[PATCH] xip: fs/mm: execute in place
authorCarsten Otte <cotte@de.ibm.com>
Fri, 24 Jun 2005 05:05:25 +0000 (22:05 -0700)
committerLinus Torvalds <torvalds@ppc970.osdl.org>
Fri, 24 Jun 2005 07:06:41 +0000 (00:06 -0700)
- 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>
fs/open.c
include/linux/fs.h
include/linux/rmap.h
mm/Makefile
mm/filemap.c
mm/filemap.h [new file with mode: 0644]
mm/filemap_xip.c [new file with mode: 0644]
mm/rmap.c

index 8ec63f735918d691d471bfc55bdb03c235b939b9..3f4a4286fdc4d7361c3f46d57b435863a0250494 100644 (file)
--- a/fs/open.c
+++ b/fs/open.c
@@ -808,7 +808,9 @@ struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags)
 
        /* NB: we're sure to have correct a_ops only after f_op->open */
        if (f->f_flags & O_DIRECT) {
-               if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO) {
+               if (!f->f_mapping->a_ops ||
+                   ((!f->f_mapping->a_ops->direct_IO) &&
+                   (!f->f_mapping->a_ops->get_xip_page))) {
                        fput(f);
                        f = ERR_PTR(-EINVAL);
                }
index 929bf8d20c8743e228a819b715355e1051f59bb1..79c0fafc021129554c974f1213fb67123e64d119 100644 (file)
@@ -330,6 +330,8 @@ struct address_space_operations {
        int (*releasepage) (struct page *, int);
        ssize_t (*direct_IO)(int, struct kiocb *, const struct iovec *iov,
                        loff_t offset, unsigned long nr_segs);
+       struct page* (*get_xip_page)(struct address_space *, sector_t,
+                       int);
 };
 
 struct backing_dev_info;
@@ -1497,6 +1499,22 @@ extern loff_t remote_llseek(struct file *file, loff_t offset, int origin);
 extern int generic_file_open(struct inode * inode, struct file * filp);
 extern int nonseekable_open(struct inode * inode, struct file * filp);
 
+#ifdef CONFIG_FS_XIP
+extern ssize_t xip_file_aio_read(struct kiocb *iocb, char __user *buf,
+                                size_t count, loff_t pos);
+extern ssize_t xip_file_readv(struct file *filp, const struct iovec *iov,
+                             unsigned long nr_segs, loff_t *ppos);
+extern ssize_t xip_file_sendfile(struct file *in_file, loff_t *ppos,
+                                size_t count, read_actor_t actor,
+                                void *target);
+extern int xip_file_mmap(struct file * file, struct vm_area_struct * vma);
+extern ssize_t xip_file_aio_write(struct kiocb *iocb, const char __user *buf,
+                                 size_t count, loff_t pos);
+extern ssize_t xip_file_writev(struct file *file, const struct iovec *iov,
+                              unsigned long nr_segs, loff_t *ppos);
+extern int xip_truncate_page(struct address_space *mapping, loff_t from);
+#endif
+
 static inline void do_generic_file_read(struct file * filp, loff_t *ppos,
                                        read_descriptor_t * desc,
                                        read_actor_t actor)
index 11b484e37ac94fcd2308a354d372f00faff8a736..e80fb7ee6efdf5617f49f439ac4eafe28e86dfc1 100644 (file)
@@ -92,6 +92,12 @@ static inline void page_dup_rmap(struct page *page)
 int page_referenced(struct page *, int is_locked, int ignore_token);
 int try_to_unmap(struct page *);
 
+/*
+ * Called from mm/filemap_xip.c to unmap empty zero page
+ */
+pte_t *page_check_address(struct page *, struct mm_struct *, unsigned long);
+
+
 /*
  * Used by swapoff to help locate where page is expected in vma.
  */
index 8f70ffd763c82ecf872ca5482fee373d1313c67b..4cd69e3ce4214996108e251b3ac9c505625f3419 100644 (file)
@@ -19,3 +19,4 @@ obj-$(CONFIG_SPARSEMEM)       += sparse.o
 obj-$(CONFIG_SHMEM) += shmem.o
 obj-$(CONFIG_TINY_SHMEM) += tiny-shmem.o
 
+obj-$(CONFIG_FS_XIP) += filemap_xip.o
index a3598b542a318609362248886027b5aabe48ba64..7332194d7afddfd816e27eaec2eebb17a4059a24 100644 (file)
@@ -28,6 +28,7 @@
 #include <linux/blkdev.h>
 #include <linux/security.h>
 #include <linux/syscalls.h>
+#include "filemap.h"
 /*
  * FIXME: remove all knowledge of the buffer layer from the core VM
  */
@@ -1714,32 +1715,7 @@ int remove_suid(struct dentry *dentry)
 }
 EXPORT_SYMBOL(remove_suid);
 
-/*
- * Copy as much as we can into the page and return the number of bytes which
- * were sucessfully copied.  If a fault is encountered then clear the page
- * out to (offset+bytes) and return the number of bytes which were copied.
- */
-static inline size_t
-filemap_copy_from_user(struct page *page, unsigned long offset,
-                       const char __user *buf, unsigned bytes)
-{
-       char *kaddr;
-       int left;
-
-       kaddr = kmap_atomic(page, KM_USER0);
-       left = __copy_from_user_inatomic(kaddr + offset, buf, bytes);
-       kunmap_atomic(kaddr, KM_USER0);
-
-       if (left != 0) {
-               /* Do it the slow way */
-               kaddr = kmap(page);
-               left = __copy_from_user(kaddr + offset, buf, bytes);
-               kunmap(page);
-       }
-       return bytes - left;
-}
-
-static size_t
+size_t
 __filemap_copy_from_user_iovec(char *vaddr, 
                        const struct iovec *iov, size_t base, size_t bytes)
 {
@@ -1766,52 +1742,6 @@ __filemap_copy_from_user_iovec(char *vaddr,
        return copied - left;
 }
 
-/*
- * This has the same sideeffects and return value as filemap_copy_from_user().
- * The difference is that on a fault we need to memset the remainder of the
- * page (out to offset+bytes), to emulate filemap_copy_from_user()'s
- * single-segment behaviour.
- */
-static inline size_t
-filemap_copy_from_user_iovec(struct page *page, unsigned long offset,
-                       const struct iovec *iov, size_t base, size_t bytes)
-{
-       char *kaddr;
-       size_t copied;
-
-       kaddr = kmap_atomic(page, KM_USER0);
-       copied = __filemap_copy_from_user_iovec(kaddr + offset, iov,
-                                               base, bytes);
-       kunmap_atomic(kaddr, KM_USER0);
-       if (copied != bytes) {
-               kaddr = kmap(page);
-               copied = __filemap_copy_from_user_iovec(kaddr + offset, iov,
-                                                       base, bytes);
-               kunmap(page);
-       }
-       return copied;
-}
-
-static inline void
-filemap_set_next_iovec(const struct iovec **iovp, size_t *basep, size_t bytes)
-{
-       const struct iovec *iov = *iovp;
-       size_t base = *basep;
-
-       while (bytes) {
-               int copy = min(bytes, iov->iov_len - base);
-
-               bytes -= copy;
-               base += copy;
-               if (iov->iov_len == base) {
-                       iov++;
-                       base = 0;
-               }
-       }
-       *iovp = iov;
-       *basep = base;
-}
-
 /*
  * Performs necessary checks before doing a write
  *
diff --git a/mm/filemap.h b/mm/filemap.h
new file mode 100644 (file)
index 0000000..c2d0546
--- /dev/null
@@ -0,0 +1,94 @@
+/*
+ *     linux/mm/filemap.h
+ *
+ * Copyright (C) 1994-1999  Linus Torvalds
+ */
+
+#ifndef __FILEMAP_H
+#define __FILEMAP_H
+
+#include <linux/types.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/highmem.h>
+#include <linux/uio.h>
+#include <linux/config.h>
+#include <asm/uaccess.h>
+
+extern size_t
+__filemap_copy_from_user_iovec(char *vaddr,
+                              const struct iovec *iov,
+                              size_t base,
+                              size_t bytes);
+
+/*
+ * Copy as much as we can into the page and return the number of bytes which
+ * were sucessfully copied.  If a fault is encountered then clear the page
+ * out to (offset+bytes) and return the number of bytes which were copied.
+ */
+static inline size_t
+filemap_copy_from_user(struct page *page, unsigned long offset,
+                       const char __user *buf, unsigned bytes)
+{
+       char *kaddr;
+       int left;
+
+       kaddr = kmap_atomic(page, KM_USER0);
+       left = __copy_from_user_inatomic(kaddr + offset, buf, bytes);
+       kunmap_atomic(kaddr, KM_USER0);
+
+       if (left != 0) {
+               /* Do it the slow way */
+               kaddr = kmap(page);
+               left = __copy_from_user(kaddr + offset, buf, bytes);
+               kunmap(page);
+       }
+       return bytes - left;
+}
+
+/*
+ * This has the same sideeffects and return value as filemap_copy_from_user().
+ * The difference is that on a fault we need to memset the remainder of the
+ * page (out to offset+bytes), to emulate filemap_copy_from_user()'s
+ * single-segment behaviour.
+ */
+static inline size_t
+filemap_copy_from_user_iovec(struct page *page, unsigned long offset,
+                       const struct iovec *iov, size_t base, size_t bytes)
+{
+       char *kaddr;
+       size_t copied;
+
+       kaddr = kmap_atomic(page, KM_USER0);
+       copied = __filemap_copy_from_user_iovec(kaddr + offset, iov,
+                                               base, bytes);
+       kunmap_atomic(kaddr, KM_USER0);
+       if (copied != bytes) {
+               kaddr = kmap(page);
+               copied = __filemap_copy_from_user_iovec(kaddr + offset, iov,
+                                                       base, bytes);
+               kunmap(page);
+       }
+       return copied;
+}
+
+static inline void
+filemap_set_next_iovec(const struct iovec **iovp, size_t *basep, size_t bytes)
+{
+       const struct iovec *iov = *iovp;
+       size_t base = *basep;
+
+       while (bytes) {
+               int copy = min(bytes, iov->iov_len - base);
+
+               bytes -= copy;
+               base += copy;
+               if (iov->iov_len == base) {
+                       iov++;
+                       base = 0;
+               }
+       }
+       *iovp = iov;
+       *basep = base;
+}
+#endif
diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
new file mode 100644 (file)
index 0000000..7d63acd
--- /dev/null
@@ -0,0 +1,581 @@
+/*
+ *     linux/mm/filemap_xip.c
+ *
+ * Copyright (C) 2005 IBM Corporation
+ * Author: Carsten Otte <cotte@de.ibm.com>
+ *
+ * derived from linux/mm/filemap.c - Copyright (C) Linus Torvalds
+ *
+ */
+
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/module.h>
+#include <linux/uio.h>
+#include <linux/rmap.h>
+#include <asm/tlbflush.h>
+#include "filemap.h"
+
+/*
+ * This is a file read routine for execute in place files, and uses
+ * the mapping->a_ops->get_xip_page() function for the actual low-level
+ * stuff.
+ *
+ * Note the struct file* is not used at all.  It may be NULL.
+ */
+static void
+do_xip_mapping_read(struct address_space *mapping,
+                   struct file_ra_state *_ra,
+                   struct file *filp,
+                   loff_t *ppos,
+                   read_descriptor_t *desc,
+                   read_actor_t actor)
+{
+       struct inode *inode = mapping->host;
+       unsigned long index, end_index, offset;
+       loff_t isize;
+
+       BUG_ON(!mapping->a_ops->get_xip_page);
+
+       index = *ppos >> PAGE_CACHE_SHIFT;
+       offset = *ppos & ~PAGE_CACHE_MASK;
+
+       isize = i_size_read(inode);
+       if (!isize)
+               goto out;
+
+       end_index = (isize - 1) >> PAGE_CACHE_SHIFT;
+       for (;;) {
+               struct page *page;
+               unsigned long nr, ret;
+
+               /* nr is the maximum number of bytes to copy from this page */
+               nr = PAGE_CACHE_SIZE;
+               if (index >= end_index) {
+                       if (index > end_index)
+                               goto out;
+                       nr = ((isize - 1) & ~PAGE_CACHE_MASK) + 1;
+                       if (nr <= offset) {
+                               goto out;
+                       }
+               }
+               nr = nr - offset;
+
+               page = mapping->a_ops->get_xip_page(mapping,
+                       index*(PAGE_SIZE/512), 0);
+               if (!page)
+                       goto no_xip_page;
+               if (unlikely(IS_ERR(page))) {
+                       if (PTR_ERR(page) == -ENODATA) {
+                               /* sparse */
+                               page = virt_to_page(empty_zero_page);
+                       } else {
+                               desc->error = PTR_ERR(page);
+                               goto out;
+                       }
+               } else
+                       BUG_ON(!PageUptodate(page));
+
+               /* If users can be writing to this page using arbitrary
+                * virtual addresses, take care about potential aliasing
+                * before reading the page on the kernel side.
+                */
+               if (mapping_writably_mapped(mapping))
+                       flush_dcache_page(page);
+
+               /*
+                * Ok, we have the page, and it's up-to-date, so
+                * now we can copy it to user space...
+                *
+                * The actor routine returns how many bytes were actually used..
+                * NOTE! This may not be the same as how much of a user buffer
+                * we filled up (we may be padding etc), so we can only update
+                * "pos" here (the actor routine has to update the user buffer
+                * pointers and the remaining count).
+                */
+               ret = actor(desc, page, offset, nr);
+               offset += ret;
+               index += offset >> PAGE_CACHE_SHIFT;
+               offset &= ~PAGE_CACHE_MASK;
+
+               if (ret == nr && desc->count)
+                       continue;
+               goto out;
+
+no_xip_page:
+               /* Did not get the page. Report it */
+               desc->error = -EIO;
+               goto out;
+       }
+
+out:
+       *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset;
+       if (filp)
+               file_accessed(filp);
+}
+
+/*
+ * This is the "read()" routine for all filesystems
+ * that uses the get_xip_page address space operation.
+ */
+static ssize_t
+__xip_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
+               unsigned long nr_segs, loff_t *ppos)
+{
+       struct file *filp = iocb->ki_filp;
+       ssize_t retval;
+       unsigned long seg;
+       size_t count;
+
+       count = 0;
+       for (seg = 0; seg < nr_segs; seg++) {
+               const struct iovec *iv = &iov[seg];
+
+               /*
+                * If any segment has a negative length, or the cumulative
+                * length ever wraps negative then return -EINVAL.
+                */
+               count += iv->iov_len;
+               if (unlikely((ssize_t)(count|iv->iov_len) < 0))
+                       return -EINVAL;
+               if (access_ok(VERIFY_WRITE, iv->iov_base, iv->iov_len))
+                       continue;
+               if (seg == 0)
+                       return -EFAULT;
+               nr_segs = seg;
+               count -= iv->iov_len;   /* This segment is no good */
+               break;
+       }
+
+       retval = 0;
+       if (count) {
+               for (seg = 0; seg < nr_segs; seg++) {
+                       read_descriptor_t desc;
+
+                       desc.written = 0;
+                       desc.arg.buf = iov[seg].iov_base;
+                       desc.count = iov[seg].iov_len;
+                       if (desc.count == 0)
+                               continue;
+                       desc.error = 0;
+                       do_xip_mapping_read(filp->f_mapping, &filp->f_ra, filp,
+                                           ppos, &desc, file_read_actor);
+                       retval += desc.written;
+                       if (!retval) {
+                               retval = desc.error;
+                               break;
+                       }
+               }
+       }
+       return retval;
+}
+
+ssize_t
+xip_file_aio_read(struct kiocb *iocb, char __user *buf, size_t count,
+                 loff_t pos)
+{
+       struct iovec local_iov = { .iov_base = buf, .iov_len = count };
+
+       BUG_ON(iocb->ki_pos != pos);
+       return __xip_file_aio_read(iocb, &local_iov, 1, &iocb->ki_pos);
+}
+EXPORT_SYMBOL_GPL(xip_file_aio_read);
+
+ssize_t
+xip_file_readv(struct file *filp, const struct iovec *iov,
+              unsigned long nr_segs, loff_t *ppos)
+{
+       struct kiocb kiocb;
+
+       init_sync_kiocb(&kiocb, filp);
+       return __xip_file_aio_read(&kiocb, iov, nr_segs, ppos);
+}
+EXPORT_SYMBOL_GPL(xip_file_readv);
+
+ssize_t
+xip_file_sendfile(struct file *in_file, loff_t *ppos,
+            size_t count, read_actor_t actor, void *target)
+{
+       read_descriptor_t desc;
+
+       if (!count)
+               return 0;
+
+       desc.written = 0;
+       desc.count = count;
+       desc.arg.data = target;
+       desc.error = 0;
+
+       do_xip_mapping_read(in_file->f_mapping, &in_file->f_ra, in_file,
+                           ppos, &desc, actor);
+       if (desc.written)
+               return desc.written;
+       return desc.error;
+}
+EXPORT_SYMBOL_GPL(xip_file_sendfile);
+
+/*
+ * __xip_unmap is invoked from xip_unmap and
+ * xip_write
+ *
+ * This function walks all vmas of the address_space and unmaps the
+ * empty_zero_page when found at pgoff. Should it go in rmap.c?
+ */
+static void
+__xip_unmap (struct address_space * mapping,
+                    unsigned long pgoff)
+{
+       struct vm_area_struct *vma;
+       struct mm_struct *mm;
+       struct prio_tree_iter iter;
+       unsigned long address;
+       pte_t *pte;
+       pte_t pteval;
+
+       spin_lock(&mapping->i_mmap_lock);
+       vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
+               mm = vma->vm_mm;
+               address = vma->vm_start +
+                       ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
+               BUG_ON(address < vma->vm_start || address >= vma->vm_end);
+               /*
+                * We need the page_table_lock to protect us from page faults,
+                * munmap, fork, etc...
+                */
+               pte = page_check_address(virt_to_page(empty_zero_page), mm,
+                                        address);
+               if (!IS_ERR(pte)) {
+                       /* Nuke the page table entry. */
+                       flush_cache_page(vma, address, pte_pfn(pte));
+                       pteval = ptep_clear_flush(vma, address, pte);
+                       BUG_ON(pte_dirty(pteval));
+                       pte_unmap(pte);
+                       spin_unlock(&mm->page_table_lock);
+               }
+       }
+       spin_unlock(&mapping->i_mmap_lock);
+}
+
+/*
+ * xip_nopage() is invoked via the vma operations vector for a
+ * mapped memory region to read in file data during a page fault.
+ *
+ * This function is derived from filemap_nopage, but used for execute in place
+ */
+static struct page *
+xip_file_nopage(struct vm_area_struct * area,
+                  unsigned long address,
+                  int *type)
+{
+       struct file *file = area->vm_file;
+       struct address_space *mapping = file->f_mapping;
+       struct inode *inode = mapping->host;
+       struct page *page;
+       unsigned long size, pgoff, endoff;
+
+       pgoff = ((address - area->vm_start) >> PAGE_CACHE_SHIFT)
+               + area->vm_pgoff;
+       endoff = ((area->vm_end - area->vm_start) >> PAGE_CACHE_SHIFT)
+               + area->vm_pgoff;
+
+       size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+       if (pgoff >= size) {
+               return NULL;
+       }
+
+       page = mapping->a_ops->get_xip_page(mapping, pgoff*(PAGE_SIZE/512), 0);
+       if (!IS_ERR(page)) {
+               BUG_ON(!PageUptodate(page));
+               return page;
+       }
+       if (PTR_ERR(page) != -ENODATA)
+               return NULL;
+
+       /* sparse block */
+       if ((area->vm_flags & (VM_WRITE | VM_MAYWRITE)) &&
+           (area->vm_flags & (VM_SHARED| VM_MAYSHARE)) &&
+           (!(mapping->host->i_sb->s_flags & MS_RDONLY))) {
+               /* maybe shared writable, allocate new block */
+               page = mapping->a_ops->get_xip_page (mapping,
+                       pgoff*(PAGE_SIZE/512), 1);
+               if (IS_ERR(page))
+                       return NULL;
+               BUG_ON(!PageUptodate(page));
+               /* unmap page at pgoff from all other vmas */
+               __xip_unmap(mapping, pgoff);
+       } else {
+               /* not shared and writable, use empty_zero_page */
+               page = virt_to_page(empty_zero_page);
+       }
+
+       return page;
+}
+
+static struct vm_operations_struct xip_file_vm_ops = {
+       .nopage         = xip_file_nopage,
+};
+
+int xip_file_mmap(struct file * file, struct vm_area_struct * vma)
+{
+       BUG_ON(!file->f_mapping->a_ops->get_xip_page);
+
+       file_accessed(file);
+       vma->vm_ops = &xip_file_vm_ops;
+       return 0;
+}
+EXPORT_SYMBOL_GPL(xip_file_mmap);
+
+static ssize_t
+do_xip_file_write(struct kiocb *iocb, const struct iovec *iov,
+                 unsigned long nr_segs, loff_t pos, loff_t *ppos,
+                 size_t count)
+{
+       struct file *file = iocb->ki_filp;
+       struct address_space * mapping = file->f_mapping;
+       struct address_space_operations *a_ops = mapping->a_ops;
+       struct inode    *inode = mapping->host;
+       long            status = 0;
+       struct page     *page;
+       size_t          bytes;
+       const struct iovec *cur_iov = iov; /* current iovec */
+       size_t          iov_base = 0;      /* offset in the current iovec */
+       char __user     *buf;
+       ssize_t         written = 0;
+
+       BUG_ON(!mapping->a_ops->get_xip_page);
+
+       buf = iov->iov_base;
+       do {
+               unsigned long index;
+               unsigned long offset;
+               size_t copied;
+
+               offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
+               index = pos >> PAGE_CACHE_SHIFT;
+               bytes = PAGE_CACHE_SIZE - offset;
+               if (bytes > count)
+                       bytes = count;
+
+               /*
+                * Bring in the user page that we will copy from _first_.
+                * Otherwise there's a nasty deadlock on copying from the
+                * same page as we're writing to, without it being marked
+                * up-to-date.
+                */
+               fault_in_pages_readable(buf, bytes);
+
+               page = a_ops->get_xip_page(mapping,
+                                                   index*(PAGE_SIZE/512), 0);
+               if (IS_ERR(page) && (PTR_ERR(page) == -ENODATA)) {
+                       /* we allocate a new page unmap it */
+                       page = a_ops->get_xip_page(mapping,
+                               index*(PAGE_SIZE/512), 1);
+                       if (!IS_ERR(page))
+                       /* unmap page at pgoff from all other vmas */
+                       __xip_unmap(mapping, index);
+
+               }
+
+               if (IS_ERR(page)) {
+                       status = PTR_ERR(page);
+                       break;
+               }
+
+               BUG_ON(!PageUptodate(page));
+
+               if (likely(nr_segs == 1))
+                       copied = filemap_copy_from_user(page, offset,
+                                                       buf, bytes);
+               else
+                       copied = filemap_copy_from_user_iovec(page, offset,
+                                               cur_iov, iov_base, bytes);
+               flush_dcache_page(page);
+               if (likely(copied > 0)) {
+                       status = copied;
+
+                       if (status >= 0) {
+                               written += status;
+                               count -= status;
+                               pos += status;
+                               buf += status;
+                               if (unlikely(nr_segs > 1))
+                                       filemap_set_next_iovec(&cur_iov,
+                                                       &iov_base, status);
+                       }
+               }
+               if (unlikely(copied != bytes))
+                       if (status >= 0)
+                               status = -EFAULT;
+               if (status < 0)
+                       break;
+       } while (count);
+       *ppos = pos;
+       /*
+        * No need to use i_size_read() here, the i_size
+        * cannot change under us because we hold i_sem.
+        */
+       if (pos > inode->i_size) {
+               i_size_write(inode, pos);
+               mark_inode_dirty(inode);
+       }
+
+       return written ? written : status;
+}
+
+static ssize_t
+xip_file_aio_write_nolock(struct kiocb *iocb, const struct iovec *iov,
+                               unsigned long nr_segs, loff_t *ppos)
+{
+       struct file *file = iocb->ki_filp;
+       struct address_space * mapping = file->f_mapping;
+       size_t ocount;          /* original count */
+       size_t count;           /* after file limit checks */
+       struct inode    *inode = mapping->host;
+       unsigned long   seg;
+       loff_t          pos;
+       ssize_t         written;
+       ssize_t         err;
+
+       ocount = 0;
+       for (seg = 0; seg < nr_segs; seg++) {
+               const struct iovec *iv = &iov[seg];
+
+               /*
+                * If any segment has a negative length, or the cumulative
+                * length ever wraps negative then return -EINVAL.
+                */
+               ocount += iv->iov_len;
+               if (unlikely((ssize_t)(ocount|iv->iov_len) < 0))
+                       return -EINVAL;
+               if (access_ok(VERIFY_READ, iv->iov_base, iv->iov_len))
+                       continue;
+               if (seg == 0)
+                       return -EFAULT;
+               nr_segs = seg;
+               ocount -= iv->iov_len;  /* This segment is no good */
+               break;
+       }
+
+       count = ocount;
+       pos = *ppos;
+
+       vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
+
+       written = 0;
+
+       err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
+       if (err)
+               goto out;
+
+       if (count == 0)
+               goto out;
+
+       err = remove_suid(file->f_dentry);
+       if (err)
+               goto out;
+
+       inode_update_time(inode, 1);
+
+       /* use execute in place to copy directly to disk */
+       written = do_xip_file_write (iocb, iov,
+                                 nr_segs, pos, ppos, count);
+ out:
+       return written ? written : err;
+}
+
+static ssize_t
+__xip_file_write_nolock(struct file *file, const struct iovec *iov,
+                       unsigned long nr_segs, loff_t *ppos)
+{
+       struct kiocb kiocb;
+
+       init_sync_kiocb(&kiocb, file);
+       return xip_file_aio_write_nolock(&kiocb, iov, nr_segs, ppos);
+}
+
+ssize_t
+xip_file_aio_write(struct kiocb *iocb, const char __user *buf,
+                      size_t count, loff_t pos)
+{
+       struct file *file = iocb->ki_filp;
+       struct address_space *mapping = file->f_mapping;
+       struct inode *inode = mapping->host;
+       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);
index 89770bd25f31be71877813a292793fcc62e01116..08ac5c7fa91fa02b42c03515749fb43ff057554e 100644 (file)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -247,8 +247,8 @@ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
  *
  * On success returns with mapped pte and locked mm->page_table_lock.
  */
-static pte_t *page_check_address(struct page *page, struct mm_struct *mm,
-                                       unsigned long address)
+pte_t *page_check_address(struct page *page, struct mm_struct *mm,
+                         unsigned long address)
 {
        pgd_t *pgd;
        pud_t *pud;