The attached patch does two things:
(1) We no longer check the return value of file->f_op->get_unmapped_area()
unless we actually called it. We know addr is zero otherwise because
we'd've given an error earlier if it wasn't.
(2) If -ENOSYS was returned by that operation, then we assume we actually
called a driver (such as the framebuffer driver) that might want to
invoke the operation in a lower level driver (such as matroxfb) if one
exists, and that it found that one didn't.
We translate the -ENOSYS error into -ENODEV - the error we would have
given if the operation was not supplied in the file ops.
Doing this permits us an opportunity for arch_get_unmapped_area() or
something else to be called if we want that to happen, particularly in
the MMU case.
Signed-Off-By: David Howells <[EMAIL PROTECTED]>
---
warthog>diffstat -p1 nommu-2611rc3.diff
mm/nommu.c | 12 +++++++-----
1 files changed, 7 insertions(+), 5 deletions(-)
diff -uNrp /warthog/kernels/linux-2.6.11-rc3/mm/nommu.c
linux-2.6.11-rc3-frv/mm/nommu.c
--- /warthog/kernels/linux-2.6.11-rc3/mm/nommu.c 2005-02-04
11:50:28.000000000 +0000
+++ linux-2.6.11-rc3-frv/mm/nommu.c 2005-02-08 13:54:18.816577889 +0000
@@ -567,12 +567,14 @@ unsigned long do_mmap_pgoff(struct file
* that it represents a valid section of the address space
* - this is the hook for quasi-memory character devices
*/
- if (file && file->f_op->get_unmapped_area)
+ if (file && file->f_op->get_unmapped_area) {
addr = file->f_op->get_unmapped_area(file, addr, len, pgoff,
flags);
-
- if (IS_ERR((void *) addr)) {
- ret = addr;
- goto error;
+ if (IS_ERR((void *) addr)) {
+ ret = addr;
+ if (ret == (unsigned long) -ENOSYS)
+ ret = (unsigned long) -ENODEV;
+ goto error;
+ }
}
/* we're going to need a VMA struct as well */
-
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