iov_iter.c: convert iov_iter_get_pages_alloc() to iterate_all_kinds
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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parent
e5393fae3b
commit
1b17f1f2e5
107
mm/iov_iter.c
107
mm/iov_iter.c
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@ -428,43 +428,6 @@ void iov_iter_init(struct iov_iter *i, int direction,
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}
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EXPORT_SYMBOL(iov_iter_init);
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static ssize_t get_pages_alloc_iovec(struct iov_iter *i,
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struct page ***pages, size_t maxsize,
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size_t *start)
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{
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size_t offset = i->iov_offset;
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const struct iovec *iov = i->iov;
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size_t len;
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unsigned long addr;
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void *p;
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int n;
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int res;
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len = iov->iov_len - offset;
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if (len > i->count)
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len = i->count;
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if (len > maxsize)
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len = maxsize;
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addr = (unsigned long)iov->iov_base + offset;
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len += *start = addr & (PAGE_SIZE - 1);
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addr &= ~(PAGE_SIZE - 1);
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n = (len + PAGE_SIZE - 1) / PAGE_SIZE;
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p = kmalloc(n * sizeof(struct page *), GFP_KERNEL);
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if (!p)
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p = vmalloc(n * sizeof(struct page *));
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if (!p)
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return -ENOMEM;
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res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p);
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if (unlikely(res < 0)) {
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kvfree(p);
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return res;
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}
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*pages = p;
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return (res == n ? len : res * PAGE_SIZE) - *start;
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}
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static void memcpy_from_page(char *to, struct page *page, size_t offset, size_t len)
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{
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char *from = kmap_atomic(page);
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@ -622,27 +585,6 @@ static size_t zero_bvec(size_t bytes, struct iov_iter *i)
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return wanted - bytes;
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}
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static ssize_t get_pages_alloc_bvec(struct iov_iter *i,
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struct page ***pages, size_t maxsize,
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size_t *start)
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{
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const struct bio_vec *bvec = i->bvec;
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size_t len = bvec->bv_len - i->iov_offset;
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if (len > i->count)
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len = i->count;
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if (len > maxsize)
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len = maxsize;
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*start = bvec->bv_offset + i->iov_offset;
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*pages = kmalloc(sizeof(struct page *), GFP_KERNEL);
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if (!*pages)
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return -ENOMEM;
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get_page(**pages = bvec->bv_page);
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return len;
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}
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size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
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struct iov_iter *i)
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{
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@ -777,14 +719,55 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
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}
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EXPORT_SYMBOL(iov_iter_get_pages);
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static struct page **get_pages_array(size_t n)
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{
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struct page **p = kmalloc(n * sizeof(struct page *), GFP_KERNEL);
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if (!p)
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p = vmalloc(n * sizeof(struct page *));
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return p;
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}
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ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
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struct page ***pages, size_t maxsize,
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size_t *start)
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{
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if (i->type & ITER_BVEC)
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return get_pages_alloc_bvec(i, pages, maxsize, start);
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else
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return get_pages_alloc_iovec(i, pages, maxsize, start);
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struct page **p;
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if (maxsize > i->count)
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maxsize = i->count;
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if (!maxsize)
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return 0;
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iterate_all_kinds(i, maxsize, v, ({
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unsigned long addr = (unsigned long)v.iov_base;
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size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));
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int n;
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int res;
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addr &= ~(PAGE_SIZE - 1);
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n = DIV_ROUND_UP(len, PAGE_SIZE);
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p = get_pages_array(n);
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if (!p)
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return -ENOMEM;
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res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p);
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if (unlikely(res < 0)) {
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kvfree(p);
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return res;
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}
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*pages = p;
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return (res == n ? len : res * PAGE_SIZE) - *start;
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0;}),({
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/* can't be more than PAGE_SIZE */
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*start = v.bv_offset;
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*pages = p = get_pages_array(1);
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if (!p)
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return -ENOMEM;
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get_page(*p = v.bv_page);
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return v.bv_len;
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})
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)
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return 0;
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}
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EXPORT_SYMBOL(iov_iter_get_pages_alloc);
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