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* io_uring: fix error pbuf checkingPavel Begunkov2024-07-201-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | Syz reports a problem, which boils down to NULL vs IS_ERR inconsistent error handling in io_alloc_pbuf_ring(). KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:__io_remove_buffers+0xac/0x700 io_uring/kbuf.c:341 Call Trace: <TASK> io_put_bl io_uring/kbuf.c:378 [inline] io_destroy_buffers+0x14e/0x490 io_uring/kbuf.c:392 io_ring_ctx_free+0xa00/0x1070 io_uring/io_uring.c:2613 io_ring_exit_work+0x80f/0x8a0 io_uring/io_uring.c:2844 process_one_work kernel/workqueue.c:3231 [inline] process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312 worker_thread+0x86d/0xd40 kernel/workqueue.c:3390 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Cc: stable@vger.kernel.org Reported-by: syzbot+2074b1a3d447915c6f1c@syzkaller.appspotmail.com Fixes: 87585b05757dc ("io_uring/kbuf: use vm_insert_pages() for mmap'ed pbuf ring") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/c5f9df20560bd9830401e8e48abc029e7cfd9f5e.1721329239.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: add helpers for getting/peeking multiple buffersJens Axboe2024-04-221-3/+154
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Our provided buffer interface only allows selection of a single buffer. Add an API that allows getting/peeking multiple buffers at the same time. This is only implemented for the ring provided buffers. It could be added for the legacy provided buffers as well, but since it's strongly encouraged to use the new interface, let's keep it simpler and just provide it for the new API. The legacy interface will always just select a single buffer. There are two new main functions: io_buffers_select(), which selects up as many buffers as it can. The caller supplies the iovec array, and io_buffers_select() may allocate a bigger array if the 'out_len' being passed in is non-zero and bigger than what fits in the provided iovec. Buffers grabbed with this helper are permanently assigned. io_buffers_peek(), which works like io_buffers_select(), except they can be recycled, if needed. Callers using either of these functions should call io_put_kbufs() rather than io_put_kbuf() at completion time. The peek interface must be called with the ctx locked from peek to completion. This add a bit state for the request: - REQ_F_BUFFERS_COMMIT, which means that the the buffers have been peeked and should be committed to the buffer ring head when they are put as part of completion. Prior to this, req->buf_list was cleared to NULL when committed. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: remove dead defineJens Axboe2024-04-151-2/+0
| | | | | | We no longer use IO_BUFFER_LIST_BUF_PER_PAGE, kill it. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: move mapping/allocation helpers to a separate fileJens Axboe2024-04-151-0/+1
| | | | | | | | Move the related code from io_uring.c into memmap.c. No functional changes in this patch, just cleaning it up a bit now that the full transition is done. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: use unpin_user_pages() where appropriateJens Axboe2024-04-151-3/+2
| | | | | | | There are a few cases of open-rolled loops around unpin_user_page(), use the generic helper instead. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: use vm_insert_pages() for mmap'ed pbuf ringJens Axboe2024-04-151-108/+26
| | | | | | | | | | | | | | | | | | | Rather than use remap_pfn_range() for this and manually free later, switch to using vm_insert_page() and have it Just Work. This requires a bit of effort on the mmap lookup side, as the ctx uring_lock isn't held, which otherwise protects buffer_lists from being torn down, and it's not safe to grab from mmap context that would introduce an ABBA deadlock between the mmap lock and the ctx uring_lock. Instead, lookup the buffer_list under RCU, as the the list is RCU freed already. Use the existing reference count to determine whether it's possible to safely grab a reference to it (eg if it's not zero already), and drop that reference when done with the mapping. If the mmap reference is the last one, the buffer_list and the associated memory can go away, since the vma insertion has references to the inserted pages at that point. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: vmap pinned buffer ringJens Axboe2024-04-151-24/+15
| | | | | | | | This avoids needing to care about HIGHMEM, and it makes the buffer indexing easier as both ring provided buffer methods are now virtually mapped in a contigious fashion. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: hold io_buffer_list reference over mmapJens Axboe2024-04-021-8/+27
| | | | | | | | | | | | | If we look up the kbuf, ensure that it doesn't get unregistered until after we're done with it. Since we're inside mmap, we cannot safely use the io_uring lock. Rely on the fact that we can lookup the buffer list under RCU now and grab a reference to it, preventing it from being unregistered until we're done with it. The lookup returns the io_buffer_list directly with it referenced. Cc: stable@vger.kernel.org # v6.4+ Fixes: 5cf4f52e6d8a ("io_uring: free io_buffer_list entries via RCU") Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: protect io_buffer_list teardown with a referenceJens Axboe2024-04-021-4/+11
| | | | | | | | No functional changes in this patch, just in preparation for being able to keep the buffer list alive outside of the ctx->uring_lock. Cc: stable@vger.kernel.org # v6.4+ Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: get rid of bl->is_readyJens Axboe2024-04-021-8/+0
| | | | | | | | Now that xarray is being exclusively used for the buffer_list lookup, this check is no longer needed. Get rid of it and the is_ready member. Cc: stable@vger.kernel.org # v6.4+ Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: get rid of lower BGID listsJens Axboe2024-04-021-62/+8
| | | | | | | | Just rely on the xarray for any kind of bgid. This simplifies things, and it really doesn't bring us much, if anything. Cc: stable@vger.kernel.org # v6.4+ Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: rename is_mappedPavel Begunkov2024-03-131-10/+10
| | | | | | | | | | | In buffer lists we have ->is_mapped as well as ->is_mmap, it's pretty hard to stay sane double checking which one means what, and in the long run there is a high chance of an eventual bug. Rename ->is_mapped into ->is_buf_ring. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/c4838f4d8ad506ad6373f1c305aee2d2c1a89786.1710343154.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: rename REQ_F_PARTIAL_IO to REQ_F_BL_NO_RECYCLEJens Axboe2024-03-081-9/+0
| | | | | | | | | We only use the flag for this purpose, so rename it accordingly. This further prevents various other use cases of it, keeping it clean and consistent. Then we can also check it in one spot, when it's being attempted recycled, and remove some dead code in io_kbuf_recycle_ring(). Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: flag request if buffer pool is empty after buffer pickJens Axboe2024-02-271-2/+8
| | | | | | | | | | | | | | Normally we do an extra roundtrip for retries even if the buffer pool has depleted, as we don't check that upfront. Rather than add this check, have the buffer selection methods mark the request with REQ_F_BL_EMPTY if the used buffer group is out of buffers after this selection. This is very cheap to do once we're all the way inside there anyway, and it gives the caller a chance to make better decisions on how to proceed. For example, recv/recvmsg multishot could check this flag when it decides whether to keep receiving or not. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: cleanup passing back cflagsJens Axboe2024-02-081-10/+4
| | | | | | | | | | | | | | | We have various functions calculating the CQE cflags we need to pass back, but it's all the same everywhere. Make a number of the putting functions void, and just have the two main helps for this, io_put_kbuf() and io_put_kbuf_comp() calculate the actual mask and pass it back. While at it, cleanup how we put REQ_F_BUFFER_RING buffers. Before this change, we would call into __io_put_kbuf() only to go right back in to the header defined functions. As clearing this type of buffer is just re-assigning the buf_index and incrementing the head, this is very wasteful. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: add io_file_can_poll() helperJens Axboe2024-02-081-1/+1
| | | | | | | | | | This adds a flag to avoid dipping dereferencing file and then f_op to figure out if the file has a poll handler defined or not. We generally call this at least twice for networked workloads, and if using ring provided buffers, we do it on every buffer selection. Particularly the latter is troublesome, as it's otherwise a very fast operation. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: add method for returning provided buffer ring headJens Axboe2023-12-211-0/+26
| | | | | | | | | | | | | | | | | | The tail of the provided ring buffer is shared between the kernel and the application, but the head is private to the kernel as the application doesn't need to see it. However, this also prevents the application from knowing how many buffers the kernel has consumed. Usually this is fine, as the information is inherently racy in that the kernel could be consuming buffers continually, but for cleanup purposes it may be relevant to know how many buffers are still left in the ring. Add IORING_REGISTER_PBUF_STATUS which will return status for a given provided buffer ring. Right now it just returns the head, but space is reserved for more information later in, if needed. Link: https://github.com/axboe/liburing/discussions/1020 Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: check for buffer list readiness after NULL checkJens Axboe2023-12-051-2/+2
| | | | | | | | | Move the buffer list 'is_ready' check below the validity check for the buffer list for a given group. Fixes: 5cf4f52e6d8a ("io_uring: free io_buffer_list entries via RCU") Reported-by: Dan Carpenter <dan.carpenter@linaro.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: Fix an NULL vs IS_ERR() bug in io_alloc_pbuf_ring()Dan Carpenter2023-12-051-2/+2
| | | | | | | | | | The io_mem_alloc() function returns error pointers, not NULL. Update the check accordingly. Fixes: b10b73c102a2 ("io_uring/kbuf: recycle freed mapped buffer ring entries") Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> Link: https://lore.kernel.org/r/5ed268d3-a997-4f64-bd71-47faa92101ab@moroto.mountain Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: free io_buffer_list entries via RCUJens Axboe2023-11-281-13/+51
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | mmap_lock nests under uring_lock out of necessity, as we may be doing user copies with uring_lock held. However, for mmap of provided buffer rings, we attempt to grab uring_lock with mmap_lock already held from do_mmap(). This makes lockdep, rightfully, complain: WARNING: possible circular locking dependency detected 6.7.0-rc1-00009-gff3337ebaf94-dirty #4438 Not tainted ------------------------------------------------------ buf-ring.t/442 is trying to acquire lock: ffff00020e1480a8 (&ctx->uring_lock){+.+.}-{3:3}, at: io_uring_validate_mmap_request.isra.0+0x4c/0x140 but task is already holding lock: ffff0000dc226190 (&mm->mmap_lock){++++}-{3:3}, at: vm_mmap_pgoff+0x124/0x264 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&mm->mmap_lock){++++}-{3:3}: __might_fault+0x90/0xbc io_register_pbuf_ring+0x94/0x488 __arm64_sys_io_uring_register+0x8dc/0x1318 invoke_syscall+0x5c/0x17c el0_svc_common.constprop.0+0x108/0x130 do_el0_svc+0x2c/0x38 el0_svc+0x4c/0x94 el0t_64_sync_handler+0x118/0x124 el0t_64_sync+0x168/0x16c -> #0 (&ctx->uring_lock){+.+.}-{3:3}: __lock_acquire+0x19a0/0x2d14 lock_acquire+0x2e0/0x44c __mutex_lock+0x118/0x564 mutex_lock_nested+0x20/0x28 io_uring_validate_mmap_request.isra.0+0x4c/0x140 io_uring_mmu_get_unmapped_area+0x3c/0x98 get_unmapped_area+0xa4/0x158 do_mmap+0xec/0x5b4 vm_mmap_pgoff+0x158/0x264 ksys_mmap_pgoff+0x1d4/0x254 __arm64_sys_mmap+0x80/0x9c invoke_syscall+0x5c/0x17c el0_svc_common.constprop.0+0x108/0x130 do_el0_svc+0x2c/0x38 el0_svc+0x4c/0x94 el0t_64_sync_handler+0x118/0x124 el0t_64_sync+0x168/0x16c From that mmap(2) path, we really just need to ensure that the buffer list doesn't go away from underneath us. For the lower indexed entries, they never go away until the ring is freed and we can always sanely reference those as long as the caller has a file reference. For the higher indexed ones in our xarray, we just need to ensure that the buffer list remains valid while we return the address of it. Free the higher indexed io_buffer_list entries via RCU. With that we can avoid needing ->uring_lock inside mmap(2), and simply hold the RCU read lock around the buffer list lookup and address check. To ensure that the arrayed lookup either returns a valid fully formulated entry via RCU lookup, add an 'is_ready' flag that we access with store and release memory ordering. This isn't needed for the xarray lookups, but doesn't hurt either. Since this isn't a fast path, retain it across both types. Similarly, for the allocated array inside the ctx, ensure we use the proper load/acquire as setup could in theory be running in parallel with mmap. While in there, add a few lockdep checks for documentation purposes. Cc: stable@vger.kernel.org Fixes: c56e022c0a27 ("io_uring: add support for user mapped provided buffer ring") Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: prune deferred locked cache when tearing downJens Axboe2023-11-281-0/+8
| | | | | | | | | | | | | | We used to just use our page list for final teardown, which would ensure that we got all the buffers, even the ones that were not on the normal cached list. But while moving to slab for the io_buffers, we know only prune this list, not the deferred locked list that we have. This can cause a leak of memory, if the workload ends up using the intermediate locked list. Fix this by always pruning both lists when tearing down. Fixes: b3a4dbc89d40 ("io_uring/kbuf: Use slab for struct io_buffer objects") Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: recycle freed mapped buffer ring entriesJens Axboe2023-11-281-11/+66
| | | | | | | | | | | | | | Right now we stash any potentially mmap'ed provided ring buffer range for freeing at release time, regardless of when they get unregistered. Since we're keeping track of these ranges anyway, keep track of their registration state as well, and use that to recycle ranges when appropriate rather than always allocate new ones. The lookup is a basic scan of entries, checking for the best matching free entry. Fixes: c392cbecd8ec ("io_uring/kbuf: defer release of mapped buffer rings") Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: defer release of mapped buffer ringsJens Axboe2023-11-281-5/+39
| | | | | | | | | | | | | | | | If a provided buffer ring is setup with IOU_PBUF_RING_MMAP, then the kernel allocates the memory for it and the application is expected to mmap(2) this memory. However, io_uring uses remap_pfn_range() for this operation, so we cannot rely on normal munmap/release on freeing them for us. Stash an io_buf_free entry away for each of these, if any, and provide a helper to free them post ->release(). Cc: stable@vger.kernel.org Fixes: c56e022c0a27 ("io_uring: add support for user mapped provided buffer ring") Reported-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: indicate if io_kbuf_recycle did recycle anythingDylan Yudaken2023-11-061-3/+3
| | | | | | | | | It can be useful to know if io_kbuf_recycle did actually recycle the buffer on the request, or if it left the request alone. Signed-off-by: Dylan Yudaken <dyudaken@gmail.com> Link: https://lore.kernel.org/r/20231106203909.197089-2-dyudaken@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Merge tag 'for-6.7/io_uring-2023-10-30' of git://git.kernel.dk/linuxLinus Torvalds2023-11-011-25/+33
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull io_uring updates from Jens Axboe: "This contains the core io_uring updates, of which there are not many, and adds support for using WAITID through io_uring and hence not needing to block on these kinds of events. Outside of that, tweaks to the legacy provided buffer handling and some cleanups related to cancelations for uring_cmd support" * tag 'for-6.7/io_uring-2023-10-30' of git://git.kernel.dk/linux: io_uring/poll: use IOU_F_TWQ_LAZY_WAKE for wakeups io_uring/kbuf: Use slab for struct io_buffer objects io_uring/kbuf: Allow the full buffer id space for provided buffers io_uring/kbuf: Fix check of BID wrapping in provided buffers io_uring/rsrc: cleanup io_pin_pages() io_uring: cancelable uring_cmd io_uring: retain top 8bits of uring_cmd flags for kernel internal use io_uring: add IORING_OP_WAITID support exit: add internal include file with helpers exit: add kernel_waitid_prepare() helper exit: move core of do_wait() into helper exit: abstract out should_wake helper for child_wait_callback() io_uring/rw: add support for IORING_OP_READ_MULTISHOT io_uring/rw: mark readv/writev as vectored in the opcode definition io_uring/rw: split io_read() into a helper
| * io_uring/kbuf: Use slab for struct io_buffer objectsGabriel Krisman Bertazi2023-10-051-21/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The allocation of struct io_buffer for metadata of provided buffers is done through a custom allocator that directly gets pages and fragments them. But, slab would do just fine, as this is not a hot path (in fact, it is a deprecated feature) and, by keeping a custom allocator implementation we lose benefits like tracking, poisoning, sanitizers. Finally, the custom code is more complex and requires keeping the list of pages in struct ctx for no good reason. This patch cleans this path up and just uses slab. I microbenchmarked it by forcing the allocation of a large number of objects with the least number of io_uring commands possible (keeping nbufs=USHRT_MAX), with and without the patch. There is a slight increase in time spent in the allocation with slab, of course, but even when allocating to system resources exhaustion, which is not very realistic and happened around 1/2 billion provided buffers for me, it wasn't a significant hit in system time. Specially if we think of a real-world scenario, an application doing register/unregister of provided buffers will hit ctx->io_buffers_cache more often than actually going to slab. Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de> Link: https://lore.kernel.org/r/20231005000531.30800-4-krisman@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * io_uring/kbuf: Allow the full buffer id space for provided buffersGabriel Krisman Bertazi2023-10-051-4/+7
| | | | | | | | | | | | | | | | | | | | | | | | nbufs tracks the number of buffers and not the last bgid. In 16-bit, we have 2^16 valid buffers, but the check mistakenly rejects the last bid. Let's fix it to make the interface consistent with the documentation. Fixes: ddf0322db79c ("io_uring: add IORING_OP_PROVIDE_BUFFERS") Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de> Link: https://lore.kernel.org/r/20231005000531.30800-3-krisman@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * io_uring/kbuf: Fix check of BID wrapping in provided buffersGabriel Krisman Bertazi2023-10-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 3851d25c75ed0 ("io_uring: check for rollover of buffer ID when providing buffers") introduced a check to prevent wrapping the BID counter when sqe->off is provided, but it's off-by-one too restrictive, rejecting the last possible BID (65534). i.e., the following fails with -EINVAL. io_uring_prep_provide_buffers(sqe, addr, size, 0xFFFF, 0, 0); Fixes: 3851d25c75ed ("io_uring: check for rollover of buffer ID when providing buffers") Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de> Link: https://lore.kernel.org/r/20231005000531.30800-2-krisman@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | io_uring/kbuf: don't allow registered buffer rings on highmem pagesJens Axboe2023-10-031-8/+19
|/ | | | | | | | | | | | | | | | | | | | syzbot reports that registering a mapped buffer ring on arm32 can trigger an OOPS. Registered buffer rings have two modes, one of them is the application passing in the memory that the buffer ring should reside in. Once those pages are mapped, we use page_address() to get a virtual address. This will obviously fail on highmem pages, which aren't mapped. Add a check if we have any highmem pages after mapping, and fail the attempt to register a provided buffer ring if we do. This will return the same error as kernels that don't support provided buffer rings to begin with. Link: https://lore.kernel.org/io-uring/000000000000af635c0606bcb889@google.com/ Fixes: c56e022c0a27 ("io_uring: add support for user mapped provided buffer ring") Cc: stable@vger.kernel.org Reported-by: syzbot+2113e61b8848fa7951d8@syzkaller.appspotmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: stop calling free_compound_page()Matthew Wilcox (Oracle)2023-08-211-5/+1
| | | | | | | | | | | | | | | | | | | | Patch series "Remove _folio_dtor and _folio_order", v2. This patch (of 13): folio_put() is the standard way to write this, and it's not appreciably slower. This is an enabling patch for removing free_compound_page() entirely. Link: https://lkml.kernel.org/r/20230816151201.3655946-1-willy@infradead.org Link: https://lkml.kernel.org/r/20230816151201.3655946-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Jens Axboe <axboe@kernel.dk> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Yanteng Si <siyanteng@loongson.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* Merge tag 'for-6.4/io_uring-2023-04-21' of git://git.kernel.dk/linuxLinus Torvalds2023-04-261-36/+124
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull io_uring updates from Jens Axboe: - Cleanup of the io-wq per-node mapping, notably getting rid of it so we just have a single io_wq entry per ring (Breno) - Followup to the above, move accounting to io_wq as well and completely drop struct io_wqe (Gabriel) - Enable KASAN for the internal io_uring caches (Breno) - Add support for multishot timeouts. Some applications use timeouts to wake someone waiting on completion entries, and this makes it a bit easier to just have a recurring timer rather than needing to rearm it every time (David) - Support archs that have shared cache coloring between userspace and the kernel, and hence have strict address requirements for mmap'ing the ring into userspace. This should only be parisc/hppa. (Helge, me) - XFS has supported O_DIRECT writes without needing to lock the inode exclusively for a long time, and ext4 now supports it as well. This is true for the common cases of not extending the file size. Flag the fs as having that feature, and utilize that to avoid serializing those writes in io_uring (me) - Enable completion batching for uring commands (me) - Revert patch adding io_uring restriction to what can be GUP mapped or not. This does not belong in io_uring, as io_uring isn't really special in this regard. Since this is also getting in the way of cleanups and improvements to the GUP code, get rid of if (me) - A few series greatly reducing the complexity of registered resources, like buffers or files. Not only does this clean up the code a lot, the simplified code is also a LOT more efficient (Pavel) - Series optimizing how we wait for events and run task_work related to it (Pavel) - Fixes for file/buffer unregistration with DEFER_TASKRUN (Pavel) - Misc cleanups and improvements (Pavel, me) * tag 'for-6.4/io_uring-2023-04-21' of git://git.kernel.dk/linux: (71 commits) Revert "io_uring/rsrc: disallow multi-source reg buffers" io_uring: add support for multishot timeouts io_uring/rsrc: disassociate nodes and rsrc_data io_uring/rsrc: devirtualise rsrc put callbacks io_uring/rsrc: pass node to io_rsrc_put_work() io_uring/rsrc: inline io_rsrc_put_work() io_uring/rsrc: add empty flag in rsrc_node io_uring/rsrc: merge nodes and io_rsrc_put io_uring/rsrc: infer node from ctx on io_queue_rsrc_removal io_uring/rsrc: remove unused io_rsrc_node::llist io_uring/rsrc: refactor io_queue_rsrc_removal io_uring/rsrc: simplify single file node switching io_uring/rsrc: clean up __io_sqe_buffers_update() io_uring/rsrc: inline switch_start fast path io_uring/rsrc: remove rsrc_data refs io_uring/rsrc: fix DEFER_TASKRUN rsrc quiesce io_uring/rsrc: use wq for quiescing io_uring/rsrc: refactor io_rsrc_ref_quiesce io_uring/rsrc: remove io_rsrc_node::done io_uring/rsrc: use nospec'ed indexes ...
| * io_uring/kbuf: remove extra ->buf_ring null checkPavel Begunkov2023-04-121-8/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The kernel test robot complains about __io_remove_buffers(). io_uring/kbuf.c:221 __io_remove_buffers() warn: variable dereferenced before check 'bl->buf_ring' (see line 219) That check is not needed as ->buf_ring will always be set, so we can remove it and so silence the warning. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/9a632bbf749d9d911e605255652ce08d18e7d2c6.1681210788.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * io_uring/kbuf: disallow mapping a badly aligned provided ring bufferJens Axboe2023-04-031-0/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On at least parisc, we have strict requirements on how we virtually map an address that is shared between the application and the kernel. On these platforms, IOU_PBUF_RING_MMAP should be used when setting up a shared ring buffer for provided buffers. If the application is mapping these pages and asking the kernel to pin+map them as well, then we have no control over what virtual address we get in the kernel. For that case, do a sanity check if SHM_COLOUR is defined, and disallow the mapping request. The application must fall back to using IOU_PBUF_RING_MMAP for this case, and liburing will do that transparently with the set of helpers that it has. Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * io_uring: add support for user mapped provided buffer ringJens Axboe2023-04-031-23/+76
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The ring mapped provided buffer rings rely on the application allocating the memory for the ring, and then the kernel will map it. This generally works fine, but runs into issues on some architectures where we need to be able to ensure that the kernel and application virtual address for the ring play nicely together. This at least impacts architectures that set SHM_COLOUR, but potentially also anyone setting SHMLBA. To use this variant of ring provided buffers, the application need not allocate any memory for the ring. Instead the kernel will do so, and the allocation must subsequently call mmap(2) on the ring with the offset set to: IORING_OFF_PBUF_RING | (bgid << IORING_OFF_PBUF_SHIFT) to get a virtual address for the buffer ring. Normally the application would allocate a suitable piece of memory (and correctly aligned) and simply pass that in via io_uring_buf_reg.ring_addr and the kernel would map it. Outside of the setup differences, the kernel allocate + user mapped provided buffer ring works exactly the same. Acked-by: Helge Deller <deller@gmx.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * io_uring/kbuf: rename struct io_uring_buf_reg 'pad' to'flags'Jens Axboe2023-04-031-2/+6
| | | | | | | | | | | | | | | | In preparation for allowing flags to be set for registration, rename the padding and use it for that. Acked-by: Helge Deller <deller@gmx.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * io_uring/kbuf: add buffer_list->is_mapped memberJens Axboe2023-04-031-6/+8
| | | | | | | | | | | | | | | | | | Rather than rely on checking buffer_list->buf_pages or ->buf_nr_pages, add a separate member that tracks if this is a ring mapped provided buffer list or not. Acked-by: Helge Deller <deller@gmx.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * io_uring/kbuf: move pinning of provided buffer ring into helperJens Axboe2023-04-031-12/+25
| | | | | | | | | | | | | | | | | | | | | | In preparation for allowing the kernel to allocate the provided buffer rings and have the application mmap it instead, abstract out the current method of pinning and mapping the user allocated ring. No functional changes intended in this patch. Acked-by: Helge Deller <deller@gmx.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | io_uring: fix memory leak when removing provided buffersWojciech Lukowicz2023-04-011-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | When removing provided buffers, io_buffer structs are not being disposed of, leading to a memory leak. They can't be freed individually, because they are allocated in page-sized groups. They need to be added to some free list instead, such as io_buffers_cache. All callers already hold the lock protecting it, apart from when destroying buffers, so had to extend the lock there. Fixes: cc3cec8367cb ("io_uring: speedup provided buffer handling") Signed-off-by: Wojciech Lukowicz <wlukowicz01@gmail.com> Link: https://lore.kernel.org/r/20230401195039.404909-2-wlukowicz01@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | io_uring: fix return value when removing provided buffersWojciech Lukowicz2023-04-011-2/+0
|/ | | | | | | | | | | | | | | | When a request to remove buffers is submitted, and the given number to be removed is larger than available in the specified buffer group, the resulting CQE result will be the number of removed buffers + 1, which is 1 more than it should be. Previously, the head was part of the list and it got removed after the loop, so the increment was needed. Now, the head is not an element of the list, so the increment shouldn't be there anymore. Fixes: dbc7d452e7cf ("io_uring: manage provided buffers strictly ordered") Signed-off-by: Wojciech Lukowicz <wlukowicz01@gmail.com> Link: https://lore.kernel.org/r/20230401195039.404909-2-wlukowicz01@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: fix size calculation when registering buf ringWojciech Lukowicz2023-02-221-1/+1
| | | | | | | | | | | | | | | | | | | | | | Using struct_size() to calculate the size of io_uring_buf_ring will sum the size of the struct and of the bufs array. However, the struct's fields are overlaid with the array making the calculated size larger than it should be. When registering a ring with N * PAGE_SIZE / sizeof(struct io_uring_buf) entries, i.e. with fully filled pages, the calculated size will span one more page than it should and io_uring will try to pin the following page. Depending on how the application allocated the ring, it might succeed using an unrelated page or fail returning EFAULT. The size of the ring should be the product of ring_entries and the size of io_uring_buf, i.e. the size of the bufs array only. Fixes: c7fb19428d67 ("io_uring: add support for ring mapped supplied buffers") Signed-off-by: Wojciech Lukowicz <wlukowicz01@gmail.com> Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de> Link: https://lore.kernel.org/r/20230218184141.70891-1-wlukowicz01@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: don't use complete_post in kbufPavel Begunkov2022-11-251-9/+5
| | | | | | | | | | | Now we're handling IOPOLL completions more generically, get rid uses of _post() and send requests through the normal path. It may have some extra mertis performance wise, but we don't care much as there is a better interface for selected buffers. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/4deded706587f55b006dc33adf0c13cfc3b2319f.1669310258.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: iopoll protect complete_postPavel Begunkov2022-11-231-2/+2
| | | | | | | | | | io_req_complete_post() may be used by iopoll enabled rings, grab locks in this case. That requires to pass issue_flags to propagate the locking state. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/cc6d854065c57c838ca8e8806f707a226b70fd2d.1669203009.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: check for rollover of buffer ID when providing buffersJens Axboe2022-11-101-0/+2
| | | | | | | | | | | | | | | | | | We already check if the chosen starting offset for the buffer IDs fit within an unsigned short, as 65535 is the maximum value for a provided buffer. But if the caller asks to add N buffers at offset M, and M + N would exceed the size of the unsigned short, we simply add buffers with wrapping around the ID. This is not necessarily a bug and could in fact be a valid use case, but it seems confusing and inconsistent with the initial check for starting offset. Let's check for wrap consistently, and error the addition if we do need to wrap. Reported-by: Olivier Langlois <olivier@trillion01.com> Link: https://github.com/axboe/liburing/issues/726 Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: make io_kiocb_to_cmd() typesafeStefan Metzmacher2022-08-121-4/+4
| | | | | | | | | We need to make sure (at build time) that struct io_cmd_data is not casted to a structure that's larger. Signed-off-by: Stefan Metzmacher <metze@samba.org> Link: https://lore.kernel.org/r/c024cdf25ae19fc0319d4180e2298bade8ed17b8.1660201408.git.metze@samba.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: mem-account pbuf bucketsPavel Begunkov2022-08-041-1/+1
| | | | | | | | | | | Potentially, someone may create as many pbuf bucket as there are indexes in an xarray without any other restrictions bounding our memory usage, put memory needed for the buckets under memory accounting. Cc: <stable@vger.kernel.org> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/d34c452e45793e978d26e2606211ec9070d329ea.1659622312.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: allow 0 length for buffer selectDylan Yudaken2022-07-241-2/+2
| | | | | | | | If user gives 0 for length, we can set it from the available buffer size. Signed-off-by: Dylan Yudaken <dylany@fb.com> Link: https://lore.kernel.org/r/20220630091231.1456789-2-dylany@fb.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: kbuf: inline io_kbuf_recycle_ring()Hao Xu2022-07-241-28/+0
| | | | | | | | | Make io_kbuf_recycle_ring() inline since it is the fast path of provided buffer. Signed-off-by: Hao Xu <howeyxu@tencent.com> Link: https://lore.kernel.org/r/20220623130126.179232-1-hao.xu@linux.dev Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: kbuf: kill __io_kbuf_recycle()Hao Xu2022-07-241-29/+42
| | | | | | | | | __io_kbuf_recycle() is only called in io_kbuf_recycle(). Kill it and tweak the code so that the legacy pbuf and ring pbuf code become clear Signed-off-by: Hao Xu <howeyxu@tencent.com> Link: https://lore.kernel.org/r/20220622055551.642370-1-hao.xu@linux.dev Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: kill extra io_uring_types.h includesPavel Begunkov2022-07-241-1/+0
| | | | | | | | | | io_uring/io_uring.h already includes io_uring_types.h, no need to include it every time. Kill it in a bunch of places, it prepares us for following patches. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/94d8c943fbe0ef949981c508ddcee7fc1c18850f.1655384063.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: kbuf: add comments for some tricky codeHao Xu2022-07-241-6/+14
| | | | | | | | | | Add comments to explain why it is always under uring lock when incrementing head in __io_kbuf_recycle. And rectify one comemnt about kbuf consuming in iowq case. Signed-off-by: Hao Xu <howeyxu@tencent.com> Link: https://lore.kernel.org/r/20220617050429.94293-1-hao.xu@linux.dev Signed-off-by: Jens Axboe <axboe@kernel.dk>
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