Commit 34d0640e authored by Al Viro's avatar Al Viro
Browse files

switch hugetlbfs to ->read_iter()



... and fix the case when the area we are asked to read crosses
a hugepage boundary
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent c12c49e7
......@@ -34,6 +34,7 @@
#include <linux/security.h>
#include <linux/magic.h>
#include <linux/migrate.h>
#include <linux/uio.h>
#include <asm/uaccess.h>
......@@ -179,42 +180,33 @@ hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
}
#endif
static int
static size_t
hugetlbfs_read_actor(struct page *page, unsigned long offset,
char __user *buf, unsigned long count,
unsigned long size)
struct iov_iter *to, unsigned long size)
{
char *kaddr;
unsigned long left, copied = 0;
size_t copied = 0;
int i, chunksize;
if (size > count)
size = count;
/* Find which 4k chunk and offset with in that chunk */
i = offset >> PAGE_CACHE_SHIFT;
offset = offset & ~PAGE_CACHE_MASK;
while (size) {
size_t n;
chunksize = PAGE_CACHE_SIZE;
if (offset)
chunksize -= offset;
if (chunksize > size)
chunksize = size;
kaddr = kmap(&page[i]);
left = __copy_to_user(buf, kaddr + offset, chunksize);
kunmap(&page[i]);
if (left) {
copied += (chunksize - left);
break;
}
n = copy_page_to_iter(&page[i], offset, chunksize, to);
copied += n;
if (n != chunksize)
return copied;
offset = 0;
size -= chunksize;
buf += chunksize;
copied += chunksize;
i++;
}
return copied ? copied : -EFAULT;
return copied;
}
/*
......@@ -222,39 +214,34 @@ hugetlbfs_read_actor(struct page *page, unsigned long offset,
* data. Its *very* similar to do_generic_mapping_read(), we can't use that
* since it has PAGE_CACHE_SIZE assumptions.
*/
static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
size_t len, loff_t *ppos)
static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct hstate *h = hstate_file(filp);
struct address_space *mapping = filp->f_mapping;
struct file *file = iocb->ki_filp;
struct hstate *h = hstate_file(file);
struct address_space *mapping = file->f_mapping;
struct inode *inode = mapping->host;
unsigned long index = *ppos >> huge_page_shift(h);
unsigned long offset = *ppos & ~huge_page_mask(h);
unsigned long index = iocb->ki_pos >> huge_page_shift(h);
unsigned long offset = iocb->ki_pos & ~huge_page_mask(h);
unsigned long end_index;
loff_t isize;
ssize_t retval = 0;
/* validate length */
if (len == 0)
goto out;
for (;;) {
while (iov_iter_count(to)) {
struct page *page;
unsigned long nr, ret;
int ra;
size_t nr, copied;
/* nr is the maximum number of bytes to copy from this page */
nr = huge_page_size(h);
isize = i_size_read(inode);
if (!isize)
goto out;
break;
end_index = (isize - 1) >> huge_page_shift(h);
if (index >= end_index) {
if (index > end_index)
goto out;
if (index > end_index)
break;
if (index == end_index) {
nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
if (nr <= offset)
goto out;
break;
}
nr = nr - offset;
......@@ -265,39 +252,27 @@ static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
* We have a HOLE, zero out the user-buffer for the
* length of the hole or request.
*/
ret = len < nr ? len : nr;
if (clear_user(buf, ret))
ra = -EFAULT;
else
ra = 0;
copied = iov_iter_zero(nr, to);
} else {
unlock_page(page);
/*
* We have the page, copy it to user space buffer.
*/
ra = hugetlbfs_read_actor(page, offset, buf, len, nr);
ret = ra;
copied = hugetlbfs_read_actor(page, offset, to, nr);
page_cache_release(page);
}
if (ra < 0) {
if (retval == 0)
retval = ra;
goto out;
offset += copied;
retval += copied;
if (copied != nr && iov_iter_count(to)) {
if (!retval)
retval = -EFAULT;
break;
}
offset += ret;
retval += ret;
len -= ret;
index += offset >> huge_page_shift(h);
offset &= ~huge_page_mask(h);
/* short read or no more work */
if ((ret != nr) || (len == 0))
break;
}
out:
*ppos = ((loff_t)index << huge_page_shift(h)) + offset;
iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset;
return retval;
}
......@@ -721,7 +696,8 @@ static void init_once(void *foo)
}
const struct file_operations hugetlbfs_file_operations = {
.read = hugetlbfs_read,
.read = new_sync_read,
.read_iter = hugetlbfs_read_iter,
.mmap = hugetlbfs_file_mmap,
.fsync = noop_fsync,
.get_unmapped_area = hugetlb_get_unmapped_area,
......
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