From 1b17f1f2e56a091deb99a068a6f1e82b5bb76b09 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 27 Nov 2014 14:14:31 -0500 Subject: [PATCH] iov_iter.c: convert iov_iter_get_pages_alloc() to iterate_all_kinds Signed-off-by: Al Viro --- mm/iov_iter.c | 107 +++++++++++++++++++++----------------------------- 1 file changed, 45 insertions(+), 62 deletions(-) diff --git a/mm/iov_iter.c b/mm/iov_iter.c index 75e29ef59b0e..3214b9b493ae 100644 --- a/mm/iov_iter.c +++ b/mm/iov_iter.c @@ -428,43 +428,6 @@ void iov_iter_init(struct iov_iter *i, int direction, } EXPORT_SYMBOL(iov_iter_init); -static ssize_t get_pages_alloc_iovec(struct iov_iter *i, - struct page ***pages, size_t maxsize, - size_t *start) -{ - size_t offset = i->iov_offset; - const struct iovec *iov = i->iov; - size_t len; - unsigned long addr; - void *p; - int n; - int res; - - len = iov->iov_len - offset; - if (len > i->count) - len = i->count; - if (len > maxsize) - len = maxsize; - addr = (unsigned long)iov->iov_base + offset; - len += *start = addr & (PAGE_SIZE - 1); - addr &= ~(PAGE_SIZE - 1); - n = (len + PAGE_SIZE - 1) / PAGE_SIZE; - - p = kmalloc(n * sizeof(struct page *), GFP_KERNEL); - if (!p) - p = vmalloc(n * sizeof(struct page *)); - if (!p) - return -ENOMEM; - - res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p); - if (unlikely(res < 0)) { - kvfree(p); - return res; - } - *pages = p; - return (res == n ? len : res * PAGE_SIZE) - *start; -} - static void memcpy_from_page(char *to, struct page *page, size_t offset, size_t len) { char *from = kmap_atomic(page); @@ -622,27 +585,6 @@ static size_t zero_bvec(size_t bytes, struct iov_iter *i) return wanted - bytes; } -static ssize_t get_pages_alloc_bvec(struct iov_iter *i, - struct page ***pages, size_t maxsize, - size_t *start) -{ - const struct bio_vec *bvec = i->bvec; - size_t len = bvec->bv_len - i->iov_offset; - if (len > i->count) - len = i->count; - if (len > maxsize) - len = maxsize; - *start = bvec->bv_offset + i->iov_offset; - - *pages = kmalloc(sizeof(struct page *), GFP_KERNEL); - if (!*pages) - return -ENOMEM; - - get_page(**pages = bvec->bv_page); - - return len; -} - size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, struct iov_iter *i) { @@ -777,14 +719,55 @@ ssize_t iov_iter_get_pages(struct iov_iter *i, } EXPORT_SYMBOL(iov_iter_get_pages); +static struct page **get_pages_array(size_t n) +{ + struct page **p = kmalloc(n * sizeof(struct page *), GFP_KERNEL); + if (!p) + p = vmalloc(n * sizeof(struct page *)); + return p; +} + ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages, size_t maxsize, size_t *start) { - if (i->type & ITER_BVEC) - return get_pages_alloc_bvec(i, pages, maxsize, start); - else - return get_pages_alloc_iovec(i, pages, maxsize, start); + struct page **p; + + if (maxsize > i->count) + maxsize = i->count; + + if (!maxsize) + return 0; + + iterate_all_kinds(i, maxsize, v, ({ + unsigned long addr = (unsigned long)v.iov_base; + size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); + int n; + int res; + + addr &= ~(PAGE_SIZE - 1); + n = DIV_ROUND_UP(len, PAGE_SIZE); + p = get_pages_array(n); + if (!p) + return -ENOMEM; + res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p); + if (unlikely(res < 0)) { + kvfree(p); + return res; + } + *pages = p; + return (res == n ? len : res * PAGE_SIZE) - *start; + 0;}),({ + /* can't be more than PAGE_SIZE */ + *start = v.bv_offset; + *pages = p = get_pages_array(1); + if (!p) + return -ENOMEM; + get_page(*p = v.bv_page); + return v.bv_len; + }) + ) + return 0; } EXPORT_SYMBOL(iov_iter_get_pages_alloc); -- 2.20.1