iov_iter.c: convert iov_iter_get_pages_alloc() to iterate_all_kinds

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files 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);