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authorOlof Johansson <olof@lixom.net>2016-06-18 22:59:07 -0700
committerOlof Johansson <olof@lixom.net>2016-06-18 22:59:07 -0700
commit8fd0976702f05042c776848819e5fd2a835f23c9 (patch)
tree8a87b0e33bf39adcc53b3ee4be61155dab86417b /kernel/futex.c
parent58935f24a996cb55595c29dd5303bd9b778c8b00 (diff)
parent8f50b8e57442d28e41bb736c173d8a2490549a82 (diff)
Merge tag 'gpmc-omap-fixes-for-v4.7' of https://github.com/rogerq/linux into fixes
OMAP-GPMC: Fixes for for v4.7-rc cycle: - Fix omap gpmc EXTRADELAY timing. The DT provided timings were wrongly used causing devices requiring extra delay timing to fail. * tag 'gpmc-omap-fixes-for-v4.7' of https://github.com/rogerq/linux: memory: omap-gpmc: Fix omap gpmc EXTRADELAY timing + Linux 4.7-rc3 Signed-off-by: Olof Johansson <olof@lixom.net>
Diffstat (limited to 'kernel/futex.c')
-rw-r--r--kernel/futex.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/kernel/futex.c b/kernel/futex.c
index ee25f5ba4aca..33664f70e2d2 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -469,7 +469,7 @@ get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key, int rw)
{
unsigned long address = (unsigned long)uaddr;
struct mm_struct *mm = current->mm;
- struct page *page;
+ struct page *page, *tail;
struct address_space *mapping;
int err, ro = 0;
@@ -530,7 +530,15 @@ again:
* considered here and page lock forces unnecessarily serialization
* From this point on, mapping will be re-verified if necessary and
* page lock will be acquired only if it is unavoidable
- */
+ *
+ * Mapping checks require the head page for any compound page so the
+ * head page and mapping is looked up now. For anonymous pages, it
+ * does not matter if the page splits in the future as the key is
+ * based on the address. For filesystem-backed pages, the tail is
+ * required as the index of the page determines the key. For
+ * base pages, there is no tail page and tail == page.
+ */
+ tail = page;
page = compound_head(page);
mapping = READ_ONCE(page->mapping);
@@ -654,7 +662,7 @@ again:
key->both.offset |= FUT_OFF_INODE; /* inode-based key */
key->shared.inode = inode;
- key->shared.pgoff = basepage_index(page);
+ key->shared.pgoff = basepage_index(tail);
rcu_read_unlock();
}