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Date: Thu, 4 Dec 2014 20:23:09 +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 05/13] iov_iter.c: convert iov_iter_get_pages_alloc() 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 | 107 ++++++++++++++++++++++++----------------------------------
1 file changed, 45 insertions(+), 62 deletions(-)
diff --git a/mm/iov_iter.c b/mm/iov_iter.c
index 75e29ef..3214b9b 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);
--
2.1.3
--
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