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4b19de6d1c
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@redhat.com>
Acked-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
24 lines
784 B
C
24 lines
784 B
C
#ifndef _LINUX_RAMFS_H
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#define _LINUX_RAMFS_H
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struct inode *ramfs_get_inode(struct super_block *sb, int mode, dev_t dev);
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extern int ramfs_get_sb(struct file_system_type *fs_type,
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int flags, const char *dev_name, void *data, struct vfsmount *mnt);
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#ifndef CONFIG_MMU
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extern int ramfs_nommu_expand_for_mapping(struct inode *inode, size_t newsize);
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extern unsigned long ramfs_nommu_get_unmapped_area(struct file *file,
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unsigned long addr,
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unsigned long len,
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unsigned long pgoff,
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unsigned long flags);
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extern int ramfs_nommu_mmap(struct file *file, struct vm_area_struct *vma);
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#endif
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extern const struct file_operations ramfs_file_operations;
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extern struct vm_operations_struct generic_file_vm_ops;
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extern int __init init_rootfs(void);
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#endif
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