From 25d9e2d15286281ec834b829a4aaf8969011f1cd Mon Sep 17 00:00:00 2001 From: "npiggin@suse.de" Date: Fri, 21 Aug 2009 02:35:05 +1000 Subject: truncate: new helpers Introduce new truncate helpers truncate_pagecache and inode_newsize_ok. vmtruncate is also consolidated from mm/memory.c and mm/nommu.c and into mm/truncate.c. Reviewed-by: Christoph Hellwig Signed-off-by: Nick Piggin Signed-off-by: Al Viro --- mm/nommu.c | 40 ---------------------------------------- 1 file changed, 40 deletions(-) (limited to 'mm/nommu.c') diff --git a/mm/nommu.c b/mm/nommu.c index 8d484241d03..56a446f0597 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -82,46 +82,6 @@ DECLARE_RWSEM(nommu_region_sem); struct vm_operations_struct generic_file_vm_ops = { }; -/* - * Handle all mappings that got truncated by a "truncate()" - * system call. - * - * NOTE! We have to be ready to update the memory sharing - * between the file and the memory map for a potential last - * incomplete page. Ugly, but necessary. - */ -int vmtruncate(struct inode *inode, loff_t offset) -{ - struct address_space *mapping = inode->i_mapping; - unsigned long limit; - - if (inode->i_size < offset) - goto do_expand; - i_size_write(inode, offset); - - truncate_inode_pages(mapping, offset); - goto out_truncate; - -do_expand: - limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; - if (limit != RLIM_INFINITY && offset > limit) - goto out_sig; - if (offset > inode->i_sb->s_maxbytes) - goto out; - i_size_write(inode, offset); - -out_truncate: - if (inode->i_op->truncate) - inode->i_op->truncate(inode); - return 0; -out_sig: - send_sig(SIGXFSZ, current, 0); -out: - return -EFBIG; -} - -EXPORT_SYMBOL(vmtruncate); - /* * Return the total memory allocated for this pointer, not * just what the caller asked for. -- cgit v1.2.3 From 645d83c5db970a1c57225e155113b4aa2451e920 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 24 Sep 2009 15:13:10 +0100 Subject: NOMMU: Fix MAP_PRIVATE mmap() of objects where the data can be mapped directly Fix MAP_PRIVATE mmap() of files and devices where the data in the backing store might be mapped directly. Use the BDI_CAP_MAP_DIRECT capability flag to govern whether or not we should be trying to map a file directly. This can be used to determine whether or not a region has been filled in at the point where we call do_mmap_shared() or do_mmap_private(). The BDI_CAP_MAP_DIRECT capability flag is cleared by validate_mmap_request() if there's any reason we can't use it. It's also cleared in do_mmap_pgoff() if f_op->get_unmapped_area() fails. Without this fix, attempting to run a program from a RomFS image on a non-mappable MTD partition results in a BUG as the kernel attempts XIP, and this can be caught in gdb: Program received signal SIGABRT, Aborted. 0xc005dce8 in add_nommu_region (region=) at mm/nommu.c:547 (gdb) bt #0 0xc005dce8 in add_nommu_region (region=) at mm/nommu.c:547 #1 0xc005f168 in do_mmap_pgoff (file=0xc31a6620, addr=, len=3808, prot=3, flags=6146, pgoff=0) at mm/nommu.c:1373 #2 0xc00a96b8 in elf_fdpic_map_file (params=0xc33fbbec, file=0xc31a6620, mm=0xc31bef60, what=0xc0213144 "executable") at mm.h:1145 #3 0xc00aa8b4 in load_elf_fdpic_binary (bprm=0xc316cb00, regs=) at fs/binfmt_elf_fdpic.c:343 #4 0xc006b588 in search_binary_handler (bprm=0x6, regs=0xc33fbce0) at fs/exec.c:1234 #5 0xc006c648 in do_execve (filename=, argv=0xc3ad14cc, envp=0xc3ad1460, regs=0xc33fbce0) at fs/exec.c:1356 #6 0xc0008cf0 in sys_execve (name=, argv=0xc3ad14cc, envp=0xc3ad1460) at arch/frv/kernel/process.c:263 #7 0xc00075dc in __syscall_call () at arch/frv/kernel/entry.S:897 Note that this fix does the following commit differently: commit a190887b58c32d19c2eee007c5eb8faa970a69ba Author: David Howells Date: Sat Sep 5 11:17:07 2009 -0700 nommu: fix error handling in do_mmap_pgoff() Reported-by: Graff Yang Signed-off-by: David Howells Acked-by: Pekka Enberg Cc: Paul Mundt Cc: Mel Gorman Cc: Greg Ungerer Signed-off-by: Linus Torvalds --- mm/nommu.c | 34 ++++++++++++---------------------- 1 file changed, 12 insertions(+), 22 deletions(-) (limited to 'mm/nommu.c') diff --git a/mm/nommu.c b/mm/nommu.c index 56a446f0597..6a002abcb58 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -1034,7 +1034,7 @@ static int do_mmap_shared_file(struct vm_area_struct *vma) ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); if (ret == 0) { vma->vm_region->vm_top = vma->vm_region->vm_end; - return ret; + return 0; } if (ret != -ENOSYS) return ret; @@ -1051,7 +1051,8 @@ static int do_mmap_shared_file(struct vm_area_struct *vma) */ static int do_mmap_private(struct vm_area_struct *vma, struct vm_region *region, - unsigned long len) + unsigned long len, + unsigned long capabilities) { struct page *pages; unsigned long total, point, n, rlen; @@ -1062,13 +1063,13 @@ static int do_mmap_private(struct vm_area_struct *vma, * shared mappings on devices or memory * - VM_MAYSHARE will be set if it may attempt to share */ - if (vma->vm_file) { + if (capabilities & BDI_CAP_MAP_DIRECT) { ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); if (ret == 0) { /* shouldn't return success if we're not sharing */ BUG_ON(!(vma->vm_flags & VM_MAYSHARE)); vma->vm_region->vm_top = vma->vm_region->vm_end; - return ret; + return 0; } if (ret != -ENOSYS) return ret; @@ -1306,7 +1307,7 @@ unsigned long do_mmap_pgoff(struct file *file, * - this is the hook for quasi-memory character devices to * tell us the location of a shared mapping */ - if (file && file->f_op->get_unmapped_area) { + if (capabilities & BDI_CAP_MAP_DIRECT) { addr = file->f_op->get_unmapped_area(file, addr, len, pgoff, flags); if (IS_ERR((void *) addr)) { @@ -1330,15 +1331,17 @@ unsigned long do_mmap_pgoff(struct file *file, } vma->vm_region = region; - add_nommu_region(region); - /* set up the mapping */ + /* set up the mapping + * - the region is filled in if BDI_CAP_MAP_DIRECT is still set + */ if (file && vma->vm_flags & VM_SHARED) ret = do_mmap_shared_file(vma); else - ret = do_mmap_private(vma, region, len); + ret = do_mmap_private(vma, region, len, capabilities); if (ret < 0) - goto error_put_region; + goto error_just_free; + add_nommu_region(region); /* okay... we have a mapping; now we have to register it */ result = vma->vm_start; @@ -1356,19 +1359,6 @@ share: kleave(" = %lx", result); return result; -error_put_region: - __put_nommu_region(region); - if (vma) { - if (vma->vm_file) { - fput(vma->vm_file); - if (vma->vm_flags & VM_EXECUTABLE) - removed_exe_file_vma(vma->vm_mm); - } - kmem_cache_free(vm_area_cachep, vma); - } - kleave(" = %d [pr]", ret); - return ret; - error_just_free: up_write(&nommu_region_sem); error: -- cgit v1.2.3 From 06aab5a3084e1d825384fa353e6df4c7949c8683 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 24 Sep 2009 12:33:48 +0100 Subject: NOMMU: Ignore mmap() address param as it is a hint Ignore the address parameter given to NOMMU mmap() as it is a hint, rather than giving an error if it's non-zero. MAP_FIXED still gets an error. Signed-off-by: David Howells Signed-off-by: Linus Torvalds --- mm/nommu.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'mm/nommu.c') diff --git a/mm/nommu.c b/mm/nommu.c index 6a002abcb58..c73aa4753d7 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -826,7 +826,7 @@ static int validate_mmap_request(struct file *file, int ret; /* do the simple checks first */ - if (flags & MAP_FIXED || addr) { + if (flags & MAP_FIXED) { printk(KERN_DEBUG "%d: Can't do fixed-address/overlay mmap of RAM\n", current->pid); @@ -1182,9 +1182,6 @@ unsigned long do_mmap_pgoff(struct file *file, kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff); - if (!(flags & MAP_FIXED)) - addr = round_hint_to_min(addr); - /* decide whether we should attempt the mapping, and if so what sort of * mapping */ ret = validate_mmap_request(file, addr, len, prot, flags, pgoff, @@ -1194,6 +1191,9 @@ unsigned long do_mmap_pgoff(struct file *file, return ret; } + /* we ignore the address hint */ + addr = 0; + /* we've determined that we can make the mapping, now translate what we * now know into VMA flags */ vm_flags = determine_vm_flags(file, prot, flags, capabilities); -- cgit v1.2.3