UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity

unify the rest of iov_iter_get_pages()/iov_iter_get_pages_alloc() guts 

same as for pipes and xarrays; after that iov_iter_get_pages() becomes
a wrapper for __iov_iter_get_pages_alloc().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2022-06-17 13:54:15 -04:00
parent 68fe506f37
commit 451c0ba947
1 changed files with 33 additions and 65 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

98
lib/iov_iter.c
View File

@ -1448,64 +1448,10 @@ static struct page *first_bvec_segment(const struct iov_iter *i,
return page;
}
ssize_t iov_iter_get_pages(struct iov_iter *i,
struct page **pages, size_t maxsize, unsigned maxpages,
size_t *start)
{
int n, res;
if (maxsize > i->count)
maxsize = i->count;
if (!maxsize || !maxpages)
return 0;
if (maxsize > MAX_RW_COUNT)
maxsize = MAX_RW_COUNT;
BUG_ON(!pages);
if (likely(user_backed_iter(i))) {
unsigned int gup_flags = 0;
unsigned long addr;
if (iov_iter_rw(i) != WRITE)
gup_flags |= FOLL_WRITE;
if (i->nofault)
gup_flags |= FOLL_NOFAULT;
addr = first_iovec_segment(i, &maxsize);
*start = addr % PAGE_SIZE;
addr &= PAGE_MASK;
n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE);
if (n > maxpages)
n = maxpages;
res = get_user_pages_fast(addr, n, gup_flags, pages);
if (unlikely(res <= 0))
return res;
return min_t(size_t, maxsize, res * PAGE_SIZE - *start);
}
if (iov_iter_is_bvec(i)) {
struct page *page;
page = first_bvec_segment(i, &maxsize, start);
n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE);
if (n > maxpages)
n = maxpages;
for (int k = 0; k < n; k++)
get_page(*pages++ = page++);
return min_t(size_t, maxsize, n * PAGE_SIZE - *start);
}
if (iov_iter_is_pipe(i))
return pipe_get_pages(i, &pages, maxsize, maxpages, start);
if (iov_iter_is_xarray(i))
return iter_xarray_get_pages(i, &pages, maxsize, maxpages, start);
return -EFAULT;
}
EXPORT_SYMBOL(iov_iter_get_pages);
static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
struct page ***pages, size_t maxsize,
size_t *start)
unsigned int maxpages, size_t *start)
{
struct page **p;
int n, res;
if (maxsize > i->count)
@ -1528,33 +1474,55 @@ static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
*start = addr % PAGE_SIZE;
addr &= PAGE_MASK;
n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE);
*pages = p = get_pages_array(n);
if (!p)
return -ENOMEM;
res = get_user_pages_fast(addr, n, gup_flags, p);
if (n > maxpages)
n = maxpages;
if (!*pages) {
*pages = get_pages_array(n);
if (!*pages)
return -ENOMEM;
}
res = get_user_pages_fast(addr, n, gup_flags, *pages);
if (unlikely(res <= 0))
return res;
return min_t(size_t, maxsize, res * PAGE_SIZE - *start);
}
if (iov_iter_is_bvec(i)) {
struct page **p;
struct page *page;
page = first_bvec_segment(i, &maxsize, start);
n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE);
*pages = p = get_pages_array(n);
if (!p)
return -ENOMEM;
if (n > maxpages)
n = maxpages;
p = *pages;
if (!p) {
*pages = p = get_pages_array(n);
if (!p)
return -ENOMEM;
}
for (int k = 0; k < n; k++)
get_page(*p++ = page++);
return min_t(size_t, maxsize, n * PAGE_SIZE - *start);
}
if (iov_iter_is_pipe(i))
return pipe_get_pages(i, pages, maxsize, ~0U, start);
return pipe_get_pages(i, pages, maxsize, maxpages, start);
if (iov_iter_is_xarray(i))
return iter_xarray_get_pages(i, pages, maxsize, ~0U, start);
return iter_xarray_get_pages(i, pages, maxsize, maxpages, start);
return -EFAULT;
}
ssize_t iov_iter_get_pages(struct iov_iter *i,
struct page **pages, size_t maxsize, unsigned maxpages,
size_t *start)
{
if (!maxpages)
return 0;
BUG_ON(!pages);
return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages, start);
}
EXPORT_SYMBOL(iov_iter_get_pages);
ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
struct page ***pages, size_t maxsize,
size_t *start)
@ -1563,7 +1531,7 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
*pages = NULL;
len = __iov_iter_get_pages_alloc(i, pages, maxsize, start);
len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start);
if (len <= 0) {
kvfree(*pages);
*pages = NULL;