X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=lib%2Fiov_iter.c;h=d0c3e939ee6010a9a7e355ee242b3fce4a40a03b;hb=refs%2Fheads%2Faccepted%2Ftizen_8.0_unified;hp=755c10c5138cdb51d5da166ee2900565dfdfde38;hpb=0950fcbf992f578575f5387decb06f6496aab594;p=platform%2Fkernel%2Flinux-rpi.git diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 755c10c..d0c3e93 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -191,7 +191,7 @@ static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t b buf = iov->iov_base + skip; copy = min(bytes, iov->iov_len - skip); - if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) { + if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_writeable(buf, copy)) { kaddr = kmap_atomic(page); from = kaddr + offset; @@ -275,7 +275,7 @@ static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t buf = iov->iov_base + skip; copy = min(bytes, iov->iov_len - skip); - if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) { + if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_readable(buf, copy)) { kaddr = kmap_atomic(page); to = kaddr + offset; @@ -416,6 +416,7 @@ static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t by return 0; buf->ops = &page_cache_pipe_buf_ops; + buf->flags = 0; get_page(page); buf->page = page; buf->offset = offset; @@ -430,35 +431,81 @@ out: } /* + * fault_in_iov_iter_readable - fault in iov iterator for reading + * @i: iterator + * @size: maximum length + * * Fault in one or more iovecs of the given iov_iter, to a maximum length of - * bytes. For each iovec, fault in each page that constitutes the iovec. + * @size. For each iovec, fault in each page that constitutes the iovec. + * + * Returns the number of bytes not faulted in (like copy_to_user() and + * copy_from_user()). * - * Return 0 on success, or non-zero if the memory could not be accessed (i.e. - * because it is an invalid address). + * Always returns 0 for non-userspace iterators. */ -int iov_iter_fault_in_readable(const struct iov_iter *i, size_t bytes) +size_t fault_in_iov_iter_readable(const struct iov_iter *i, size_t size) { if (iter_is_iovec(i)) { + size_t count = min(size, iov_iter_count(i)); const struct iovec *p; size_t skip; - if (bytes > i->count) - bytes = i->count; - for (p = i->iov, skip = i->iov_offset; bytes; p++, skip = 0) { - size_t len = min(bytes, p->iov_len - skip); - int err; + size -= count; + for (p = i->iov, skip = i->iov_offset; count; p++, skip = 0) { + size_t len = min(count, p->iov_len - skip); + size_t ret; if (unlikely(!len)) continue; - err = fault_in_pages_readable(p->iov_base + skip, len); - if (unlikely(err)) - return err; - bytes -= len; + ret = fault_in_readable(p->iov_base + skip, len); + count -= len - ret; + if (ret) + break; } + return count + size; } return 0; } -EXPORT_SYMBOL(iov_iter_fault_in_readable); +EXPORT_SYMBOL(fault_in_iov_iter_readable); + +/* + * fault_in_iov_iter_writeable - fault in iov iterator for writing + * @i: iterator + * @size: maximum length + * + * Faults in the iterator using get_user_pages(), i.e., without triggering + * hardware page faults. This is primarily useful when we already know that + * some or all of the pages in @i aren't in memory. + * + * Returns the number of bytes not faulted in, like copy_to_user() and + * copy_from_user(). + * + * Always returns 0 for non-user-space iterators. + */ +size_t fault_in_iov_iter_writeable(const struct iov_iter *i, size_t size) +{ + if (iter_is_iovec(i)) { + size_t count = min(size, iov_iter_count(i)); + const struct iovec *p; + size_t skip; + + size -= count; + for (p = i->iov, skip = i->iov_offset; count; p++, skip = 0) { + size_t len = min(count, p->iov_len - skip); + size_t ret; + + if (unlikely(!len)) + continue; + ret = fault_in_safe_writeable(p->iov_base + skip, len); + count -= len - ret; + if (ret) + break; + } + return count + size; + } + return 0; +} +EXPORT_SYMBOL(fault_in_iov_iter_writeable); void iov_iter_init(struct iov_iter *i, unsigned int direction, const struct iovec *iov, unsigned long nr_segs, @@ -467,6 +514,7 @@ void iov_iter_init(struct iov_iter *i, unsigned int direction, WARN_ON(direction & ~(READ | WRITE)); *i = (struct iov_iter) { .iter_type = ITER_IOVEC, + .nofault = false, .data_source = direction, .iov = iov, .nr_segs = nr_segs, @@ -532,6 +580,7 @@ static size_t push_pipe(struct iov_iter *i, size_t size, break; buf->ops = &default_pipe_buf_ops; + buf->flags = 0; buf->page = page; buf->offset = 0; buf->len = min_t(ssize_t, left, PAGE_SIZE); @@ -642,6 +691,7 @@ static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, struct pipe_inode_info *pipe = i->pipe; unsigned int p_mask = pipe->ring_size - 1; unsigned int i_head; + unsigned int valid = pipe->head; size_t n, off, xfer = 0; if (!sanity(i)) @@ -655,11 +705,17 @@ static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, rem = copy_mc_to_kernel(p + off, addr + xfer, chunk); chunk -= rem; kunmap_local(p); - i->head = i_head; - i->iov_offset = off + chunk; - xfer += chunk; - if (rem) + if (chunk) { + i->head = i_head; + i->iov_offset = off + chunk; + xfer += chunk; + valid = i_head + 1; + } + if (rem) { + pipe->bufs[i_head & p_mask].len -= rem; + pipe_discard_from(pipe, valid); break; + } n -= chunk; off = 0; i_head++; @@ -1387,7 +1443,7 @@ static ssize_t iter_xarray_get_pages(struct iov_iter *i, { unsigned nr, offset; pgoff_t index, count; - size_t size = maxsize, actual; + size_t size = maxsize; loff_t pos; if (!size || !maxpages) @@ -1414,13 +1470,7 @@ static ssize_t iter_xarray_get_pages(struct iov_iter *i, if (nr == 0) return 0; - actual = PAGE_SIZE * nr; - actual -= offset; - if (nr == count && size > 0) { - unsigned last_offset = (nr > 1) ? 0 : offset; - actual -= PAGE_SIZE - (last_offset + size); - } - return actual; + return min_t(size_t, nr * PAGE_SIZE - offset, maxsize); } /* must be done on non-empty ITER_IOVEC one */ @@ -1481,14 +1531,18 @@ ssize_t iov_iter_get_pages(struct iov_iter *i, return 0; if (likely(iter_is_iovec(i))) { + unsigned int gup_flags = 0; unsigned long addr; + if (iov_iter_rw(i) != WRITE) + gup_flags |= FOLL_WRITE; + if (i->nofault) + gup_flags |= FOLL_NOFAULT; + addr = first_iovec_segment(i, &len, start, maxsize, maxpages); n = DIV_ROUND_UP(len, PAGE_SIZE); - res = get_user_pages_fast(addr, n, - iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, - pages); - if (unlikely(res < 0)) + res = get_user_pages_fast(addr, n, gup_flags, pages); + if (unlikely(res <= 0)) return res; return (res == n ? len : res * PAGE_SIZE) - *start; } @@ -1551,7 +1605,7 @@ static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, struct page **p; unsigned nr, offset; pgoff_t index, count; - size_t size = maxsize, actual; + size_t size = maxsize; loff_t pos; if (!size) @@ -1580,13 +1634,7 @@ static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, if (nr == 0) return 0; - actual = PAGE_SIZE * nr; - actual -= offset; - if (nr == count && size > 0) { - unsigned last_offset = (nr > 1) ? 0 : offset; - actual -= PAGE_SIZE - (last_offset + size); - } - return actual; + return min_t(size_t, nr * PAGE_SIZE - offset, maxsize); } ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, @@ -1603,17 +1651,23 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, return 0; if (likely(iter_is_iovec(i))) { + unsigned int gup_flags = 0; unsigned long addr; + if (iov_iter_rw(i) != WRITE) + gup_flags |= FOLL_WRITE; + if (i->nofault) + gup_flags |= FOLL_NOFAULT; + addr = first_iovec_segment(i, &len, start, maxsize, ~0U); n = DIV_ROUND_UP(len, PAGE_SIZE); p = get_pages_array(n); if (!p) return -ENOMEM; - res = get_user_pages_fast(addr, n, - iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, p); - if (unlikely(res < 0)) { + res = get_user_pages_fast(addr, n, gup_flags, p); + if (unlikely(res <= 0)) { kvfree(p); + *pages = NULL; return res; } *pages = p;