/* &custom_page_walker - A custom page walk handler for walk_user_pages().
* vma: The vma we walk pages of.
* page: The page we found or an %ERR_PTR() value
* virt_addr: The virtual address we are at while walking.
* customdata: Anything you would like to pass additionally.
*
* Returns:
* Negative values -> ERRNO values.
* 0 -> continue page walking.
* 1 -> abort page walking.
*
* If this functions gets a page, for which %IS_ERR(@page) is true, than it
* should do it's cleanup of customdata and return -PTR_ERR(@page).
*
* This function is called with @vma->vm_mm->page_table_lock held,
* if IS_ERR(@vma) is not true.
*
* But if IS_ERR(@vma) is true, IS_ERR(@page) is also true, since if we have no
* vma, then we also have no user space page.
*
* If it returns a negative value, then the page_table_lock must be dropped
* by this function, if it is held.
*/
This locking is rather awkward. Why is it necessary, and can it
be simplified??
wrt the removal of the vmas arg to get_user_pages(): I assume this
was because none of the multipage callers were using it?
The patches would be easier to follow if things were sequenced a
little differently: lose the intermediate steps. Or just roll
the whole thing into a single patch, really. I don't think there
are any intermediate steps in this one?
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/