kernel/linux.git/io_uring/rw.h, branch v6.19.11

io_uring: add wrapper type for io_req_tw_func_t arg

2025-11-03T15:31:26+00:00

In preparation for uring_cmd implementations to implement functions with the io_req_tw_func_t signature, introduce a wrapper struct io_tw_req to hide the struct io_kiocb * argument. The intention is for only the io_uring core to access the inner struct io_kiocb *. uring_cmd implementations should instead call a helper from io_uring/cmd.h to convert struct io_tw_req to struct io_uring_cmd *. Signed-off-by: Caleb Sander Mateos Signed-off-by: Jens Axboe

io_uring/kbuf: pass bgid to io_buffer_select()

2025-04-21T11:06:58+00:00

The current situation with buffer group id juggling is not ideal. req->buf_index first stores the bgid, then it's overwritten by a buffer id, and then it can get restored back no recycling / etc. It's not so easy to control, and it's not handled consistently across request types with receive requests saving and restoring the bgid it by hand. It's a prep patch that adds a buffer group id argument to io_buffer_select(). The caller will be responsible for stashing a copy somewhere and passing it into the function. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/a210d6427cc3f4f42271a6853274cd5a50e56820.1743437358.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

io_uring/rw: implement vectored registered rw

2025-03-07T16:07:29+00:00

Implement registered buffer vectored reads with new opcodes IORING_OP_WRITEV_FIXED and IORING_OP_READV_FIXED. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/d7c89eb481e870f598edc91cc66ff4d1e4ae3788.1741362889.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

io_uring: introduce struct iou_vec

2025-03-07T16:07:29+00:00

I need a convenient way to pass around and work with iovec+size pair, put them into a structure and makes use of it in rw.c Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/d39fadafc9e9047b0a292e5be6db3cf2f48bb1f7.1741362889.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

io_uring/rw: move fixed buffer import to issue path

2025-02-28T14:05:26+00:00

Registered buffers may depend on a linked command, which makes the prep path too early to import. Move to the issue path when the node is actually needed like all the other users of fixed buffers. Signed-off-by: Keith Busch Link: https://lore.kernel.org/r/20250227223916.143006-3-kbusch@meta.com Reviewed-by: Ming Lei Signed-off-by: Jens Axboe

io_uring: introduce type alias for io_tw_state

2025-02-17T12:34:50+00:00

In preparation for changing how io_tw_state is passed, introduce a type alias io_tw_token_t for struct io_tw_state *. This allows for changing the representation in one place, without having to update the many functions that just forward their struct io_tw_state * argument. Also add a comment to struct io_tw_state to explain its purpose. Signed-off-by: Caleb Sander Mateos Link: https://lore.kernel.org/r/20250217022511.1150145-1-csander@purestorage.com Signed-off-by: Jens Axboe

io_uring: get rid of alloc cache init_once handling

2025-01-23T18:32:28+00:00

init_once is called when an object doesn't come from the cache, and hence needs initial clearing of certain members. While the whole struct could get cleared by memset() in that case, a few of the cache members are large enough that this may cause unnecessary overhead if the caches used aren't large enough to satisfy the workload. For those cases, some churn of kmalloc+kfree is to be expected. Ensure that the 3 users that need clearing put the members they need cleared at the start of the struct, and wrap the rest of the struct in a struct group so the offset is known. While at it, improve the interaction with KASAN such that when/if KASAN writes to members inside the struct that should be retained over caching, it won't trip over itself. For rw and net, the retaining of the iovec over caching is disabled if KASAN is enabled. A helper will free and clear those members in that case. Signed-off-by: Jens Axboe

io_uring: introduce attributes for read/write and PI support

2024-12-23T15:17:16+00:00

Add the ability to pass additional attributes along with read/write. Application can prepare attibute specific information and pass its address using the SQE field: __u64 attr_ptr; Along with setting a mask indicating attributes being passed: __u64 attr_type_mask; Overall 64 attributes are allowed and currently one attribute 'IORING_RW_ATTR_FLAG_PI' is supported. With PI attribute, userspace can pass following information: - flags: integrity check flags IO_INTEGRITY_CHK_{GUARD/APPTAG/REFTAG} - len: length of PI/metadata buffer - addr: address of metadata buffer - seed: seed value for reftag remapping - app_tag: application defined 16b value Process this information to prepare uio_meta_descriptor and pass it down using kiocb->private. PI attribute is supported only for direct IO. Signed-off-by: Anuj Gupta Signed-off-by: Kanchan Joshi Link: https://lore.kernel.org/r/20241128112240.8867-7-anuj20.g@samsung.com Signed-off-by: Jens Axboe

io_uring/alloc_cache: switch to array based caching

2024-04-15T14:10:25+00:00

Currently lists are being used to manage this, but best practice is usually to have these in an array instead as that it cheaper to manage. Outside of that detail, games are also played with KASAN as the list is inside the cached entry itself. Finally, all users of this need a struct io_cache_entry embedded in their struct, which is union'ized with something else in there that isn't used across the free -> realloc cycle. Get rid of all of that, and simply have it be an array. This will not change the memory used, as we're just trading an 8-byte member entry for the per-elem array size. This reduces the overhead of the recycled allocations, and it reduces the amount of code code needed to support recycling to about half of what it currently is. Signed-off-by: Jens Axboe

io_uring/rw: add iovec recycling

2024-04-15T14:10:25+00:00

Let the io_async_rw hold on to the iovec and reuse it, rather than always allocate and free them. Also enables KASAN for the iovec entries, so that reuse can be detected even while they are in the cache. While doing so, shrink io_async_rw by getting rid of the bigger embedded fast iovec. Since iovecs are being recycled now, shrink it from 8 to 1. This reduces the io_async_rw size from 264 to 160 bytes, a 40% reduction. Signed-off-by: Jens Axboe