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authorAl Viro <viro@zeniv.linux.org.uk>2022-06-17 20:54:15 +0300
committerAl Viro <viro@zeniv.linux.org.uk>2022-08-09 05:37:21 +0300
commit451c0ba9475ebdce36249c5c769efa5d580d1d83 (patch)
tree6b0c287ea66afd2ef05b76ad07038d1c9832a906 /lib
parent68fe506f3731ecf7881de9512cc5f4c14fd13f3a (diff)
downloadlinux-451c0ba9475ebdce36249c5c769efa5d580d1d83.tar.xz
unify the rest of iov_iter_get_pages()/iov_iter_get_pages_alloc() guts
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>
Diffstat (limited to 'lib')
-rw-r--r--lib/iov_iter.c86
1 files changed, 27 insertions, 59 deletions
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 6904a1cc36f2..8c6cdc1cf832 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1448,19 +1448,18 @@ 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)
{
int n, res;
if (maxsize > i->count)
maxsize = i->count;
- if (!maxsize || !maxpages)
+ if (!maxsize)
return 0;
if (maxsize > MAX_RW_COUNT)
maxsize = MAX_RW_COUNT;
- BUG_ON(!pages);
if (likely(user_backed_iter(i))) {
unsigned int gup_flags = 0;
@@ -1477,83 +1476,52 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE);
if (n > maxpages)
n = maxpages;
- 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 min_t(size_t, maxsize, res * PAGE_SIZE - *start);
}
if (iov_iter_is_bvec(i)) {
+ struct page **p;
struct page *page;
page = first_bvec_segment(i, &maxsize, start);
n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE);
if (n > maxpages)
n = maxpages;
+ p = *pages;
+ if (!p) {
+ *pages = p = get_pages_array(n);
+ if (!p)
+ return -ENOMEM;
+ }
for (int k = 0; k < n; k++)
- get_page(*pages++ = page++);
+ get_page(*p++ = page++);
return min_t(size_t, maxsize, n * PAGE_SIZE - *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;
- int n, res;
-
- if (maxsize > i->count)
- maxsize = i->count;
- if (!maxsize)
+ if (!maxpages)
return 0;
- if (maxsize > MAX_RW_COUNT)
- maxsize = MAX_RW_COUNT;
-
- 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, &maxsize);
- *start = addr % PAGE_SIZE;
- addr &= PAGE_MASK;
- n = DIV_ROUND_UP(maxsize + *start, 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;
- return min_t(size_t, maxsize, res * PAGE_SIZE - *start);
- }
- if (iov_iter_is_bvec(i)) {
- struct page *page;
+ BUG_ON(!pages);
- page = first_bvec_segment(i, &maxsize, start);
- n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE);
- *pages = p = get_pages_array(n);
- if (!p)
- return -ENOMEM;
- for (int k = 0; k < n; k++)
- get_page(*p++ = page++);
- return min_t(size_t, maxsize, n * PAGE_SIZE - *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,
@@ -1563,7 +1531,7 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
*pages = NULL;
- 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;