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authorMatthew Wilcox <matthew.r.wilcox@intel.com>2015-02-16 23:59:02 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2015-02-17 01:56:03 (GMT)
commitf7ca90b160307d63aaedab8bd451c24a182db20f (patch)
tree687eb94acbc8ebfab6d5e12a57dc336ce21b7c64 /mm
parent289c6aedac981533331428bc933fff21ae332c9e (diff)
dax,ext2: replace the XIP page fault handler with the DAX page fault handler
Instead of calling aops->get_xip_mem from the fault handler, the filesystem passes a get_block_t that is used to find the appropriate blocks. This requires that all architectures implement copy_user_page(). At the time of writing, mips and arm do not. Patches exist and are in progress. [akpm@linux-foundation.org: remap_file_pages went away] Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Andreas Dilger <andreas.dilger@intel.com> Cc: Boaz Harrosh <boaz@plexistor.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/filemap_xip.c206
1 files changed, 0 insertions, 206 deletions
diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
index 9c869f4..59fb387 100644
--- a/mm/filemap_xip.c
+++ b/mm/filemap_xip.c
@@ -23,212 +23,6 @@
#include <asm/io.h>
/*
- * We do use our own empty page to avoid interference with other users
- * of ZERO_PAGE(), such as /dev/zero
- */
-static DEFINE_MUTEX(xip_sparse_mutex);
-static seqcount_t xip_sparse_seq = SEQCNT_ZERO(xip_sparse_seq);
-static struct page *__xip_sparse_page;
-
-/* called under xip_sparse_mutex */
-static struct page *xip_sparse_page(void)
-{
- if (!__xip_sparse_page) {
- struct page *page = alloc_page(GFP_HIGHUSER | __GFP_ZERO);
-
- if (page)
- __xip_sparse_page = page;
- }
- return __xip_sparse_page;
-}
-
-/*
- * __xip_unmap is invoked from xip_unmap and xip_write
- *
- * This function walks all vmas of the address_space and unmaps the
- * __xip_sparse_page when found at pgoff.
- */
-static void __xip_unmap(struct address_space * mapping, unsigned long pgoff)
-{
- struct vm_area_struct *vma;
- struct page *page;
- unsigned count;
- int locked = 0;
-
- count = read_seqcount_begin(&xip_sparse_seq);
-
- page = __xip_sparse_page;
- if (!page)
- return;
-
-retry:
- i_mmap_lock_read(mapping);
- vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
- pte_t *pte, pteval;
- spinlock_t *ptl;
- struct mm_struct *mm = vma->vm_mm;
- unsigned long address = vma->vm_start +
- ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
-
- BUG_ON(address < vma->vm_start || address >= vma->vm_end);
- pte = page_check_address(page, mm, address, &ptl, 1);
- if (pte) {
- /* Nuke the page table entry. */
- flush_cache_page(vma, address, pte_pfn(*pte));
- pteval = ptep_clear_flush(vma, address, pte);
- page_remove_rmap(page);
- dec_mm_counter(mm, MM_FILEPAGES);
- BUG_ON(pte_dirty(pteval));
- pte_unmap_unlock(pte, ptl);
- /* must invalidate_page _before_ freeing the page */
- mmu_notifier_invalidate_page(mm, address);
- page_cache_release(page);
- }
- }
- i_mmap_unlock_read(mapping);
-
- if (locked) {
- mutex_unlock(&xip_sparse_mutex);
- } else if (read_seqcount_retry(&xip_sparse_seq, count)) {
- mutex_lock(&xip_sparse_mutex);
- locked = 1;
- goto retry;
- }
-}
-
-/*
- * xip_fault() 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_fault, but used for execute in place
- */
-static int xip_file_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
-{
- struct file *file = vma->vm_file;
- struct address_space *mapping = file->f_mapping;
- struct inode *inode = mapping->host;
- pgoff_t size;
- void *xip_mem;
- unsigned long xip_pfn;
- struct page *page;
- int error;
-
- /* XXX: are VM_FAULT_ codes OK? */
-again:
- size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
- if (vmf->pgoff >= size)
- return VM_FAULT_SIGBUS;
-
- error = mapping->a_ops->get_xip_mem(mapping, vmf->pgoff, 0,
- &xip_mem, &xip_pfn);
- if (likely(!error))
- goto found;
- if (error != -ENODATA)
- return VM_FAULT_OOM;
-
- /* sparse block */
- if ((vma->vm_flags & (VM_WRITE | VM_MAYWRITE)) &&
- (vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) &&
- (!(mapping->host->i_sb->s_flags & MS_RDONLY))) {
- int err;
-
- /* maybe shared writable, allocate new block */
- mutex_lock(&xip_sparse_mutex);
- error = mapping->a_ops->get_xip_mem(mapping, vmf->pgoff, 1,
- &xip_mem, &xip_pfn);
- mutex_unlock(&xip_sparse_mutex);
- if (error)
- return VM_FAULT_SIGBUS;
- /* unmap sparse mappings at pgoff from all other vmas */
- __xip_unmap(mapping, vmf->pgoff);
-
-found:
- /*
- * We must recheck i_size under i_mmap_rwsem to prevent races
- * with truncation
- */
- i_mmap_lock_read(mapping);
- size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
- PAGE_CACHE_SHIFT;
- if (unlikely(vmf->pgoff >= size)) {
- i_mmap_unlock_read(mapping);
- return VM_FAULT_SIGBUS;
- }
- err = vm_insert_mixed(vma, (unsigned long)vmf->virtual_address,
- xip_pfn);
- i_mmap_unlock_read(mapping);
- if (err == -ENOMEM)
- return VM_FAULT_OOM;
- /*
- * err == -EBUSY is fine, we've raced against another thread
- * that faulted-in the same page
- */
- if (err != -EBUSY)
- BUG_ON(err);
- return VM_FAULT_NOPAGE;
- } else {
- int err, ret = VM_FAULT_OOM;
-
- mutex_lock(&xip_sparse_mutex);
- write_seqcount_begin(&xip_sparse_seq);
- error = mapping->a_ops->get_xip_mem(mapping, vmf->pgoff, 0,
- &xip_mem, &xip_pfn);
- if (unlikely(!error)) {
- write_seqcount_end(&xip_sparse_seq);
- mutex_unlock(&xip_sparse_mutex);
- goto again;
- }
- if (error != -ENODATA)
- goto out;
-
- /*
- * We must recheck i_size under i_mmap_rwsem to prevent races
- * with truncation
- */
- i_mmap_lock_read(mapping);
- size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
- PAGE_CACHE_SHIFT;
- if (unlikely(vmf->pgoff >= size)) {
- ret = VM_FAULT_SIGBUS;
- goto unlock;
- }
- /* not shared and writable, use xip_sparse_page() */
- page = xip_sparse_page();
- if (!page)
- goto unlock;
- err = vm_insert_page(vma, (unsigned long)vmf->virtual_address,
- page);
- if (err == -ENOMEM)
- goto unlock;
-
- ret = VM_FAULT_NOPAGE;
-unlock:
- i_mmap_unlock_read(mapping);
-out:
- write_seqcount_end(&xip_sparse_seq);
- mutex_unlock(&xip_sparse_mutex);
-
- return ret;
- }
-}
-
-static const struct vm_operations_struct xip_file_vm_ops = {
- .fault = xip_file_fault,
- .page_mkwrite = filemap_page_mkwrite,
-};
-
-int xip_file_mmap(struct file * file, struct vm_area_struct * vma)
-{
- BUG_ON(!file->f_mapping->a_ops->get_xip_mem);
-
- file_accessed(file);
- vma->vm_ops = &xip_file_vm_ops;
- vma->vm_flags |= VM_MIXEDMAP;
- return 0;
-}
-EXPORT_SYMBOL_GPL(xip_file_mmap);
-
-/*
* truncate a page used for execute in place
* functionality is analog to block_truncate_page but does use get_xip_mem
* to get the page instead of page cache

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