mm, vmalloc: use __GFP_HIGHMEM implicitly

__vmalloc* allows users to provide gfp flags for the underlying
allocation.  This API is quite popular

  $ git grep "=[[:space:]]__vmalloc\|return[[:space:]]*__vmalloc" | wc -l
  77

The only problem is that many people are not aware that they really want
to give __GFP_HIGHMEM along with other flags because there is really no
reason to consume precious lowmemory on CONFIG_HIGHMEM systems for pages
which are mapped to the kernel vmalloc space.  About half of users don't
use this flag, though.  This signals that we make the API unnecessarily
too complex.

This patch simply uses __GFP_HIGHMEM implicitly when allocating pages to
be mapped to the vmalloc space.  Current users which add __GFP_HIGHMEM
are simplified and drop the flag.

Link: http://lkml.kernel.org/r/20170307141020.29107-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Cristopher Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

20 files changed, 31 insertions, 41 deletions

diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c
index c66c943..f1a7693 100644
--- a/arch/parisc/kernel/module.c
+++ b/arch/parisc/kernel/module.c
@@ -218,7 +218,7 @@ void *module_alloc(unsigned long size)
 	 * easier than trying to map the text, data, init_text and
 	 * init_data correctly */
 	return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END,
-				    GFP_KERNEL | __GFP_HIGHMEM,
+				    GFP_KERNEL,
 				    PAGE_KERNEL_RWX, 0, NUMA_NO_NODE,
 				    __builtin_return_address(0));
 }
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index 477ae80..f67bd32 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -85,7 +85,7 @@ void *module_alloc(unsigned long size)
 
 	p = __vmalloc_node_range(size, MODULE_ALIGN,
 				    MODULES_VADDR + get_module_load_offset(),
-				    MODULES_END, GFP_KERNEL | __GFP_HIGHMEM,
+				    MODULES_END, GFP_KERNEL,
 				    PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
 				    __builtin_return_address(0));
 	if (p && (kasan_module_alloc(p, size) < 0)) {
diff --git a/drivers/block/drbd/drbd_bitmap.c b/drivers/block/drbd/drbd_bitmap.c
index dece26f..a804a41 100644
--- a/drivers/block/drbd/drbd_bitmap.c
+++ b/drivers/block/drbd/drbd_bitmap.c
@@ -409,7 +409,7 @@ static struct page **bm_realloc_pages(struct drbd_bitmap *b, unsigned long want)
 	new_pages = kzalloc(bytes, GFP_NOIO | __GFP_NOWARN);
 	if (!new_pages) {
 		new_pages = __vmalloc(bytes,
-				GFP_NOIO | __GFP_HIGHMEM | __GFP_ZERO,
+				GFP_NOIO | __GFP_ZERO,
 				PAGE_KERNEL);
 		if (!new_pages)
 			return NULL;
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_dump.c b/drivers/gpu/drm/etnaviv/etnaviv_dump.c
index d019b5e..2d955d7 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_dump.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_dump.c
@@ -161,8 +161,8 @@ void etnaviv_core_dump(struct etnaviv_gpu *gpu)
 	file_size += sizeof(*iter.hdr) * n_obj;
 
 	/* Allocate the file in vmalloc memory, it's likely to be big */
-	iter.start = __vmalloc(file_size, GFP_KERNEL | __GFP_HIGHMEM |
-			       __GFP_NOWARN | __GFP_NORETRY, PAGE_KERNEL);
+	iter.start = __vmalloc(file_size, GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY,
+			       PAGE_KERNEL);
 	if (!iter.start) {
 		dev_warn(gpu->dev, "failed to allocate devcoredump file\n");
 		return;
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index c92c31b..5db11a4 100644
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -406,7 +406,7 @@ static void *alloc_buffer_data(struct dm_bufio_client *c, gfp_t gfp_mask,
 	if (gfp_mask & __GFP_NORETRY)
 		noio_flag = memalloc_noio_save();
 
-	ptr = __vmalloc(c->block_size, gfp_mask | __GFP_HIGHMEM, PAGE_KERNEL);
+	ptr = __vmalloc(c->block_size, gfp_mask, PAGE_KERNEL);
 
 	if (gfp_mask & __GFP_NORETRY)
 		memalloc_noio_restore(noio_flag);
diff --git a/fs/btrfs/free-space-tree.c b/fs/btrfs/free-space-tree.c
index dd7fb22..fc0bd84 100644
--- a/fs/btrfs/free-space-tree.c
+++ b/fs/btrfs/free-space-tree.c
@@ -167,8 +167,7 @@ static u8 *alloc_bitmap(u32 bitmap_size)
 	if (mem)
 		return mem;
 
-	return __vmalloc(bitmap_size, GFP_NOFS | __GFP_HIGHMEM | __GFP_ZERO,
-			 PAGE_KERNEL);
+	return __vmalloc(bitmap_size, GFP_NOFS | __GFP_ZERO, PAGE_KERNEL);
 }
 
 int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
diff --git a/fs/file.c b/fs/file.c
index ad6f094..1c2972e 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -42,7 +42,7 @@ static void *alloc_fdmem(size_t size)
 		if (data != NULL)
 			return data;
 	}
-	return __vmalloc(size, GFP_KERNEL_ACCOUNT | __GFP_HIGHMEM, PAGE_KERNEL);
+	return __vmalloc(size, GFP_KERNEL_ACCOUNT, PAGE_KERNEL);
 }
 
 static void __free_fdtable(struct fdtable *fdt)
diff --git a/fs/xfs/kmem.c b/fs/xfs/kmem.c
index 780fc89..393b684 100644
--- a/fs/xfs/kmem.c
+++ b/fs/xfs/kmem.c
@@ -67,7 +67,7 @@ kmem_zalloc_large(size_t size, xfs_km_flags_t flags)
 		nofs_flag = memalloc_nofs_save();
 
 	lflags = kmem_flags_convert(flags);
-	ptr = __vmalloc(size, lflags | __GFP_HIGHMEM | __GFP_ZERO, PAGE_KERNEL);
+	ptr = __vmalloc(size, lflags | __GFP_ZERO, PAGE_KERNEL);
 
 	if (flags & KM_NOFS)
 		memalloc_nofs_restore(nofs_flag);
diff --git a/include/drm/drm_mem_util.h b/include/drm/drm_mem_util.h
index 70d4e22..d0f6cf2 100644
--- a/include/drm/drm_mem_util.h
+++ b/include/drm/drm_mem_util.h
@@ -37,8 +37,7 @@ static __inline__ void *drm_calloc_large(size_t nmemb, size_t size)
 	if (size * nmemb <= PAGE_SIZE)
 	    return kcalloc(nmemb, size, GFP_KERNEL);
 
-	return __vmalloc(size * nmemb,
-			 GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, PAGE_KERNEL);
+	return vzalloc(size * nmemb);
 }
 
 /* Modeled after cairo's malloc_ab, it's like calloc but without the zeroing. */
@@ -50,8 +49,7 @@ static __inline__ void *drm_malloc_ab(size_t nmemb, size_t size)
 	if (size * nmemb <= PAGE_SIZE)
 	    return kmalloc(nmemb * size, GFP_KERNEL);
 
-	return __vmalloc(size * nmemb,
-			 GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
+	return vmalloc(size * nmemb);
 }
 
 static __inline__ void *drm_malloc_gfp(size_t nmemb, size_t size, gfp_t gfp)
@@ -69,8 +67,7 @@ static __inline__ void *drm_malloc_gfp(size_t nmemb, size_t size, gfp_t gfp)
 			return ptr;
 	}
 
-	return __vmalloc(size * nmemb,
-			 gfp | __GFP_HIGHMEM, PAGE_KERNEL);
+	return __vmalloc(size * nmemb, gfp, PAGE_KERNEL);
 }
 
 static __inline void drm_free_large(void *ptr)
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 6f81e0f..dedf367 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -76,8 +76,7 @@ void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, uns
 
 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
 {
-	gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
-			  gfp_extra_flags;
+	gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
 	struct bpf_prog_aux *aux;
 	struct bpf_prog *fp;
 
@@ -107,8 +106,7 @@ EXPORT_SYMBOL_GPL(bpf_prog_alloc);
 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
 				  gfp_t gfp_extra_flags)
 {
-	gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
-			  gfp_extra_flags;
+	gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
 	struct bpf_prog *fp;
 	u32 pages, delta;
 	int ret;
@@ -655,8 +653,7 @@ out:
 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other,
 					      gfp_t gfp_extra_flags)
 {
-	gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
-			  gfp_extra_flags;
+	gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
 	struct bpf_prog *fp;
 
 	fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags, PAGE_KERNEL);
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 13642c7..fd2411f 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -67,8 +67,7 @@ void *bpf_map_area_alloc(size_t size)
 			return area;
 	}
 
-	return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | flags,
-			 PAGE_KERNEL);
+	return __vmalloc(size, GFP_KERNEL | flags, PAGE_KERNEL);
 }
 
 void bpf_map_area_free(void *area)
diff --git a/kernel/fork.c b/kernel/fork.c
index 55e325f..08ba696 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -221,7 +221,7 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
 
 	stack = __vmalloc_node_range(THREAD_SIZE, THREAD_SIZE,
 				     VMALLOC_START, VMALLOC_END,
-				     THREADINFO_GFP | __GFP_HIGHMEM,
+				     THREADINFO_GFP,
 				     PAGE_KERNEL,
 				     0, node, __builtin_return_address(0));
 
diff --git a/kernel/groups.c b/kernel/groups.c
index 8dd7a61..d097276 100644
--- a/kernel/groups.c
+++ b/kernel/groups.c
@@ -18,7 +18,7 @@ struct group_info *groups_alloc(int gidsetsize)
 	len = sizeof(struct group_info) + sizeof(kgid_t) * gidsetsize;
 	gi = kmalloc(len, GFP_KERNEL_ACCOUNT|__GFP_NOWARN|__GFP_NORETRY);
 	if (!gi)
-		gi = __vmalloc(len, GFP_KERNEL_ACCOUNT|__GFP_HIGHMEM, PAGE_KERNEL);
+		gi = __vmalloc(len, GFP_KERNEL_ACCOUNT, PAGE_KERNEL);
 	if (!gi)
 		return NULL;
 
diff --git a/kernel/module.c b/kernel/module.c
index f37308b..2b316b9 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2864,7 +2864,7 @@ static int copy_module_from_user(const void __user *umod, unsigned long len,
 
 	/* Suck in entire file: we'll want most of it. */
 	info->hdr = __vmalloc(info->len,
-			GFP_KERNEL | __GFP_HIGHMEM | __GFP_NOWARN, PAGE_KERNEL);
+			GFP_KERNEL | __GFP_NOWARN, PAGE_KERNEL);
 	if (!info->hdr)
 		return -ENOMEM;
 
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
index 9348d27..b10da59 100644
--- a/mm/kasan/kasan.c
+++ b/mm/kasan/kasan.c
@@ -691,7 +691,7 @@ int kasan_module_alloc(void *addr, size_t size)
 
 	ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
 			shadow_start + shadow_size,
-			GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
+			GFP_KERNEL | __GFP_ZERO,
 			PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
 			__builtin_return_address(0));
 
diff --git a/mm/nommu.c b/mm/nommu.c
index a80411d..fc184f5 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -246,8 +246,7 @@ void *vmalloc_user(unsigned long size)
 {
 	void *ret;
 
-	ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
-			PAGE_KERNEL);
+	ret = __vmalloc(size, GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL);
 	if (ret) {
 		struct vm_area_struct *vma;
 
diff --git a/mm/util.c b/mm/util.c
index f4e590b..718154d 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -382,7 +382,7 @@ void *kvmalloc_node(size_t size, gfp_t flags, int node)
 	if (ret || size <= PAGE_SIZE)
 		return ret;
 
-	return __vmalloc_node_flags(size, node, flags | __GFP_HIGHMEM);
+	return __vmalloc_node_flags(size, node, flags);
 }
 EXPORT_SYMBOL(kvmalloc_node);
 
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 717b1e8..1dda6d8 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1655,7 +1655,7 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
 	struct page **pages;
 	unsigned int nr_pages, array_size, i;
 	const gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO;
-	const gfp_t alloc_mask = gfp_mask | __GFP_NOWARN;
+	const gfp_t alloc_mask = gfp_mask | __GFP_HIGHMEM | __GFP_NOWARN;
 
 	nr_pages = get_vm_area_size(area) >> PAGE_SHIFT;
 	array_size = (nr_pages * sizeof(struct page *));
@@ -1818,7 +1818,7 @@ EXPORT_SYMBOL(__vmalloc);
 void *vmalloc(unsigned long size)
 {
 	return __vmalloc_node_flags(size, NUMA_NO_NODE,
-				    GFP_KERNEL | __GFP_HIGHMEM);
+				    GFP_KERNEL);
 }
 EXPORT_SYMBOL(vmalloc);
 
@@ -1835,7 +1835,7 @@ EXPORT_SYMBOL(vmalloc);
 void *vzalloc(unsigned long size)
 {
 	return __vmalloc_node_flags(size, NUMA_NO_NODE,
-				GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
+				GFP_KERNEL | __GFP_ZERO);
 }
 EXPORT_SYMBOL(vzalloc);
 
@@ -1852,7 +1852,7 @@ void *vmalloc_user(unsigned long size)
 	void *ret;
 
 	ret = __vmalloc_node(size, SHMLBA,
-			     GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
+			     GFP_KERNEL | __GFP_ZERO,
 			     PAGE_KERNEL, NUMA_NO_NODE,
 			     __builtin_return_address(0));
 	if (ret) {
@@ -1876,7 +1876,7 @@ EXPORT_SYMBOL(vmalloc_user);
  */
 void *vmalloc_node(unsigned long size, int node)
 {
-	return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL,
+	return __vmalloc_node(size, 1, GFP_KERNEL, PAGE_KERNEL,
 					node, __builtin_return_address(0));
 }
 EXPORT_SYMBOL(vmalloc_node);
@@ -1896,7 +1896,7 @@ EXPORT_SYMBOL(vmalloc_node);
 void *vzalloc_node(unsigned long size, int node)
 {
 	return __vmalloc_node_flags(size, node,
-			 GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
+			 GFP_KERNEL | __GFP_ZERO);
 }
 EXPORT_SYMBOL(vzalloc_node);
 
@@ -1918,7 +1918,7 @@ EXPORT_SYMBOL(vzalloc_node);
 
 void *vmalloc_exec(unsigned long size)
 {
-	return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC,
+	return __vmalloc_node(size, 1, GFP_KERNEL, PAGE_KERNEL_EXEC,
 			      NUMA_NO_NODE, __builtin_return_address(0));
 }
 
diff --git a/net/ceph/ceph_common.c b/net/ceph/ceph_common.c
index 1085338..4eb773c 100644
--- a/net/ceph/ceph_common.c
+++ b/net/ceph/ceph_common.c
@@ -187,7 +187,7 @@ void *ceph_kvmalloc(size_t size, gfp_t flags)
 			return ptr;
 	}
 
-	return __vmalloc(size, flags | __GFP_HIGHMEM, PAGE_KERNEL);
+	return __vmalloc(size, flags, PAGE_KERNEL);
 }
 
 
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index 3d05846..8876b7d 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -998,8 +998,7 @@ struct xt_table_info *xt_alloc_table_info(unsigned int size)
 	if (sz <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER))
 		info = kmalloc(sz, GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY);
 	if (!info) {
-		info = __vmalloc(sz, GFP_KERNEL | __GFP_NOWARN |
-				     __GFP_NORETRY | __GFP_HIGHMEM,
+		info = __vmalloc(sz, GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY,
 				 PAGE_KERNEL);
 		if (!info)
 			return NULL;