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iov_iter.c: convert iov_iter_get_pages_alloc() to iterate_all_kinds

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2014-11-27 14:14:31 -05:00
parent e5393fae3b
commit 1b17f1f2e5
1 changed files with 45 additions and 62 deletions
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107
mm/iov_iter.c
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@ -428,43 +428,6 @@ void iov_iter_init(struct iov_iter *i, int direction,
} }
EXPORT_SYMBOL(iov_iter_init); 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) static void memcpy_from_page(char *to, struct page *page, size_t offset, size_t len)
{ {
char *from = kmap_atomic(page); char *from = kmap_atomic(page);
@ -622,27 +585,6 @@ static size_t zero_bvec(size_t bytes, struct iov_iter *i)
return wanted - bytes; 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, size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i) struct iov_iter *i)
{ {
@ -777,14 +719,55 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
} }
EXPORT_SYMBOL(iov_iter_get_pages); 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, ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
struct page ***pages, size_t maxsize, struct page ***pages, size_t maxsize,
size_t *start) size_t *start)
{ {
if (i->type & ITER_BVEC) struct page **p;
return get_pages_alloc_bvec(i, pages, maxsize, start);
else if (maxsize > i->count)
return get_pages_alloc_iovec(i, pages, maxsize, start); 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); EXPORT_SYMBOL(iov_iter_get_pages_alloc);