From: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Date: Thu, 15 Aug 2019 15:13:55 +0300
Subject: xdp: xdp_umem: replace kmap on vmap for umem map
Patch-mainline: v5.4-rc1
Git-commit: 624676e788992e4da8de1fad93bfe51563a7f9a0
References: bsc#1154353

For 64-bit there is no reason to use vmap/vunmap, so use page_address
as it was initially. For 32 bits, in some apps, like in samples
xdpsock_user.c when number of pgs in use is quite big, the kmap
memory can be not enough, despite on this, kmap looks like is
deprecated in such cases as it can block and should be used rather
for dynamic mm.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 net/xdp/xdp_umem.c |   36 ++++++++++++++++++++++++++++++------
 1 file changed, 30 insertions(+), 6 deletions(-)

--- a/net/xdp/xdp_umem.c
+++ b/net/xdp/xdp_umem.c
@@ -14,7 +14,7 @@
 #include <linux/netdevice.h>
 #include <linux/rtnetlink.h>
 #include <linux/idr.h>
-#include <linux/highmem.h>
+#include <linux/vmalloc.h>
 
 #include "xdp_umem.h"
 #include "xsk_queue.h"
@@ -178,7 +178,30 @@ static void xdp_umem_unmap_pages(struct
 	unsigned int i;
 
 	for (i = 0; i < umem->npgs; i++)
-		kunmap(umem->pgs[i]);
+		if (PageHighMem(umem->pgs[i]))
+			vunmap(umem->pages[i].addr);
+}
+
+static int xdp_umem_map_pages(struct xdp_umem *umem)
+{
+	unsigned int i;
+	void *addr;
+
+	for (i = 0; i < umem->npgs; i++) {
+		if (PageHighMem(umem->pgs[i]))
+			addr = vmap(&umem->pgs[i], 1, VM_MAP, PAGE_KERNEL);
+		else
+			addr = page_address(umem->pgs[i]);
+
+		if (!addr) {
+			xdp_umem_unmap_pages(umem);
+			return -ENOMEM;
+		}
+
+		umem->pages[i].addr = addr;
+	}
+
+	return 0;
 }
 
 static void xdp_umem_unpin_pages(struct xdp_umem *umem)
@@ -320,7 +343,7 @@ static int xdp_umem_reg(struct xdp_umem
 	u32 chunk_size = mr->chunk_size, headroom = mr->headroom;
 	unsigned int chunks, chunks_per_page;
 	u64 addr = mr->addr, size = mr->len;
-	int size_chk, err, i;
+	int size_chk, err;
 
 	if (chunk_size < XDP_UMEM_MIN_CHUNK_SIZE || chunk_size > PAGE_SIZE) {
 		/* Strictly speaking we could support this, if:
@@ -386,10 +409,11 @@ static int xdp_umem_reg(struct xdp_umem
 		goto out_pin;
 	}
 
-	for (i = 0; i < umem->npgs; i++)
-		umem->pages[i].addr = kmap(umem->pgs[i]);
+	err = xdp_umem_map_pages(umem);
+	if (!err)
+		return 0;
 
-	return 0;
+	kfree(umem->pages);
 
 out_pin:
 	xdp_umem_unpin_pages(umem);