X-Git-Url: https://git.karo-electronics.de/?a=blobdiff_plain;f=kernel%2Ffutex.c;h=470c06c3299a7feb5cc0598508715e453274c677;hb=2727c56c12b19283fd0eedf3271e2e30622b8ed9;hp=6e443efc65f41e8cd1d0bdf2d31afc63207390c1;hpb=38dab9ac1c017e96dc98e978111e365134d41d13;p=karo-tx-linux.git

diff --git a/kernel/futex.c b/kernel/futex.c
index 6e443efc65f4..470c06c3299a 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -255,9 +255,18 @@ struct futex_hash_bucket {
 	struct plist_head chain;
 } ____cacheline_aligned_in_smp;
 
-static unsigned long __read_mostly futex_hashsize;
+/*
+ * The base of the bucket array and its size are always used together
+ * (after initialization only in hash_futex()), so ensure that they
+ * reside in the same cacheline.
+ */
+static struct {
+	struct futex_hash_bucket *queues;
+	unsigned long            hashsize;
+} __futex_data __read_mostly __aligned(2*sizeof(long));
+#define futex_queues   (__futex_data.queues)
+#define futex_hashsize (__futex_data.hashsize)
 
-static struct futex_hash_bucket *futex_queues;
 
 /*
  * Fault injections for futexes.
@@ -267,10 +276,10 @@ static struct futex_hash_bucket *futex_queues;
 static struct {
 	struct fault_attr attr;
 
-	u32 ignore_private;
+	bool ignore_private;
 } fail_futex = {
 	.attr = FAULT_ATTR_INITIALIZER,
-	.ignore_private = 0,
+	.ignore_private = false,
 };
 
 static int __init setup_fail_futex(char *str)
@@ -460,7 +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, *page_head;
+	struct page *page;
 	int err, ro = 0;
 
 	/*
@@ -510,46 +519,9 @@ again:
 	else
 		err = 0;
 
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-	page_head = page;
-	if (unlikely(PageTail(page))) {
-		put_page(page);
-		/* serialize against __split_huge_page_splitting() */
-		local_irq_disable();
-		if (likely(__get_user_pages_fast(address, 1, !ro, &page) == 1)) {
-			page_head = compound_head(page);
-			/*
-			 * page_head is valid pointer but we must pin
-			 * it before taking the PG_lock and/or
-			 * PG_compound_lock. The moment we re-enable
-			 * irqs __split_huge_page_splitting() can
-			 * return and the head page can be freed from
-			 * under us. We can't take the PG_lock and/or
-			 * PG_compound_lock on a page that could be
-			 * freed from under us.
-			 */
-			if (page != page_head) {
-				get_page(page_head);
-				put_page(page);
-			}
-			local_irq_enable();
-		} else {
-			local_irq_enable();
-			goto again;
-		}
-	}
-#else
-	page_head = compound_head(page);
-	if (page != page_head) {
-		get_page(page_head);
-		put_page(page);
-	}
-#endif
-
-	lock_page(page_head);
-
+	lock_page(page);
 	/*
-	 * If page_head->mapping is NULL, then it cannot be a PageAnon
+	 * If page->mapping is NULL, then it cannot be a PageAnon
 	 * page; but it might be the ZERO_PAGE or in the gate area or
 	 * in a special mapping (all cases which we are happy to fail);
 	 * or it may have been a good file page when get_user_pages_fast
@@ -561,12 +533,12 @@ again:
 	 *
 	 * The case we do have to guard against is when memory pressure made
 	 * shmem_writepage move it from filecache to swapcache beneath us:
-	 * an unlikely race, but we do need to retry for page_head->mapping.
+	 * an unlikely race, but we do need to retry for page->mapping.
 	 */
-	if (!page_head->mapping) {
-		int shmem_swizzled = PageSwapCache(page_head);
-		unlock_page(page_head);
-		put_page(page_head);
+	if (!page->mapping) {
+		int shmem_swizzled = PageSwapCache(page);
+		unlock_page(page);
+		put_page(page);
 		if (shmem_swizzled)
 			goto again;
 		return -EFAULT;
@@ -579,7 +551,7 @@ again:
 	 * it's a read-only handle, it's expected that futexes attach to
 	 * the object not the particular process.
 	 */
-	if (PageAnon(page_head)) {
+	if (PageAnon(page)) {
 		/*
 		 * A RO anonymous page will never change and thus doesn't make
 		 * sense for futex operations.
@@ -594,15 +566,15 @@ again:
 		key->private.address = address;
 	} else {
 		key->both.offset |= FUT_OFF_INODE; /* inode-based key */
-		key->shared.inode = page_head->mapping->host;
+		key->shared.inode = page->mapping->host;
 		key->shared.pgoff = basepage_index(page);
 	}
 
 	get_futex_key_refs(key); /* implies MB (B) */
 
 out:
-	unlock_page(page_head);
-	put_page(page_head);
+	unlock_page(page);
+	put_page(page);
 	return err;
 }