Messages in this thread Patch in this message | | | Subject | [PATCH 1/2][RFC][BUG] msync: massive code cleanup of sys_msync() | From | Anton Salikhmetov <> | Date | Fri, 11 Jan 2008 03:38:42 +0300 |
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From: Anton Salikhmetov <salikhmetov@gmail.com>
The patch contains substantial code cleanup of the sys_msync() function:
1) consolidated error check for function parameters; 2) using the PAGE_ALIGN() macro instead of "manual" alignment; 3) improved readability of the loop traversing the process memory regions.
Signed-off-by: Anton Salikhmetov <salikhmetov@gmail.com>
---
diff --git a/mm/msync.c b/mm/msync.c index 144a757..e788f7b 100644 --- a/mm/msync.c +++ b/mm/msync.c @@ -1,24 +1,25 @@ /* * linux/mm/msync.c * + * The msync() system call. * Copyright (C) 1994-1999 Linus Torvalds + * + * Substantial code cleanup. + * Copyright (C) 2008 Anton Salikhmetov <salikhmetov@gmail.com> */ -/* - * The msync() system call. - */ +#include <linux/file.h> #include <linux/fs.h> #include <linux/mm.h> #include <linux/mman.h> -#include <linux/file.h> -#include <linux/syscalls.h> #include <linux/sched.h> +#include <linux/syscalls.h> /* * MS_SYNC syncs the entire file - including mappings. * * MS_ASYNC does not start I/O (it used to, up to 2.5.67). - * Nor does it marks the relevant pages dirty (it used to up to 2.6.17). + * Nor does it mark the relevant pages dirty (it used to up to 2.6.17). * Now it doesn't do anything, since dirty pages are properly tracked. * * The application may now run fsync() to @@ -33,71 +34,60 @@ asmlinkage long sys_msync(unsigned long start, size_t len, int flags) unsigned long end; struct mm_struct *mm = current->mm; struct vm_area_struct *vma; - int unmapped_error = 0; - int error = -EINVAL; + int error = 0, unmapped_error = 0; + + if ((flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC)) || + (start & ~PAGE_MASK) || + ((flags & MS_ASYNC) && (flags & MS_SYNC))) + return -EINVAL; - if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC)) - goto out; - if (start & ~PAGE_MASK) - goto out; - if ((flags & MS_ASYNC) && (flags & MS_SYNC)) - goto out; - error = -ENOMEM; - len = (len + ~PAGE_MASK) & PAGE_MASK; + len = PAGE_ALIGN(len); end = start + len; if (end < start) - goto out; - error = 0; + return -ENOMEM; if (end == start) - goto out; + return 0; + /* * If the interval [start,end) covers some unmapped address ranges, * just ignore them, but return -ENOMEM at the end. */ down_read(&mm->mmap_sem); vma = find_vma(mm, start); - for (;;) { + do { struct file *file; - /* Still start < end. */ - error = -ENOMEM; - if (!vma) - goto out_unlock; - /* Here start < vma->vm_end. */ + if (!vma) { + error = -ENOMEM; + break; + } if (start < vma->vm_start) { start = vma->vm_start; - if (start >= end) - goto out_unlock; + if (start >= end) { + error = -ENOMEM; + break; + } unmapped_error = -ENOMEM; } - /* Here vma->vm_start <= start < vma->vm_end. */ - if ((flags & MS_INVALIDATE) && - (vma->vm_flags & VM_LOCKED)) { + if ((flags & MS_INVALIDATE) && (vma->vm_flags & VM_LOCKED)) { error = -EBUSY; - goto out_unlock; + break; } file = vma->vm_file; - start = vma->vm_end; - if ((flags & MS_SYNC) && file && - (vma->vm_flags & VM_SHARED)) { + if ((flags & MS_SYNC) && file && (vma->vm_flags & VM_SHARED)) { get_file(file); up_read(&mm->mmap_sem); error = do_fsync(file, 0); fput(file); - if (error || start >= end) - goto out; + if (error) + return error; down_read(&mm->mmap_sem); - vma = find_vma(mm, start); - } else { - if (start >= end) { - error = 0; - goto out_unlock; - } - vma = vma->vm_next; } - } -out_unlock: + + start = vma->vm_end; + vma = vma->vm_next; + } while (start < end); up_read(&mm->mmap_sem); -out: + return error ? : unmapped_error; }
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