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Date: Thu, 4 Dec 2014 20:23:07 +0000
From: Al Viro <viro@...IV.linux.org.uk>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
netdev@...r.kernel.org
Subject: [RFC][PATCH 03/13] iov_iter.c: convert iov_iter_npages() to iterate_all_kinds
From: Al Viro <viro@...iv.linux.org.uk>
Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
mm/iov_iter.c | 73 ++++++++++++++++-------------------------------------------
1 file changed, 19 insertions(+), 54 deletions(-)
diff --git a/mm/iov_iter.c b/mm/iov_iter.c
index e91bf0a..bc666e7 100644
--- a/mm/iov_iter.c
+++ b/mm/iov_iter.c
@@ -493,32 +493,6 @@ static ssize_t get_pages_alloc_iovec(struct iov_iter *i,
return (res == n ? len : res * PAGE_SIZE) - *start;
}
-static int iov_iter_npages_iovec(const struct iov_iter *i, int maxpages)
-{
- size_t offset = i->iov_offset;
- size_t size = i->count;
- const struct iovec *iov = i->iov;
- int npages = 0;
- int n;
-
- for (n = 0; size && n < i->nr_segs; n++, iov++) {
- unsigned long addr = (unsigned long)iov->iov_base + offset;
- size_t len = iov->iov_len - offset;
- offset = 0;
- if (unlikely(!len)) /* empty segment */
- continue;
- if (len > size)
- len = size;
- npages += (addr + len + PAGE_SIZE - 1) / PAGE_SIZE
- - addr / PAGE_SIZE;
- if (npages >= maxpages) /* don't bother going further */
- return maxpages;
- size -= len;
- offset = 0;
- }
- return min(npages, maxpages);
-}
-
static void memcpy_from_page(char *to, struct page *page, size_t offset, size_t len)
{
char *from = kmap_atomic(page);
@@ -715,30 +689,6 @@ static ssize_t get_pages_alloc_bvec(struct iov_iter *i,
return len;
}
-static int iov_iter_npages_bvec(const struct iov_iter *i, int maxpages)
-{
- size_t offset = i->iov_offset;
- size_t size = i->count;
- const struct bio_vec *bvec = i->bvec;
- int npages = 0;
- int n;
-
- for (n = 0; size && n < i->nr_segs; n++, bvec++) {
- size_t len = bvec->bv_len - offset;
- offset = 0;
- if (unlikely(!len)) /* empty segment */
- continue;
- if (len > size)
- len = size;
- npages++;
- if (npages >= maxpages) /* don't bother going further */
- return maxpages;
- size -= len;
- offset = 0;
- }
- return min(npages, maxpages);
-}
-
size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i)
{
@@ -862,9 +812,24 @@ EXPORT_SYMBOL(iov_iter_get_pages_alloc);
int iov_iter_npages(const struct iov_iter *i, int maxpages)
{
- if (i->type & ITER_BVEC)
- return iov_iter_npages_bvec(i, maxpages);
- else
- return iov_iter_npages_iovec(i, maxpages);
+ size_t size = i->count;
+ int npages = 0;
+
+ if (!size)
+ return 0;
+
+ iterate_all_kinds(i, size, v, ({
+ unsigned long p = (unsigned long)v.iov_base;
+ npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE)
+ - p / PAGE_SIZE;
+ if (npages >= maxpages)
+ return maxpages;
+ 0;}),({
+ npages++;
+ if (npages >= maxpages)
+ return maxpages;
+ })
+ )
+ return npages;
}
EXPORT_SYMBOL(iov_iter_npages);
--
2.1.3
--
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