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iov_iter.c: convert iov_iter_get_pages() to iterate_all_kinds 

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2014-11-27 14:12:09 -05:00
parent e0f2dc4061
commit e5393fae3b
1 changed files with 28 additions and 50 deletions
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78
mm/iov_iter.c
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@ -428,34 +428,6 @@ void iov_iter_init(struct iov_iter *i, int direction,
}
EXPORT_SYMBOL(iov_iter_init);
static ssize_t get_pages_iovec(struct iov_iter *i,
struct page **pages, size_t maxsize, unsigned maxpages,
size_t *start)
{
size_t offset = i->iov_offset;
const struct iovec *iov = i->iov;
size_t len;
unsigned long addr;
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);
if (len > maxpages * PAGE_SIZE)
len = maxpages * PAGE_SIZE;
addr &= ~(PAGE_SIZE - 1);
n = (len + PAGE_SIZE - 1) / PAGE_SIZE;
res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, pages);
if (unlikely(res < 0))
return res;
return (res == n ? len : res * PAGE_SIZE) - *start;
}
static ssize_t get_pages_alloc_iovec(struct iov_iter *i,
struct page ***pages, size_t maxsize,
size_t *start)
@ -650,24 +622,6 @@ static size_t zero_bvec(size_t bytes, struct iov_iter *i)
return wanted - bytes;
}
static ssize_t get_pages_bvec(struct iov_iter *i,
struct page **pages, size_t maxsize, unsigned maxpages,
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;
/* can't be more than PAGE_SIZE */
*start = bvec->bv_offset + i->iov_offset;
get_page(*pages = bvec->bv_page);
return len;
}
static ssize_t get_pages_alloc_bvec(struct iov_iter *i,
struct page ***pages, size_t maxsize,
size_t *start)
@ -792,10 +746,34 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
struct page **pages, size_t maxsize, unsigned maxpages,
size_t *start)
{
if (i->type & ITER_BVEC)
return get_pages_bvec(i, pages, maxsize, maxpages, start);
else
return get_pages_iovec(i, pages, maxsize, maxpages, start);
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;
if (len > maxpages * PAGE_SIZE)
len = maxpages * PAGE_SIZE;
addr &= ~(PAGE_SIZE - 1);
n = DIV_ROUND_UP(len, PAGE_SIZE);
res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, pages);
if (unlikely(res < 0))
return res;
return (res == n ? len : res * PAGE_SIZE) - *start;
0;}),({
/* can't be more than PAGE_SIZE */
*start = v.bv_offset;
get_page(*pages = v.bv_page);
return v.bv_len;
})
)
return 0;
}
EXPORT_SYMBOL(iov_iter_get_pages);