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iov_iter.c: convert iov_iter_npages() to iterate_all_kinds 

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2014-11-27 14:09:46 -05:00
parent 7ce2a91e51
commit e0f2dc4061
1 changed files with 19 additions and 54 deletions
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73
mm/iov_iter.c
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@ -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);