@@ -1372,20 +1372,19 @@ static struct page *first_bvec_segment(const struct iov_iter *i,
return page;
}
-ssize_t iov_iter_get_pages(struct iov_iter *i,
- struct page **pages, size_t maxsize, unsigned maxpages,
- size_t *start)
+static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
+ struct page ***pages, size_t maxsize,
+ unsigned int maxpages, size_t *start)
{
size_t len;
int n, res;
if (maxsize > i->count)
maxsize = i->count;
- if (!maxsize || maxpages)
+ if (!maxsize)
return 0;
if (maxsize > LONG_MAX)
maxsize = LONG_MAX;
- BUG_ON(!pages);
if (likely(user_backed_iter(i))) {
unsigned int gup_flags = 0;
@@ -1398,78 +1397,53 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
addr = first_iovec_segment(i, &len, start, maxsize, maxpages);
n = DIV_ROUND_UP(len, PAGE_SIZE);
- res = get_user_pages_fast(addr, n, gup_flags, pages);
+ if (*pages) {
+ *pages = get_pages_array(n);
+ if (!*pages)
+ return -ENOMEM;
+ }
+ res = get_user_pages_fast(addr, n, gup_flags, *pages);
if (unlikely(res <= 0))
return res;
- return (res == n ? len : res * PAGE_SIZE) - *start;
+ if (res < n)
+ len = res * PAGE_SIZE;
+ return len - *start;
}
if (iov_iter_is_bvec(i)) {
+ struct page **p;
struct page *page;
page = first_bvec_segment(i, &len, start, maxsize, maxpages);
n = DIV_ROUND_UP(len, PAGE_SIZE);
- while (n--)
- get_page(*pages++ = page++);
+ p = *pages;
+ if (!p) {
+ *pages = p = get_pages_array(n);
+ if (!p)
+ return -ENOMEM;
+ }
+ for (int k = 0; k < n; k++)
+ get_page(*p++ = page++);
return len - *start;
}
if (iov_iter_is_pipe(i))
- return pipe_get_pages(i, &pages, maxsize, maxpages, start);
+ return pipe_get_pages(i, pages, maxsize, maxpages, start);
if (iov_iter_is_xarray(i))
- return iter_xarray_get_pages(i, &pages, maxsize, maxpages, start);
+ return iter_xarray_get_pages(i, pages, maxsize, maxpages,
+ start);
return -EFAULT;
}
-EXPORT_SYMBOL(iov_iter_get_pages);
-static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
- struct page ***pages, size_t maxsize,
+ssize_t iov_iter_get_pages(struct iov_iter *i,
+ struct page **pages, size_t maxsize, unsigned maxpages,
size_t *start)
{
- struct page **p;
- size_t len;
- int n, res;
-
- if (maxsize > LONG_MAX)
- maxsize = LONG_MAX;
-
- if (likely(user_backed_iter(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);
- *pages = p = get_pages_array(n);
- if (!p)
- return -ENOMEM;
- res = get_user_pages_fast(addr, n, gup_flags, p);
- if (unlikely(res <= 0))
- return res;
- if (res < n)
- len = res * PAGE_SIZE;
- return len - *start;
- }
- if (iov_iter_is_bvec(i)) {
- struct page *page;
+ if (!maxpages)
+ return 0;
+ BUG_ON(!pages);
- page = first_bvec_segment(i, &len, start, maxsize, ~0U);
- n = DIV_ROUND_UP(len, PAGE_SIZE);
- *pages = p = get_pages_array(n);
- if (!p)
- return -ENOMEM;
- while (n--)
- get_page(*p++ = page++);
- return len - *start;
- }
- if (iov_iter_is_pipe(i))
- return pipe_get_pages(i, pages, maxsize, ~0U, start);
- if (iov_iter_is_xarray(i))
- return iter_xarray_get_pages(i, pages, maxsize, ~0U, start);
- return -EFAULT;
+ return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages, start);
}
+EXPORT_SYMBOL(iov_iter_get_pages);
ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
struct page ***pages, size_t maxsize,
@@ -1479,12 +1453,7 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
*pages = NULL;
- if (maxsize > i->count)
- maxsize = i->count;
- if (!maxsize)
- return 0;
-
- len = __iov_iter_get_pages_alloc(i, pages, maxsize, start);
+ len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start);
if (len <= 0) {
kvfree(*pages);
*pages = NULL;
same as for pipes and xarrays; after that iov_iter_get_pages() becomes a wrapper for __iov_iter_get_pages_alloc(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> --- lib/iov_iter.c | 97 +++++++++++++++++--------------------------------- 1 file changed, 33 insertions(+), 64 deletions(-)