1 files changed, 49 insertions, 17 deletions

diff --git a/fs/xfs/kmem.c b/fs/xfs/kmem.c
index 9f32af534ce4..da031b93e182 100644
--- a/fs/xfs/kmem.c
+++ b/fs/xfs/kmem.c
@@ -30,30 +30,24 @@ kmem_alloc(size_t size, xfs_km_flags_t flags)
 	} while (1);
 }
 
-void *
-kmem_alloc_large(size_t size, xfs_km_flags_t flags)
+
+/*
+ * __vmalloc() will allocate data pages and auxillary structures (e.g.
+ * pagetables) with GFP_KERNEL, yet we may be under GFP_NOFS context here. Hence
+ * we need to tell memory reclaim that we are in such a context via
+ * PF_MEMALLOC_NOFS to prevent memory reclaim re-entering the filesystem here
+ * and potentially deadlocking.
+ */
+static void *
+__kmem_vmalloc(size_t size, xfs_km_flags_t flags)
 {
 	unsigned nofs_flag = 0;
 	void	*ptr;
-	gfp_t	lflags;
-
-	trace_kmem_alloc_large(size, flags, _RET_IP_);
-
-	ptr = kmem_alloc(size, flags | KM_MAYFAIL);
-	if (ptr)
-		return ptr;
+	gfp_t	lflags = kmem_flags_convert(flags);
 
-	/*
-	 * __vmalloc() will allocate data pages and auxillary structures (e.g.
-	 * pagetables) with GFP_KERNEL, yet we may be under GFP_NOFS context
-	 * here. Hence we need to tell memory reclaim that we are in such a
-	 * context via PF_MEMALLOC_NOFS to prevent memory reclaim re-entering
-	 * the filesystem here and potentially deadlocking.
-	 */
 	if (flags & KM_NOFS)
 		nofs_flag = memalloc_nofs_save();
 
-	lflags = kmem_flags_convert(flags);
 	ptr = __vmalloc(size, lflags, PAGE_KERNEL);
 
 	if (flags & KM_NOFS)
@@ -62,6 +56,44 @@ kmem_alloc_large(size_t size, xfs_km_flags_t flags)
 	return ptr;
 }
 
+/*
+ * Same as kmem_alloc_large, except we guarantee the buffer returned is aligned
+ * to the @align_mask. We only guarantee alignment up to page size, we'll clamp
+ * alignment at page size if it is larger. vmalloc always returns a PAGE_SIZE
+ * aligned region.
+ */
+void *
+kmem_alloc_io(size_t size, int align_mask, xfs_km_flags_t flags)
+{
+	void	*ptr;
+
+	trace_kmem_alloc_io(size, flags, _RET_IP_);
+
+	if (WARN_ON_ONCE(align_mask >= PAGE_SIZE))
+		align_mask = PAGE_SIZE - 1;
+
+	ptr = kmem_alloc(size, flags | KM_MAYFAIL);
+	if (ptr) {
+		if (!((uintptr_t)ptr & align_mask))
+			return ptr;
+		kfree(ptr);
+	}
+	return __kmem_vmalloc(size, flags);
+}
+
+void *
+kmem_alloc_large(size_t size, xfs_km_flags_t flags)
+{
+	void	*ptr;
+
+	trace_kmem_alloc_large(size, flags, _RET_IP_);
+
+	ptr = kmem_alloc(size, flags | KM_MAYFAIL);
+	if (ptr)
+		return ptr;
+	return __kmem_vmalloc(size, flags);
+}
+
 void *
 kmem_realloc(const void *old, size_t newsize, xfs_km_flags_t flags)
 {