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- /* SPDX-License-Identifier: GPL-2.0-or-later */
- /*
- * Berkeley style UIO structures - Alan Cox 1994.
- */
- #ifndef __LINUX_UIO_H
- #define __LINUX_UIO_H
- #include <linux/kernel.h>
- #include <linux/thread_info.h>
- #include <uapi/linux/uio.h>
- struct page;
- struct pipe_inode_info;
- struct kvec {
- void *iov_base; /* and that should *never* hold a userland pointer */
- size_t iov_len;
- };
- enum iter_type {
- /* iter types */
- ITER_IOVEC = 4,
- ITER_KVEC = 8,
- ITER_BVEC = 16,
- ITER_PIPE = 32,
- ITER_DISCARD = 64,
- };
- struct iov_iter {
- /*
- * Bit 0 is the read/write bit, set if we're writing.
- * Bit 1 is the BVEC_FLAG_NO_REF bit, set if type is a bvec and
- * the caller isn't expecting to drop a page reference when done.
- */
- unsigned int type;
- size_t iov_offset;
- size_t count;
- union {
- const struct iovec *iov;
- const struct kvec *kvec;
- const struct bio_vec *bvec;
- struct pipe_inode_info *pipe;
- };
- union {
- unsigned long nr_segs;
- struct {
- unsigned int head;
- unsigned int start_head;
- };
- };
- };
- static inline enum iter_type iov_iter_type(const struct iov_iter *i)
- {
- return i->type & ~(READ | WRITE);
- }
- static inline bool iter_is_iovec(const struct iov_iter *i)
- {
- return iov_iter_type(i) == ITER_IOVEC;
- }
- static inline bool iov_iter_is_kvec(const struct iov_iter *i)
- {
- return iov_iter_type(i) == ITER_KVEC;
- }
- static inline bool iov_iter_is_bvec(const struct iov_iter *i)
- {
- return iov_iter_type(i) == ITER_BVEC;
- }
- static inline bool iov_iter_is_pipe(const struct iov_iter *i)
- {
- return iov_iter_type(i) == ITER_PIPE;
- }
- static inline bool iov_iter_is_discard(const struct iov_iter *i)
- {
- return iov_iter_type(i) == ITER_DISCARD;
- }
- static inline unsigned char iov_iter_rw(const struct iov_iter *i)
- {
- return i->type & (READ | WRITE);
- }
- /*
- * Total number of bytes covered by an iovec.
- *
- * NOTE that it is not safe to use this function until all the iovec's
- * segment lengths have been validated. Because the individual lengths can
- * overflow a size_t when added together.
- */
- static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
- {
- unsigned long seg;
- size_t ret = 0;
- for (seg = 0; seg < nr_segs; seg++)
- ret += iov[seg].iov_len;
- return ret;
- }
- static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
- {
- return (struct iovec) {
- .iov_base = iter->iov->iov_base + iter->iov_offset,
- .iov_len = min(iter->count,
- iter->iov->iov_len - iter->iov_offset),
- };
- }
- size_t iov_iter_copy_from_user_atomic(struct page *page,
- struct iov_iter *i, unsigned long offset, size_t bytes);
- void iov_iter_advance(struct iov_iter *i, size_t bytes);
- void iov_iter_revert(struct iov_iter *i, size_t bytes);
- int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
- size_t iov_iter_single_seg_count(const struct iov_iter *i);
- size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
- struct iov_iter *i);
- size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
- struct iov_iter *i);
- size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i);
- size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i);
- bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i);
- size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i);
- bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i);
- static __always_inline __must_check
- size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
- {
- if (unlikely(!check_copy_size(addr, bytes, true)))
- return 0;
- else
- return _copy_to_iter(addr, bytes, i);
- }
- static __always_inline __must_check
- size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
- {
- if (unlikely(!check_copy_size(addr, bytes, false)))
- return 0;
- else
- return _copy_from_iter(addr, bytes, i);
- }
- static __always_inline __must_check
- bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i)
- {
- if (unlikely(!check_copy_size(addr, bytes, false)))
- return false;
- else
- return _copy_from_iter_full(addr, bytes, i);
- }
- static __always_inline __must_check
- size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
- {
- if (unlikely(!check_copy_size(addr, bytes, false)))
- return 0;
- else
- return _copy_from_iter_nocache(addr, bytes, i);
- }
- static __always_inline __must_check
- bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
- {
- if (unlikely(!check_copy_size(addr, bytes, false)))
- return false;
- else
- return _copy_from_iter_full_nocache(addr, bytes, i);
- }
- #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
- /*
- * Note, users like pmem that depend on the stricter semantics of
- * copy_from_iter_flushcache() than copy_from_iter_nocache() must check for
- * IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) before assuming that the
- * destination is flushed from the cache on return.
- */
- size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i);
- #else
- #define _copy_from_iter_flushcache _copy_from_iter_nocache
- #endif
- #ifdef CONFIG_ARCH_HAS_COPY_MC
- size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i);
- #else
- #define _copy_mc_to_iter _copy_to_iter
- #endif
- static __always_inline __must_check
- size_t copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i)
- {
- if (unlikely(!check_copy_size(addr, bytes, false)))
- return 0;
- else
- return _copy_from_iter_flushcache(addr, bytes, i);
- }
- static __always_inline __must_check
- size_t copy_mc_to_iter(void *addr, size_t bytes, struct iov_iter *i)
- {
- if (unlikely(!check_copy_size(addr, bytes, true)))
- return 0;
- else
- return _copy_mc_to_iter(addr, bytes, i);
- }
- size_t iov_iter_zero(size_t bytes, struct iov_iter *);
- unsigned long iov_iter_alignment(const struct iov_iter *i);
- unsigned long iov_iter_gap_alignment(const struct iov_iter *i);
- void iov_iter_init(struct iov_iter *i, unsigned int direction, const struct iovec *iov,
- unsigned long nr_segs, size_t count);
- void iov_iter_kvec(struct iov_iter *i, unsigned int direction, const struct kvec *kvec,
- unsigned long nr_segs, size_t count);
- void iov_iter_bvec(struct iov_iter *i, unsigned int direction, const struct bio_vec *bvec,
- unsigned long nr_segs, size_t count);
- void iov_iter_pipe(struct iov_iter *i, unsigned int direction, struct pipe_inode_info *pipe,
- size_t count);
- void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count);
- ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
- size_t maxsize, unsigned maxpages, size_t *start);
- ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages,
- size_t maxsize, size_t *start);
- int iov_iter_npages(const struct iov_iter *i, int maxpages);
- const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags);
- static inline size_t iov_iter_count(const struct iov_iter *i)
- {
- return i->count;
- }
- /*
- * Cap the iov_iter by given limit; note that the second argument is
- * *not* the new size - it's upper limit for such. Passing it a value
- * greater than the amount of data in iov_iter is fine - it'll just do
- * nothing in that case.
- */
- static inline void iov_iter_truncate(struct iov_iter *i, u64 count)
- {
- /*
- * count doesn't have to fit in size_t - comparison extends both
- * operands to u64 here and any value that would be truncated by
- * conversion in assignement is by definition greater than all
- * values of size_t, including old i->count.
- */
- if (i->count > count)
- i->count = count;
- }
- /*
- * reexpand a previously truncated iterator; count must be no more than how much
- * we had shrunk it.
- */
- static inline void iov_iter_reexpand(struct iov_iter *i, size_t count)
- {
- i->count = count;
- }
- struct csum_state {
- __wsum csum;
- size_t off;
- };
- size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csstate, struct iov_iter *i);
- size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
- bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
- size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp,
- struct iov_iter *i);
- struct iovec *iovec_from_user(const struct iovec __user *uvector,
- unsigned long nr_segs, unsigned long fast_segs,
- struct iovec *fast_iov, bool compat);
- ssize_t import_iovec(int type, const struct iovec __user *uvec,
- unsigned nr_segs, unsigned fast_segs, struct iovec **iovp,
- struct iov_iter *i);
- ssize_t __import_iovec(int type, const struct iovec __user *uvec,
- unsigned nr_segs, unsigned fast_segs, struct iovec **iovp,
- struct iov_iter *i, bool compat);
- int import_single_range(int type, void __user *buf, size_t len,
- struct iovec *iov, struct iov_iter *i);
- int iov_iter_for_each_range(struct iov_iter *i, size_t bytes,
- int (*f)(struct kvec *vec, void *context),
- void *context);
- #endif
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