The patch titled
mm: tiny-shmem nommu fix
has been added to the -mm tree. Its filename is
mm-tiny-shmem-nommu-fix.patch
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------------------------------------------------------
Subject: mm: tiny-shmem nommu fix
From: Nick Piggin <npiggin@xxxxxxx>
The previous patch db203d53d474aa068984e409d807628f5841da1b ("mm:
tiny-shmem fix lock ordering: mmap_sem vs i_mutex") to fix the lock
ordering in tiny-shmem breaks shared anonymous and IPC memory on NOMMU
architectures because it was using the expanding truncate to signal ramfs
to allocate a physically contiguous RAM backing the inode (otherwise it is
unusable for "memory mapping" it to userspace).
However do_truncate is what caused the lock ordering error, due to it
taking i_mutex. In this case, we can actually just call ramfs directly to
allocate memory for the mapping, rather than go via truncate.
Acked-by: David Howells <dhowells@xxxxxxxxxx>
Acked-by: Hugh Dickins <hugh@xxxxxxxxxxx>
Signed-off-by: Nick Piggin <npiggin@xxxxxxx>
Cc: Matt Mackall <mpm@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/ramfs/file-nommu.c | 2 +-
include/linux/ramfs.h | 1 +
mm/tiny-shmem.c | 6 ++++++
3 files changed, 8 insertions(+), 1 deletion(-)
diff -puN fs/ramfs/file-nommu.c~mm-tiny-shmem-nommu-fix fs/ramfs/file-nommu.c
--- a/fs/ramfs/file-nommu.c~mm-tiny-shmem-nommu-fix
+++ a/fs/ramfs/file-nommu.c
@@ -58,7 +58,7 @@ const struct inode_operations ramfs_file
* size 0 on the assumption that it's going to be used for an mmap of shared
* memory
*/
-static int ramfs_nommu_expand_for_mapping(struct inode *inode, size_t newsize)
+int ramfs_nommu_expand_for_mapping(struct inode *inode, size_t newsize)
{
struct pagevec lru_pvec;
unsigned long npages, xpages, loop, limit;
diff -puN include/linux/ramfs.h~mm-tiny-shmem-nommu-fix include/linux/ramfs.h
--- a/include/linux/ramfs.h~mm-tiny-shmem-nommu-fix
+++ a/include/linux/ramfs.h
@@ -6,6 +6,7 @@ extern int ramfs_get_sb(struct file_syst
int flags, const char *dev_name, void *data, struct vfsmount *mnt);
#ifndef CONFIG_MMU
+extern int ramfs_nommu_expand_for_mapping(struct inode *inode, size_t newsize);
extern unsigned long ramfs_nommu_get_unmapped_area(struct file *file,
unsigned long addr,
unsigned long len,
diff -puN mm/tiny-shmem.c~mm-tiny-shmem-nommu-fix mm/tiny-shmem.c
--- a/mm/tiny-shmem.c~mm-tiny-shmem-nommu-fix
+++ a/mm/tiny-shmem.c
@@ -80,6 +80,12 @@ struct file *shmem_file_setup(char *name
inode->i_nlink = 0; /* It is unlinked */
init_file(file, shm_mnt, dentry, FMODE_WRITE | FMODE_READ,
&ramfs_file_operations);
+
+#ifndef CONFIG_MMU
+ error = ramfs_nommu_expand_for_mapping(inode, size);
+ if (error)
+ goto close_file;
+#endif
return file;
close_file:
_
Patches currently in -mm which might be from npiggin@xxxxxxx are
inotify-fix-lock-ordering-wrt-do_page_faults-mmap_sem.patch
mm-tiny-shmem-nommu-fix.patch
git-x86.patch
git-cifs.patch
vmscan-move-isolate_lru_page-to-vmscanc.patch
mlock-mlocked-pages-are-unevictable.patch
mlock-mlocked-pages-are-unevictable-fix.patch
mmap-handle-mlocked-pages-during-map-remap-unmap.patch
vmstat-mlocked-pages-statistics.patch
mm-pagecache-insertion-fewer-atomics.patch
mm-unlockless-reclaim.patch
mm-page-lock-use-lock-bitops.patch
fs-buffer-lock-use-lock-bitops.patch
mm-page-allocator-minor-speedup.patch
mm-rewrite-vmap-layer.patch
mm-rewrite-vmap-layer-fix.patch
mm-rewrite-vmap-layer-fix-fix.patch
mm-rewrite-vmap-layer-fix-fix-fix.patch
reiser4.patch
likeliness-accounting-change-and-cleanup.patch
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