.org/r/20250821020750.598432-12-axboe@kernel.dk Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-08-20 20:03:39 -06:00
A rather large update for timekeeping and timers: - The final step to get rid of auto-rearming posix-timers posix-timers are currently auto-rearmed by the kernel when the signal of the timer is ignored so that the timer signal can be delivered once the corresponding signal is unignored. This requires to throttle the timer to prevent a DoS by small intervals and keeps the system pointlessly out of low power states for no value. This is a long standing non-trivial problem due to the lock order of posix-timer lock and the sighand lock along with life time issues as the timer and the sigqueue have different life time rules. Cure this by: * Embedding the sigqueue into the timer struct to have the same life time rules. Aside of that this also avoids the lookup of the timer in the signal delivery and rearm path as it's just a always valid container_of() now. * Queuing ignored timer signals onto a seperate ignored list. * Moving queued timer signals onto the ignored list when the signal is switched to SIG_IGN before it could be delivered. * Walking the ignored list when SIG_IGN is lifted and requeue the signals to the actual signal lists. This allows the signal delivery code to rearm the timer. This also required to consolidate the signal delivery rules so they are consistent across all situations. With that all self test scenarios finally succeed. - Core infrastructure for VFS multigrain timestamping This is required to allow the kernel to use coarse grained time stamps by default and switch to fine grained time stamps when inode attributes are actively observed via getattr(). These changes have been provided to the VFS tree as well, so that the VFS specific infrastructure could be built on top. - Cleanup and consolidation of the sleep() infrastructure * Move all sleep and timeout functions into one file * Rework udelay() and ndelay() into proper documented inline functions and replace the hardcoded magic numbers by proper defines. * Rework the fsleep() implementation to take the reality of the timer wheel granularity on different HZ values into account. Right now the boundaries are hard coded time ranges which fail to provide the requested accuracy on different HZ settings. * Update documentation for all sleep/timeout related functions and fix up stale documentation links all over the place * Fixup a few usage sites - Rework of timekeeping and adjtimex(2) to prepare for multiple PTP clocks A system can have multiple PTP clocks which are participating in seperate and independent PTP clock domains. So far the kernel only considers the PTP clock which is based on CLOCK TAI relevant as that's the clock which drives the timekeeping adjustments via the various user space daemons through adjtimex(2). The non TAI based clock domains are accessible via the file descriptor based posix clocks, but their usability is very limited. They can't be accessed fast as they always go all the way out to the hardware and they cannot be utilized in the kernel itself. As Time Sensitive Networking (TSN) gains traction it is required to provide fast user and kernel space access to these clocks. The approach taken is to utilize the timekeeping and adjtimex(2) infrastructure to provide this access in a similar way how the kernel provides access to clock MONOTONIC, REALTIME etc. Instead of creating a duplicated infrastructure this rework converts timekeeping and adjtimex(2) into generic functionality which operates on pointers to data structures instead of using static variables. This allows to provide time accessors and adjtimex(2) functionality for the independent PTP clocks in a subsequent step. - Consolidate hrtimer initialization hrtimers are set up by initializing the data structure and then seperately setting the callback function for historical reasons. That's an extra unnecessary step and makes Rust support less straight forward than it should be. Provide a new set of hrtimer_setup*() functions and convert the core code and a few usage sites of the less frequently used interfaces over. The bulk of the htimer_init() to hrtimer_setup() conversion is already prepared and scheduled for the next merge window. - Drivers: * Ensure that the global timekeeping clocksource is utilizing the cluster 0 timer on MIPS multi-cluster systems. Otherwise CPUs on different clusters use their cluster specific clocksource which is not guaranteed to be synchronized with other clusters. * Mostly boring cleanups, fixes, improvements and code movement -----BEGIN PGP SIGNATURE----- iQJHBAABCgAxFiEEQp8+kY+LLUocC4bMphj1TA10mKEFAmc7kPITHHRnbHhAbGlu dXRyb25peC5kZQAKCRCmGPVMDXSYoZKkD/9OUL6fOJrDUmOYBa4QVeMyfTef4EaL tvwIMM/29XQFeiq3xxCIn+EMnHjXn2lvIhYGQ7GKsbKYwvJ7ZBDpQb+UMhZ2nKI9 6D6BP6WomZohKeH2fZbJQAdqOi3KRYdvQdIsVZUexkqiaVPphRvOH9wOr45gHtZM EyMRSotPlQTDqcrbUejDMEO94GyjDCYXRsyATLxjmTzL/N4xD4NRIiotjM2vL/a9 8MuCgIhrKUEyYlFoOxxeokBsF3kk3/ez2jlG9b/N8VLH3SYIc2zgL58FBgWxlmgG bY71nVG3nUgEjxBd2dcXAVVqvb+5widk8p6O7xxOAQKTLMcJ4H0tQDkMnzBtUzvB DGAJDHAmAr0g+ja9O35Pkhunkh4HYFIbq0Il4d1HMKObhJV0JumcKuQVxrXycdm3 UZfq3seqHsZJQbPgCAhlFU0/2WWScocbee9bNebGT33KVwSp5FoVv89C/6Vjb+vV Gusc3thqrQuMAZW5zV8g4UcBAA/xH4PB0I+vHib+9XPZ4UQ7/6xKl2jE0kd5hX7n AAUeZvFNFqIsY+B6vz+Jx/yzyM7u5cuXq87pof5EHVFzv56lyTp4ToGcOGYRgKH5 JXeYV1OxGziSDrd5vbf9CzdWMzqMvTefXrHbWrjkjhNOe8E1A8O88RZ5uRKZhmSw hZZ4hdM9+3T7cg== =2VC6 -----END PGP SIGNATURE----- Merge tag 'timers-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer updates from Thomas Gleixner: "A rather large update for timekeeping and timers: - The final step to get rid of auto-rearming posix-timers posix-timers are currently auto-rearmed by the kernel when the signal of the timer is ignored so that the timer signal can be delivered once the corresponding signal is unignored. This requires to throttle the timer to prevent a DoS by small intervals and keeps the system pointlessly out of low power states for no value. This is a long standing non-trivial problem due to the lock order of posix-timer lock and the sighand lock along with life time issues as the timer and the sigqueue have different life time rules. Cure this by: - Embedding the sigqueue into the timer struct to have the same life time rules. Aside of that this also avoids the lookup of the timer in the signal delivery and rearm path as it's just a always valid container_of() now. - Queuing ignored timer signals onto a seperate ignored list. - Moving queued timer signals onto the ignored list when the signal is switched to SIG_IGN before it could be delivered. - Walking the ignored list when SIG_IGN is lifted and requeue the signals to the actual signal lists. This allows the signal delivery code to rearm the timer. This also required to consolidate the signal delivery rules so they are consistent across all situations. With that all self test scenarios finally succeed. - Core infrastructure for VFS multigrain timestamping This is required to allow the kernel to use coarse grained time stamps by default and switch to fine grained time stamps when inode attributes are actively observed via getattr(). These changes have been provided to the VFS tree as well, so that the VFS specific infrastructure could be built on top. - Cleanup and consolidation of the sleep() infrastructure - Move all sleep and timeout functions into one file - Rework udelay() and ndelay() into proper documented inline functions and replace the hardcoded magic numbers by proper defines. - Rework the fsleep() implementation to take the reality of the timer wheel granularity on different HZ values into account. Right now the boundaries are hard coded time ranges which fail to provide the requested accuracy on different HZ settings. - Update documentation for all sleep/timeout related functions and fix up stale documentation links all over the place - Fixup a few usage sites - Rework of timekeeping and adjtimex(2) to prepare for multiple PTP clocks A system can have multiple PTP clocks which are participating in seperate and independent PTP clock domains. So far the kernel only considers the PTP clock which is based on CLOCK TAI relevant as that's the clock which drives the timekeeping adjustments via the various user space daemons through adjtimex(2). The non TAI based clock domains are accessible via the file descriptor based posix clocks, but their usability is very limited. They can't be accessed fast as they always go all the way out to the hardware and they cannot be utilized in the kernel itself. As Time Sensitive Networking (TSN) gains traction it is required to provide fast user and kernel space access to these clocks. The approach taken is to utilize the timekeeping and adjtimex(2) infrastructure to provide this access in a similar way how the kernel provides access to clock MONOTONIC, REALTIME etc. Instead of creating a duplicated infrastructure this rework converts timekeeping and adjtimex(2) into generic functionality which operates on pointers to data structures instead of using static variables. This allows to provide time accessors and adjtimex(2) functionality for the independent PTP clocks in a subsequent step. - Consolidate hrtimer initialization hrtimers are set up by initializing the data structure and then seperately setting the callback function for historical reasons. That's an extra unnecessary step and makes Rust support less straight forward than it should be. Provide a new set of hrtimer_setup*() functions and convert the core code and a few usage sites of the less frequently used interfaces over. The bulk of the htimer_init() to hrtimer_setup() conversion is already prepared and scheduled for the next merge window. - Drivers: - Ensure that the global timekeeping clocksource is utilizing the cluster 0 timer on MIPS multi-cluster systems. Otherwise CPUs on different clusters use their cluster specific clocksource which is not guaranteed to be synchronized with other clusters. - Mostly boring cleanups, fixes, improvements and code movement" * tag 'timers-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (140 commits) posix-timers: Fix spurious warning on double enqueue versus do_exit() clocksource/drivers/arm_arch_timer: Use of_property_present() for non-boolean properties clocksource/drivers/gpx: Remove redundant casts clocksource/drivers/timer-ti-dm: Fix child node refcount handling dt-bindings: timer: actions,owl-timer: convert to YAML clocksource/drivers/ralink: Add Ralink System Tick Counter driver clocksource/drivers/mips-gic-timer: Always use cluster 0 counter as clocksource clocksource/drivers/timer-ti-dm: Don't fail probe if int not found clocksource/drivers:sp804: Make user selectable clocksource/drivers/dw_apb: Remove unused dw_apb_clockevent functions hrtimers: Delete hrtimer_init_on_stack() alarmtimer: Switch to use hrtimer_setup() and hrtimer_setup_on_stack() io_uring: Switch to use hrtimer_setup_on_stack() sched/idle: Switch to use hrtimer_setup_on_stack() hrtimers: Delete hrtimer_init_sleeper_on_stack() wait: Switch to use hrtimer_setup_sleeper_on_stack() timers: Switch to use hrtimer_setup_sleeper_on_stack() net: pktgen: Switch to use hrtimer_setup_sleeper_on_stack() futex: Switch to use hrtimer_setup_sleeper_on_stack() fs/aio: Switch to use hrtimer_setup_sleeper_on_stack() ...
2024-11-19 16:35:06 -08:00