switch hugetlbfs to ->read_iter()
... and fix the case when the area we are asked to read crosses a hugepage boundary Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
Родитель
c12c49e702
Коммит
34d0640e26
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@ -34,6 +34,7 @@
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#include <linux/security.h>
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#include <linux/magic.h>
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#include <linux/migrate.h>
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#include <linux/uio.h>
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#include <asm/uaccess.h>
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@ -179,42 +180,33 @@ hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
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}
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#endif
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static int
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static size_t
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hugetlbfs_read_actor(struct page *page, unsigned long offset,
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char __user *buf, unsigned long count,
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unsigned long size)
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struct iov_iter *to, unsigned long size)
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{
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char *kaddr;
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unsigned long left, copied = 0;
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size_t copied = 0;
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int i, chunksize;
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if (size > count)
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size = count;
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/* Find which 4k chunk and offset with in that chunk */
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i = offset >> PAGE_CACHE_SHIFT;
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offset = offset & ~PAGE_CACHE_MASK;
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while (size) {
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size_t n;
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chunksize = PAGE_CACHE_SIZE;
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if (offset)
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chunksize -= offset;
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if (chunksize > size)
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chunksize = size;
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kaddr = kmap(&page[i]);
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left = __copy_to_user(buf, kaddr + offset, chunksize);
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kunmap(&page[i]);
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if (left) {
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copied += (chunksize - left);
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break;
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}
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n = copy_page_to_iter(&page[i], offset, chunksize, to);
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copied += n;
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if (n != chunksize)
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return copied;
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offset = 0;
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size -= chunksize;
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buf += chunksize;
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copied += chunksize;
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i++;
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}
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return copied ? copied : -EFAULT;
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return copied;
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}
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/*
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@ -222,39 +214,34 @@ hugetlbfs_read_actor(struct page *page, unsigned long offset,
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* data. Its *very* similar to do_generic_mapping_read(), we can't use that
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* since it has PAGE_CACHE_SIZE assumptions.
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*/
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static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
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size_t len, loff_t *ppos)
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static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
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{
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struct hstate *h = hstate_file(filp);
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struct address_space *mapping = filp->f_mapping;
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struct file *file = iocb->ki_filp;
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struct hstate *h = hstate_file(file);
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struct address_space *mapping = file->f_mapping;
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struct inode *inode = mapping->host;
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unsigned long index = *ppos >> huge_page_shift(h);
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unsigned long offset = *ppos & ~huge_page_mask(h);
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unsigned long index = iocb->ki_pos >> huge_page_shift(h);
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unsigned long offset = iocb->ki_pos & ~huge_page_mask(h);
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unsigned long end_index;
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loff_t isize;
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ssize_t retval = 0;
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/* validate length */
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if (len == 0)
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goto out;
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for (;;) {
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while (iov_iter_count(to)) {
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struct page *page;
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unsigned long nr, ret;
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int ra;
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size_t nr, copied;
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/* nr is the maximum number of bytes to copy from this page */
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nr = huge_page_size(h);
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isize = i_size_read(inode);
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if (!isize)
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goto out;
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break;
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end_index = (isize - 1) >> huge_page_shift(h);
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if (index >= end_index) {
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if (index > end_index)
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goto out;
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if (index > end_index)
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break;
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if (index == end_index) {
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nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
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if (nr <= offset)
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goto out;
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break;
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}
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nr = nr - offset;
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@ -265,39 +252,27 @@ static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
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* We have a HOLE, zero out the user-buffer for the
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* length of the hole or request.
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*/
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ret = len < nr ? len : nr;
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if (clear_user(buf, ret))
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ra = -EFAULT;
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else
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ra = 0;
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copied = iov_iter_zero(nr, to);
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} else {
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unlock_page(page);
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/*
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* We have the page, copy it to user space buffer.
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*/
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ra = hugetlbfs_read_actor(page, offset, buf, len, nr);
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ret = ra;
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copied = hugetlbfs_read_actor(page, offset, to, nr);
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page_cache_release(page);
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}
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if (ra < 0) {
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if (retval == 0)
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retval = ra;
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goto out;
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offset += copied;
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retval += copied;
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if (copied != nr && iov_iter_count(to)) {
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if (!retval)
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retval = -EFAULT;
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break;
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}
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offset += ret;
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retval += ret;
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len -= ret;
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index += offset >> huge_page_shift(h);
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offset &= ~huge_page_mask(h);
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/* short read or no more work */
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if ((ret != nr) || (len == 0))
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break;
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}
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out:
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*ppos = ((loff_t)index << huge_page_shift(h)) + offset;
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iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset;
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return retval;
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}
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@ -721,7 +696,8 @@ static void init_once(void *foo)
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}
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const struct file_operations hugetlbfs_file_operations = {
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.read = hugetlbfs_read,
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.read = new_sync_read,
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.read_iter = hugetlbfs_read_iter,
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.mmap = hugetlbfs_file_mmap,
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.fsync = noop_fsync,
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.get_unmapped_area = hugetlb_get_unmapped_area,
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