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2024-11-07io_uring/rsrc: pass 'struct io_ring_ctx' reference to rsrc helpersMing Lei
`io_rsrc_node` instance won't be shared among different io_uring ctxs, and its allocation 'ctx' is always same with the user's 'ctx', so it is safe to pass user 'ctx' reference to rsrc helpers. Even in io_clone_buffers(), `io_rsrc_node` instance is allocated actually for destination io_uring_ctx. Then io_rsrc_node_ctx() can be removed, and the 8 bytes `ctx` pointer will be removed from `io_rsrc_node` in the following patch. Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20241107110149.890530-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-11-02io_uring/rsrc: get rid of the empty node and dummy_ubufJens Axboe
The empty node was used as a placeholder for a sparse entry, but it didn't really solve any issues. The caller still has to check for whether it's the empty node or not, it may as well just check for a NULL return instead. The dummy_ubuf was used for a sparse buffer entry, but NULL will serve the same purpose there of ensuring an -EFAULT on attempted import. Just use NULL for a sparse node, regardless of whether or not it's a file or buffer resource. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-11-02io_uring/rsrc: add io_rsrc_node_lookup() helperJens Axboe
There are lots of spots open-coding this functionality, add a generic helper that does the node lookup in a speculation safe way. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-11-02io_uring/rsrc: unify file and buffer resource tablesJens Axboe
For files, there's nr_user_files/file_table/file_data, and buffers have nr_user_bufs/user_bufs/buf_data. There's no reason why file_table and file_data can't be the same thing, and ditto for the buffer side. That gets rid of more io_ring_ctx state that's in two spots rather than just being in one spot, as it should be. Put all the registered file data in one locations, and ditto on the buffer front. This also avoids having both io_rsrc_data->nodes being an allocated array, and ->user_bufs[] or ->file_table.nodes. There's no reason to have this information duplicated. Keep it in one spot, io_rsrc_data, along with how many resources are available. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-11-02io_uring/rsrc: add an empty io_rsrc_node for sparse buffer entriesJens Axboe
Rather than allocate an io_rsrc_node for an empty/sparse buffer entry, add a const entry that can be used for that. This just needs checking for writing the tag, and the put check needs to check for that sparse node rather than NULL for validity. This avoids allocating rsrc nodes for sparse buffer entries. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-11-02io_uring/rsrc: get rid of per-ring io_rsrc_node listJens Axboe
Work in progress, but get rid of the per-ring serialization of resource nodes, like registered buffers and files. Main issue here is that one node can otherwise hold up a bunch of other nodes from getting freed, which is especially a problem for file resource nodes and networked workloads where some descriptors may not see activity in a long time. As an example, instantiate an io_uring ring fd and create a sparse registered file table. Even 2 will do. Then create a socket and register it as fixed file 0, F0. The number of open files in the app is now 5, with 0/1/2 being the usual stdin/out/err, 3 being the ring fd, and 4 being the socket. Register this socket (eg "the listener") in slot 0 of the registered file table. Now add an operation on the socket that uses slot 0. Finally, loop N times, where each loop creates a new socket, registers said socket as a file, then unregisters the socket, and finally closes the socket. This is roughly similar to what a basic accept loop would look like. At the end of this loop, it's not unreasonable to expect that there would still be 5 open files. Each socket created and registered in the loop is also unregistered and closed. But since the listener socket registered first still has references to its resource node due to still being active, each subsequent socket unregistration is stuck behind it for reclaim. Hence 5 + N files are still open at that point, where N is awaiting the final put held up by the listener socket. Rewrite the io_rsrc_node handling to NOT rely on serialization. Struct io_kiocb now gets explicit resource nodes assigned, with each holding a reference to the parent node. A parent node is either of type FILE or BUFFER, which are the two types of nodes that exist. A request can have two nodes assigned, if it's using both registered files and buffers. Since request issue and task_work completion is both under the ring private lock, no atomics are needed to handle these references. It's a simple unlocked inc/dec. As before, the registered buffer or file table each hold a reference as well to the registered nodes. Final put of the node will remove the node and free the underlying resource, eg unmap the buffer or put the file. Outside of removing the stall in resource reclaim described above, it has the following advantages: 1) It's a lot simpler than the previous scheme, and easier to follow. No need to specific quiesce handling anymore. 2) There are no resource node allocations in the fast path, all of that happens at resource registration time. 3) The structs related to resource handling can all get simplified quite a bit, like io_rsrc_node and io_rsrc_data. io_rsrc_put can go away completely. 4) Handling of resource tags is much simpler, and doesn't require persistent storage as it can simply get assigned up front at registration time. Just copy them in one-by-one at registration time and assign to the resource node. The only real downside is that a request is now explicitly limited to pinning 2 resources, one file and one buffer, where before just assigning a resource node to a request would pin all of them. The upside is that it's easier to follow now, as an individual resource is explicitly referenced and assigned to the request. With this in place, the above mentioned example will be using exactly 5 files at the end of the loop, not N. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-10-29io_uring/splice: open code 2nd direct file assignmentJens Axboe
In preparation for not pinning the whole registered file table, open code the second potential direct file assignment. This will be handled by appropriate helpers in the future, for now just do it manually. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-12-12splice: return type ssize_t from all helpersAmir Goldstein
Not sure why some splice helpers return long, maybe historic reasons. Change them all to return ssize_t to conform to the splice methods and to the rest of the helpers. Suggested-by: Christian Brauner <brauner@kernel.org> Link: https://lore.kernel.org/r/20231208-horchen-helium-d3ec1535ede5@brauner/ Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231212094440.250945-2-amir73il@gmail.com Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-10io_uring/splice: use fput() directlyJens Axboe
No point in using io_file_put() here, as we need to check if it's a fixed file in the caller anyway. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: for requests that require async, force itDylan Yudaken
Some requests require being run async as they do not support non-blocking. Instead of trying to issue these requests, getting -EAGAIN and then queueing them for async issue, rather just force async upfront. Add WARN_ON_ONCE to make sure surprising code paths do not come up, however in those cases the bug would end up being a blocking io_uring_enter(2) which should not be critical. Signed-off-by: Dylan Yudaken <dylany@meta.com> Link: https://lore.kernel.org/r/20230127135227.3646353-3-dylany@meta.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-08-12io_uring: make io_kiocb_to_cmd() typesafeStefan Metzmacher
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>
2022-07-24io_uring: kill extra io_uring_types.h includesPavel Begunkov
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>
2022-07-24io_uring: split out splice related operationsJens Axboe
This splits out splice and tee support. Signed-off-by: Jens Axboe <axboe@kernel.dk>