2020-03-07 02:12:36

by John Hubbard

[permalink] [raw]
Subject: [PATCH] mm/gup: fixup for ce35133be382 mm/gup: track FOLL_PIN pages

This is a fixup for the mmotm commit ce35133be382
("mm/gup: track FOLL_PIN pages").

Add kerneldoc comments for pin_user_pages*() routines, in order
to get rid of "make -W1" warnings when building mm/gup.o.

This just adds @param documentation of:
pin_user_pages()
pin_user_pages_fast()
pin_user_pages_remote()

The param documentation was stolen from other gup.c functions,
because it looks reasonable enough.

Reported-by: Matthew Wilcox <[email protected]>
Signed-off-by: John Hubbard <[email protected]>
---
mm/gup.c | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)

diff --git a/mm/gup.c b/mm/gup.c
index f589299b0d4a..54af3b290cb0 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2766,6 +2766,12 @@ EXPORT_SYMBOL_GPL(get_user_pages_fast);
/**
* pin_user_pages_fast() - pin user pages in memory without taking locks
*
+ * @start: starting user address
+ * @nr_pages: number of pages from start to pin
+ * @gup_flags: flags modifying pin behaviour
+ * @pages: array that receives pointers to the pages pinned.
+ * Should be at least nr_pages long.
+ *
* Nearly the same as get_user_pages_fast(), except that FOLL_PIN is set. See
* get_user_pages_fast() for documentation on the function arguments, because
* the arguments here are identical.
@@ -2791,6 +2797,21 @@ EXPORT_SYMBOL_GPL(pin_user_pages_fast);
/**
* pin_user_pages_remote() - pin pages of a remote process (task != current)
*
+ * @tsk: the task_struct to use for page fault accounting, or
+ * NULL if faults are not to be recorded.
+ * @mm: mm_struct of target mm
+ * @start: starting user address
+ * @nr_pages: number of pages from start to pin
+ * @gup_flags: flags modifying lookup behaviour
+ * @pages: array that receives pointers to the pages pinned.
+ * Should be at least nr_pages long. Or NULL, if caller
+ * only intends to ensure the pages are faulted in.
+ * @vmas: array of pointers to vmas corresponding to each page.
+ * Or NULL if the caller does not require them.
+ * @locked: pointer to lock flag indicating whether lock is held and
+ * subsequently whether VM_FAULT_RETRY functionality can be
+ * utilised. Lock must initially be held.
+ *
* Nearly the same as get_user_pages_remote(), except that FOLL_PIN is set. See
* get_user_pages_remote() for documentation on the function arguments, because
* the arguments here are identical.
@@ -2819,6 +2840,15 @@ EXPORT_SYMBOL(pin_user_pages_remote);
/**
* pin_user_pages() - pin user pages in memory for use by other devices
*
+ * @start: starting user address
+ * @nr_pages: number of pages from start to pin
+ * @gup_flags: flags modifying lookup behaviour
+ * @pages: array that receives pointers to the pages pinned.
+ * Should be at least nr_pages long. Or NULL, if caller
+ * only intends to ensure the pages are faulted in.
+ * @vmas: array of pointers to vmas corresponding to each page.
+ * Or NULL if the caller does not require them.
+ *
* Nearly the same as get_user_pages(), except that FOLL_TOUCH is not set, and
* FOLL_PIN is set.
*
--
2.25.1