madvise() does not always return -EBADF on non-file mapped area
RFC PATCH 1/1 madvise() does not always return -EBADF on non-file mapped area
hi,
I came across the following problem. The madvise() system call returns -EBADF for areas which does not map to files, only for *behaviour* request MADV_WILLNEED.
Is this the intended behaviour of madvise() ?
According to man pages, madvise returns :
EBADF - the map exists, but the area maps something that isn?t a file.
I have attached a patch which could resolve the issue.
[ There is already a bug reported in OSDL regarding this issue: Bug # 2995 ].
Signature · 5 lines
regards, Suzuki K P Linux Technology Centre IBM Software Labs
Patch to fix madvise() syscall to return -EBADF on non-file mapped regions.
Signed Off by: Suzuki K P <[email protected]>
madvise.c.new renamed from madvise.c +5 -3
@@ -62,9 +62,6 @@ static long madvise_willneed(struct vm_a { struct file *file = vma->vm_file; - if (!file) - return -EBADF; - start = ((start - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; if (end > vma->vm_end) end = vma->vm_end;
@@ -114,8 +111,12 @@ static long madvise_dontneed(struct vm_a static long madvise_vma(struct vm_area_struct * vma, unsigned long start, unsigned long end, int behavior) { + struct file* filp = vma->vm_file; long error = -EBADF; + if(!filp) + goto out; + switch (behavior) { case MADV_NORMAL: case MADV_SEQUENTIAL:
@@ -136,6 +137,7 @@ static long madvise_vma(struct vm_area_s break; } +out: return error; }