This is a note to let you know that I've just added the patch titled
IB/ipath: Convert ipath_user_sdma_pin_pages() to use get_user_pages_fast()
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ib-ipath-convert-ipath_user_sdma_pin_pages-to-use-get_user_pages_fast.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 4adcf7fb6783e354aab38824d803fa8c4f8e8a27 Mon Sep 17 00:00:00 2001
From: Jan Kara <[email protected]>
Date: Fri, 4 Oct 2013 09:29:06 -0400
Subject: IB/ipath: Convert ipath_user_sdma_pin_pages() to use
get_user_pages_fast()
From: Jan Kara <[email protected]>
commit 4adcf7fb6783e354aab38824d803fa8c4f8e8a27 upstream.
ipath_user_sdma_queue_pkts() gets called with mmap_sem held for
writing. Except for get_user_pages() deep down in
ipath_user_sdma_pin_pages() we don't seem to need mmap_sem at all.
Even more interestingly the function ipath_user_sdma_queue_pkts() (and
also ipath_user_sdma_coalesce() called somewhat later) call
copy_from_user() which can hit a page fault and we deadlock on trying
to get mmap_sem when handling that fault. So just make
ipath_user_sdma_pin_pages() use get_user_pages_fast() and leave
mmap_sem locking for mm.
This deadlock has actually been observed in the wild when the node
is under memory pressure.
Signed-off-by: Jan Kara <[email protected]>
Signed-off-by: Mike Marciniszyn <[email protected]>
[ Merged in fix for call to get_user_pages_fast from Tetsuo Handa
<[email protected]>. - Roland ]
Signed-off-by: Roland Dreier <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/infiniband/hw/ipath/ipath_user_sdma.c | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)
--- a/drivers/infiniband/hw/ipath/ipath_user_sdma.c
+++ b/drivers/infiniband/hw/ipath/ipath_user_sdma.c
@@ -280,9 +280,7 @@ static int ipath_user_sdma_pin_pages(con
int j;
int ret;
- ret = get_user_pages(current, current->mm, addr,
- npages, 0, 1, pages, NULL);
-
+ ret = get_user_pages_fast(addr, npages, 0, pages);
if (ret != npages) {
int i;
@@ -811,10 +809,7 @@ int ipath_user_sdma_writev(struct ipath_
while (dim) {
const int mxp = 8;
- down_write(¤t->mm->mmap_sem);
ret = ipath_user_sdma_queue_pkts(dd, pq, &list, iov, dim, mxp);
- up_write(¤t->mm->mmap_sem);
-
if (ret <= 0)
goto done_unlock;
else {
Patches currently in stable-queue which might be from [email protected] are
queue-3.10/ib-ipath-convert-ipath_user_sdma_pin_pages-to-use-get_user_pages_fast.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
