![Carsten Otte](/assets/img/avatar_default.png)
- generic_file* file operations do no longer have a xip/non-xip split - filemap_xip.c implements a new set of fops that require get_xip_page aop to work proper. all new fops are exported GPL-only (don't like to see whatever code use those except GPL modules) - __xip_unmap now uses page_check_address, which is no longer static in rmap.c, and defined in linux/rmap.h - mm/filemap.h is now much more clean, plainly having just Linus' inline funcs moved here from filemap.c - fix includes in filemap_xip to make it build cleanly on i386 Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
582 lines
14 KiB
C
582 lines
14 KiB
C
/*
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* linux/mm/filemap_xip.c
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*
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* Copyright (C) 2005 IBM Corporation
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* Author: Carsten Otte <cotte@de.ibm.com>
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*
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* derived from linux/mm/filemap.c - Copyright (C) Linus Torvalds
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*
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*/
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#include <linux/fs.h>
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#include <linux/pagemap.h>
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#include <linux/module.h>
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#include <linux/uio.h>
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#include <linux/rmap.h>
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#include <asm/tlbflush.h>
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#include "filemap.h"
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/*
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* This is a file read routine for execute in place files, and uses
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* the mapping->a_ops->get_xip_page() function for the actual low-level
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* stuff.
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*
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* Note the struct file* is not used at all. It may be NULL.
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*/
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static void
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do_xip_mapping_read(struct address_space *mapping,
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struct file_ra_state *_ra,
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struct file *filp,
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loff_t *ppos,
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read_descriptor_t *desc,
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read_actor_t actor)
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{
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struct inode *inode = mapping->host;
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unsigned long index, end_index, offset;
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loff_t isize;
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BUG_ON(!mapping->a_ops->get_xip_page);
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index = *ppos >> PAGE_CACHE_SHIFT;
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offset = *ppos & ~PAGE_CACHE_MASK;
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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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end_index = (isize - 1) >> PAGE_CACHE_SHIFT;
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for (;;) {
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struct page *page;
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unsigned long nr, ret;
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/* nr is the maximum number of bytes to copy from this page */
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nr = PAGE_CACHE_SIZE;
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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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nr = ((isize - 1) & ~PAGE_CACHE_MASK) + 1;
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if (nr <= offset) {
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goto out;
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}
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}
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nr = nr - offset;
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page = mapping->a_ops->get_xip_page(mapping,
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index*(PAGE_SIZE/512), 0);
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if (!page)
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goto no_xip_page;
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if (unlikely(IS_ERR(page))) {
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if (PTR_ERR(page) == -ENODATA) {
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/* sparse */
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page = virt_to_page(empty_zero_page);
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} else {
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desc->error = PTR_ERR(page);
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goto out;
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}
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} else
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BUG_ON(!PageUptodate(page));
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/* If users can be writing to this page using arbitrary
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* virtual addresses, take care about potential aliasing
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* before reading the page on the kernel side.
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*/
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if (mapping_writably_mapped(mapping))
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flush_dcache_page(page);
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/*
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* Ok, we have the page, and it's up-to-date, so
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* now we can copy it to user space...
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*
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* The actor routine returns how many bytes were actually used..
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* NOTE! This may not be the same as how much of a user buffer
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* we filled up (we may be padding etc), so we can only update
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* "pos" here (the actor routine has to update the user buffer
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* pointers and the remaining count).
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*/
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ret = actor(desc, page, offset, nr);
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offset += ret;
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index += offset >> PAGE_CACHE_SHIFT;
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offset &= ~PAGE_CACHE_MASK;
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if (ret == nr && desc->count)
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continue;
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goto out;
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no_xip_page:
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/* Did not get the page. Report it */
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desc->error = -EIO;
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goto out;
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}
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out:
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*ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset;
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if (filp)
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file_accessed(filp);
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}
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/*
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* This is the "read()" routine for all filesystems
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* that uses the get_xip_page address space operation.
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*/
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static ssize_t
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__xip_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
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unsigned long nr_segs, loff_t *ppos)
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{
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struct file *filp = iocb->ki_filp;
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ssize_t retval;
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unsigned long seg;
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size_t count;
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count = 0;
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for (seg = 0; seg < nr_segs; seg++) {
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const struct iovec *iv = &iov[seg];
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/*
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* If any segment has a negative length, or the cumulative
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* length ever wraps negative then return -EINVAL.
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*/
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count += iv->iov_len;
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if (unlikely((ssize_t)(count|iv->iov_len) < 0))
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return -EINVAL;
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if (access_ok(VERIFY_WRITE, iv->iov_base, iv->iov_len))
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continue;
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if (seg == 0)
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return -EFAULT;
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nr_segs = seg;
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count -= iv->iov_len; /* This segment is no good */
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break;
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}
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retval = 0;
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if (count) {
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for (seg = 0; seg < nr_segs; seg++) {
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read_descriptor_t desc;
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desc.written = 0;
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desc.arg.buf = iov[seg].iov_base;
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desc.count = iov[seg].iov_len;
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if (desc.count == 0)
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continue;
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desc.error = 0;
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do_xip_mapping_read(filp->f_mapping, &filp->f_ra, filp,
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ppos, &desc, file_read_actor);
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retval += desc.written;
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if (!retval) {
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retval = desc.error;
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break;
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}
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}
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}
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return retval;
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}
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ssize_t
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xip_file_aio_read(struct kiocb *iocb, char __user *buf, size_t count,
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loff_t pos)
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{
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struct iovec local_iov = { .iov_base = buf, .iov_len = count };
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BUG_ON(iocb->ki_pos != pos);
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return __xip_file_aio_read(iocb, &local_iov, 1, &iocb->ki_pos);
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}
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EXPORT_SYMBOL_GPL(xip_file_aio_read);
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ssize_t
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xip_file_readv(struct file *filp, const struct iovec *iov,
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unsigned long nr_segs, loff_t *ppos)
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{
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struct kiocb kiocb;
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init_sync_kiocb(&kiocb, filp);
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return __xip_file_aio_read(&kiocb, iov, nr_segs, ppos);
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}
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EXPORT_SYMBOL_GPL(xip_file_readv);
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ssize_t
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xip_file_sendfile(struct file *in_file, loff_t *ppos,
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size_t count, read_actor_t actor, void *target)
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{
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read_descriptor_t desc;
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if (!count)
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return 0;
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desc.written = 0;
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desc.count = count;
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desc.arg.data = target;
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desc.error = 0;
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do_xip_mapping_read(in_file->f_mapping, &in_file->f_ra, in_file,
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ppos, &desc, actor);
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if (desc.written)
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return desc.written;
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return desc.error;
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}
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EXPORT_SYMBOL_GPL(xip_file_sendfile);
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/*
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* __xip_unmap is invoked from xip_unmap and
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* xip_write
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*
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* This function walks all vmas of the address_space and unmaps the
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* empty_zero_page when found at pgoff. Should it go in rmap.c?
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*/
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static void
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__xip_unmap (struct address_space * mapping,
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unsigned long pgoff)
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{
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struct vm_area_struct *vma;
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struct mm_struct *mm;
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struct prio_tree_iter iter;
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unsigned long address;
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pte_t *pte;
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pte_t pteval;
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spin_lock(&mapping->i_mmap_lock);
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vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
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mm = vma->vm_mm;
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address = vma->vm_start +
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((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
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BUG_ON(address < vma->vm_start || address >= vma->vm_end);
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/*
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* We need the page_table_lock to protect us from page faults,
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* munmap, fork, etc...
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*/
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pte = page_check_address(virt_to_page(empty_zero_page), mm,
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address);
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if (!IS_ERR(pte)) {
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/* Nuke the page table entry. */
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flush_cache_page(vma, address, pte_pfn(pte));
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pteval = ptep_clear_flush(vma, address, pte);
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BUG_ON(pte_dirty(pteval));
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pte_unmap(pte);
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spin_unlock(&mm->page_table_lock);
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}
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}
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spin_unlock(&mapping->i_mmap_lock);
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}
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/*
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* xip_nopage() is invoked via the vma operations vector for a
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* mapped memory region to read in file data during a page fault.
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*
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* This function is derived from filemap_nopage, but used for execute in place
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*/
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static struct page *
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xip_file_nopage(struct vm_area_struct * area,
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unsigned long address,
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int *type)
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{
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struct file *file = area->vm_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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struct page *page;
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unsigned long size, pgoff, endoff;
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pgoff = ((address - area->vm_start) >> PAGE_CACHE_SHIFT)
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+ area->vm_pgoff;
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endoff = ((area->vm_end - area->vm_start) >> PAGE_CACHE_SHIFT)
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+ area->vm_pgoff;
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size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
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if (pgoff >= size) {
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return NULL;
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}
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page = mapping->a_ops->get_xip_page(mapping, pgoff*(PAGE_SIZE/512), 0);
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if (!IS_ERR(page)) {
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BUG_ON(!PageUptodate(page));
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return page;
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}
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if (PTR_ERR(page) != -ENODATA)
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return NULL;
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/* sparse block */
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if ((area->vm_flags & (VM_WRITE | VM_MAYWRITE)) &&
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(area->vm_flags & (VM_SHARED| VM_MAYSHARE)) &&
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(!(mapping->host->i_sb->s_flags & MS_RDONLY))) {
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/* maybe shared writable, allocate new block */
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page = mapping->a_ops->get_xip_page (mapping,
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pgoff*(PAGE_SIZE/512), 1);
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if (IS_ERR(page))
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return NULL;
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BUG_ON(!PageUptodate(page));
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/* unmap page at pgoff from all other vmas */
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__xip_unmap(mapping, pgoff);
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} else {
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/* not shared and writable, use empty_zero_page */
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page = virt_to_page(empty_zero_page);
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}
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return page;
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}
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static struct vm_operations_struct xip_file_vm_ops = {
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.nopage = xip_file_nopage,
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};
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int xip_file_mmap(struct file * file, struct vm_area_struct * vma)
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{
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BUG_ON(!file->f_mapping->a_ops->get_xip_page);
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file_accessed(file);
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vma->vm_ops = &xip_file_vm_ops;
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return 0;
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}
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EXPORT_SYMBOL_GPL(xip_file_mmap);
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static ssize_t
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do_xip_file_write(struct kiocb *iocb, const struct iovec *iov,
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unsigned long nr_segs, loff_t pos, loff_t *ppos,
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size_t count)
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{
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struct file *file = iocb->ki_filp;
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struct address_space * mapping = file->f_mapping;
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struct address_space_operations *a_ops = mapping->a_ops;
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struct inode *inode = mapping->host;
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long status = 0;
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struct page *page;
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size_t bytes;
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const struct iovec *cur_iov = iov; /* current iovec */
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size_t iov_base = 0; /* offset in the current iovec */
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char __user *buf;
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ssize_t written = 0;
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BUG_ON(!mapping->a_ops->get_xip_page);
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buf = iov->iov_base;
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do {
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unsigned long index;
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unsigned long offset;
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size_t copied;
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offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
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index = pos >> PAGE_CACHE_SHIFT;
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bytes = PAGE_CACHE_SIZE - offset;
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if (bytes > count)
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bytes = count;
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/*
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* Bring in the user page that we will copy from _first_.
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* Otherwise there's a nasty deadlock on copying from the
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* same page as we're writing to, without it being marked
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* up-to-date.
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*/
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fault_in_pages_readable(buf, bytes);
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page = a_ops->get_xip_page(mapping,
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index*(PAGE_SIZE/512), 0);
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if (IS_ERR(page) && (PTR_ERR(page) == -ENODATA)) {
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/* we allocate a new page unmap it */
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page = a_ops->get_xip_page(mapping,
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index*(PAGE_SIZE/512), 1);
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if (!IS_ERR(page))
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/* unmap page at pgoff from all other vmas */
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__xip_unmap(mapping, index);
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}
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if (IS_ERR(page)) {
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status = PTR_ERR(page);
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break;
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}
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BUG_ON(!PageUptodate(page));
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if (likely(nr_segs == 1))
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copied = filemap_copy_from_user(page, offset,
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buf, bytes);
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else
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copied = filemap_copy_from_user_iovec(page, offset,
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cur_iov, iov_base, bytes);
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flush_dcache_page(page);
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if (likely(copied > 0)) {
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status = copied;
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if (status >= 0) {
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written += status;
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count -= status;
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pos += status;
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buf += status;
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if (unlikely(nr_segs > 1))
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filemap_set_next_iovec(&cur_iov,
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&iov_base, status);
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}
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}
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if (unlikely(copied != bytes))
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if (status >= 0)
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status = -EFAULT;
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if (status < 0)
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break;
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} while (count);
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*ppos = pos;
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/*
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* No need to use i_size_read() here, the i_size
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* cannot change under us because we hold i_sem.
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*/
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if (pos > inode->i_size) {
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i_size_write(inode, pos);
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mark_inode_dirty(inode);
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}
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return written ? written : status;
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}
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|
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static ssize_t
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xip_file_aio_write_nolock(struct kiocb *iocb, const struct iovec *iov,
|
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unsigned long nr_segs, loff_t *ppos)
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{
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struct file *file = iocb->ki_filp;
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struct address_space * mapping = file->f_mapping;
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size_t ocount; /* original count */
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size_t count; /* after file limit checks */
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struct inode *inode = mapping->host;
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unsigned long seg;
|
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loff_t pos;
|
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ssize_t written;
|
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ssize_t err;
|
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|
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ocount = 0;
|
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for (seg = 0; seg < nr_segs; seg++) {
|
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const struct iovec *iv = &iov[seg];
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|
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/*
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* If any segment has a negative length, or the cumulative
|
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* length ever wraps negative then return -EINVAL.
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*/
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ocount += iv->iov_len;
|
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if (unlikely((ssize_t)(ocount|iv->iov_len) < 0))
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return -EINVAL;
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if (access_ok(VERIFY_READ, iv->iov_base, iv->iov_len))
|
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continue;
|
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if (seg == 0)
|
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return -EFAULT;
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nr_segs = seg;
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ocount -= iv->iov_len; /* This segment is no good */
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break;
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}
|
|
|
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count = ocount;
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pos = *ppos;
|
|
|
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vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
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|
|
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written = 0;
|
|
|
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err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
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if (err)
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goto out;
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|
|
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if (count == 0)
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goto out;
|
|
|
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err = remove_suid(file->f_dentry);
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if (err)
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goto out;
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|
|
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inode_update_time(inode, 1);
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|
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/* use execute in place to copy directly to disk */
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written = do_xip_file_write (iocb, iov,
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nr_segs, pos, ppos, count);
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out:
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return written ? written : err;
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}
|
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|
|
static ssize_t
|
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__xip_file_write_nolock(struct file *file, const struct iovec *iov,
|
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unsigned long nr_segs, loff_t *ppos)
|
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{
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struct kiocb kiocb;
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init_sync_kiocb(&kiocb, file);
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return xip_file_aio_write_nolock(&kiocb, iov, nr_segs, ppos);
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}
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|
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ssize_t
|
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xip_file_aio_write(struct kiocb *iocb, const char __user *buf,
|
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size_t count, loff_t pos)
|
|
{
|
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struct file *file = iocb->ki_filp;
|
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struct address_space *mapping = file->f_mapping;
|
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struct inode *inode = mapping->host;
|
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ssize_t ret;
|
|
struct iovec local_iov = { .iov_base = (void __user *)buf,
|
|
.iov_len = count };
|
|
|
|
BUG_ON(iocb->ki_pos != pos);
|
|
|
|
down(&inode->i_sem);
|
|
ret = xip_file_aio_write_nolock(iocb, &local_iov, 1, &iocb->ki_pos);
|
|
up(&inode->i_sem);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(xip_file_aio_write);
|
|
|
|
ssize_t xip_file_writev(struct file *file, const struct iovec *iov,
|
|
unsigned long nr_segs, loff_t *ppos)
|
|
{
|
|
struct address_space *mapping = file->f_mapping;
|
|
struct inode *inode = mapping->host;
|
|
ssize_t ret;
|
|
|
|
down(&inode->i_sem);
|
|
ret = __xip_file_write_nolock(file, iov, nr_segs, ppos);
|
|
up(&inode->i_sem);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(xip_file_writev);
|
|
|
|
/*
|
|
* truncate a page used for execute in place
|
|
* functionality is analog to block_truncate_page but does use get_xip_page
|
|
* to get the page instead of page cache
|
|
*/
|
|
int
|
|
xip_truncate_page(struct address_space *mapping, loff_t from)
|
|
{
|
|
pgoff_t index = from >> PAGE_CACHE_SHIFT;
|
|
unsigned offset = from & (PAGE_CACHE_SIZE-1);
|
|
unsigned blocksize;
|
|
unsigned length;
|
|
struct page *page;
|
|
void *kaddr;
|
|
int err;
|
|
|
|
BUG_ON(!mapping->a_ops->get_xip_page);
|
|
|
|
blocksize = 1 << mapping->host->i_blkbits;
|
|
length = offset & (blocksize - 1);
|
|
|
|
/* Block boundary? Nothing to do */
|
|
if (!length)
|
|
return 0;
|
|
|
|
length = blocksize - length;
|
|
|
|
page = mapping->a_ops->get_xip_page(mapping,
|
|
index*(PAGE_SIZE/512), 0);
|
|
err = -ENOMEM;
|
|
if (!page)
|
|
goto out;
|
|
if (unlikely(IS_ERR(page))) {
|
|
if (PTR_ERR(page) == -ENODATA) {
|
|
/* Hole? No need to truncate */
|
|
return 0;
|
|
} else {
|
|
err = PTR_ERR(page);
|
|
goto out;
|
|
}
|
|
} else
|
|
BUG_ON(!PageUptodate(page));
|
|
kaddr = kmap_atomic(page, KM_USER0);
|
|
memset(kaddr + offset, 0, length);
|
|
kunmap_atomic(kaddr, KM_USER0);
|
|
|
|
flush_dcache_page(page);
|
|
err = 0;
|
|
out:
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(xip_truncate_page);
|