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6e73dffbb9
From recently io_uring provides an option to allocate a file index for operation registering fixed files. However, it's utterly unusable with mixed approaches when for a part of files the userspace knows better where to place it, as it may race and users don't have any sane way to pick a slot and hoping it will not be taken. Let the userspace to register a range of fixed file slots in which the auto-allocation happens. The use case is splittting the fixed table in two parts, where on of them is used for auto-allocation and another for slot-specified operations. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/66ab0394e436f38437cf7c44676e1920d09687ad.1656154403.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
88 lines
2.5 KiB
C
88 lines
2.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#ifndef IOU_FILE_TABLE_H
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#define IOU_FILE_TABLE_H
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#include <linux/file.h>
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#include <linux/io_uring_types.h>
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/*
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* FFS_SCM is only available on 64-bit archs, for 32-bit we just define it as 0
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* and define IO_URING_SCM_ALL. For this case, we use SCM for all files as we
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* can't safely always dereference the file when the task has exited and ring
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* cleanup is done. If a file is tracked and part of SCM, then unix gc on
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* process exit may reap it before __io_sqe_files_unregister() is run.
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*/
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#define FFS_NOWAIT 0x1UL
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#define FFS_ISREG 0x2UL
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#if defined(CONFIG_64BIT)
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#define FFS_SCM 0x4UL
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#else
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#define IO_URING_SCM_ALL
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#define FFS_SCM 0x0UL
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#endif
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#define FFS_MASK ~(FFS_NOWAIT|FFS_ISREG|FFS_SCM)
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bool io_alloc_file_tables(struct io_file_table *table, unsigned nr_files);
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void io_free_file_tables(struct io_file_table *table);
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int io_fixed_fd_install(struct io_kiocb *req, unsigned int issue_flags,
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struct file *file, unsigned int file_slot);
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int __io_fixed_fd_install(struct io_ring_ctx *ctx, struct file *file,
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unsigned int file_slot);
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int io_fixed_fd_remove(struct io_ring_ctx *ctx, unsigned int offset);
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int io_register_file_alloc_range(struct io_ring_ctx *ctx,
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struct io_uring_file_index_range __user *arg);
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unsigned int io_file_get_flags(struct file *file);
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static inline void io_file_bitmap_clear(struct io_file_table *table, int bit)
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{
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__clear_bit(bit, table->bitmap);
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table->alloc_hint = bit;
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}
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static inline void io_file_bitmap_set(struct io_file_table *table, int bit)
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{
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WARN_ON_ONCE(test_bit(bit, table->bitmap));
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__set_bit(bit, table->bitmap);
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table->alloc_hint = bit + 1;
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}
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static inline struct io_fixed_file *
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io_fixed_file_slot(struct io_file_table *table, unsigned i)
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{
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return &table->files[i];
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}
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static inline struct file *io_file_from_index(struct io_file_table *table,
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int index)
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{
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struct io_fixed_file *slot = io_fixed_file_slot(table, index);
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return (struct file *) (slot->file_ptr & FFS_MASK);
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}
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static inline void io_fixed_file_set(struct io_fixed_file *file_slot,
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struct file *file)
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{
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unsigned long file_ptr = (unsigned long) file;
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file_ptr |= io_file_get_flags(file);
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file_slot->file_ptr = file_ptr;
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}
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static inline void io_reset_alloc_hint(struct io_ring_ctx *ctx)
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{
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ctx->file_table.alloc_hint = ctx->file_alloc_start;
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}
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static inline void io_file_table_set_alloc_range(struct io_ring_ctx *ctx,
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unsigned off, unsigned len)
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{
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ctx->file_alloc_start = off;
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ctx->file_alloc_end = off + len;
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io_reset_alloc_hint(ctx);
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}
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#endif
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