mm: remove vmalloc_user_node_flags

Open code it in __bpf_map_area_alloc, which is the only caller.  Also
clean up __bpf_map_area_alloc to have a single vmalloc call with slightly
different flags instead of the current two different calls.

For this to compile for the nommu case add a __vmalloc_node_range stub to
nommu.c.

[akpm@linux-foundation.org: fix nommu.c build]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Link: http://lkml.kernel.org/r/20200414131348.444715-27-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/vmalloc.h

@@ -106,7 +106,6 @@ extern void *vzalloc(unsigned long size);
 extern void *vmalloc_user(unsigned long size);
 extern void *vmalloc_node(unsigned long size, int node);
 extern void *vzalloc_node(unsigned long size, int node);
-extern void *vmalloc_user_node_flags(unsigned long size, int node, gfp_t flags);
 extern void *vmalloc_exec(unsigned long size);
 extern void *vmalloc_32(unsigned long size);
 extern void *vmalloc_32_user(unsigned long size);

kernel/bpf/syscall.c

@@ -25,6 +25,7 @@
 #include <linux/nospec.h>
 #include <linux/audit.h>
 #include <uapi/linux/btf.h>
+#include <asm/pgtable.h>
 #include <linux/bpf_lsm.h>
 
 #define IS_FD_ARRAY(map) ((map)->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY || \
@@ -281,26 +282,29 @@ static void *__bpf_map_area_alloc(u64 size, int numa_node, bool mmapable)
 	 * __GFP_RETRY_MAYFAIL to avoid such situations.
 	 */
 
-	const gfp_t flags = __GFP_NOWARN | __GFP_ZERO;
+	const gfp_t gfp = __GFP_NOWARN | __GFP_ZERO;
+	unsigned int flags = 0;
+	unsigned long align = 1;
 	void *area;
 
 	if (size >= SIZE_MAX)
 		return NULL;
 
 	/* kmalloc()'ed memory can't be mmap()'ed */
-	if (!mmapable && size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {
-		area = kmalloc_node(size, GFP_USER | __GFP_NORETRY | flags,
+	if (mmapable) {
+		BUG_ON(!PAGE_ALIGNED(size));
+		align = SHMLBA;
+		flags = VM_USERMAP;
+	} else if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {
+		area = kmalloc_node(size, gfp | GFP_USER | __GFP_NORETRY,
 				    numa_node);
 		if (area != NULL)
 			return area;
 	}
-	if (mmapable) {
-		BUG_ON(!PAGE_ALIGNED(size));
-		return vmalloc_user_node_flags(size, numa_node, GFP_KERNEL |
-					       __GFP_RETRY_MAYFAIL | flags);
-	}
-	return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_RETRY_MAYFAIL | flags,
-			      numa_node, __builtin_return_address(0));
+
+	return __vmalloc_node_range(size, align, VMALLOC_START, VMALLOC_END,
+			gfp | GFP_KERNEL | __GFP_RETRY_MAYFAIL, PAGE_KERNEL,
+			flags, numa_node, __builtin_return_address(0));
 }
 
 void *bpf_map_area_alloc(u64 size, int numa_node)

mm/nommu.c

@@ -150,6 +150,14 @@ void *__vmalloc(unsigned long size, gfp_t gfp_mask)
 }
 EXPORT_SYMBOL(__vmalloc);
 
+void *__vmalloc_node_range(unsigned long size, unsigned long align,
+		unsigned long start, unsigned long end, gfp_t gfp_mask,
+		pgprot_t prot, unsigned long vm_flags, int node,
+		const void *caller)
+{
+	return __vmalloc(size, gfp_mask);
+}
+
 void *__vmalloc_node(unsigned long size, unsigned long align, gfp_t gfp_mask,
 		int node, const void *caller)
 {
@@ -180,12 +188,6 @@ void *vmalloc_user(unsigned long size)
 }
 EXPORT_SYMBOL(vmalloc_user);
 
-void *vmalloc_user_node_flags(unsigned long size, int node, gfp_t flags)
-{
-	return __vmalloc_user_flags(size, flags | __GFP_ZERO);
-}
-EXPORT_SYMBOL(vmalloc_user_node_flags);
-
 struct page *vmalloc_to_page(const void *addr)
 {
 	return virt_to_page(addr);

mm/vmalloc.c

@@ -2659,26 +2659,6 @@ void *vzalloc_node(unsigned long size, int node)
 }
 EXPORT_SYMBOL(vzalloc_node);
 
-/**
- * vmalloc_user_node_flags - allocate memory for userspace on a specific node
- * @size: allocation size
- * @node: numa node
- * @flags: flags for the page level allocator
- *
- * The resulting memory area is zeroed so it can be mapped to userspace
- * without leaking data.
- *
- * Return: pointer to the allocated memory or %NULL on error
- */
-void *vmalloc_user_node_flags(unsigned long size, int node, gfp_t flags)
-{
-	return __vmalloc_node_range(size, SHMLBA,  VMALLOC_START, VMALLOC_END,
-				    flags | __GFP_ZERO, PAGE_KERNEL,
-				    VM_USERMAP, node,
-				    __builtin_return_address(0));
-}
-EXPORT_SYMBOL(vmalloc_user_node_flags);
-
 /**
  * vmalloc_exec - allocate virtually contiguous, executable memory
  * @size:	  allocation size