[PATCH 1/1] io_uring/zcrx: fix builds without dmabuf

[Pavel Begunkov <asml.silence@gmail.com>]

armv7a-unknown-linux-gnueabihf-ld: io_uring/zcrx.o: in function
`io_release_dmabuf':
zcrx.c:(.text+0x1c): undefined reference to `dma_buf_unmap_attachment_unlocked'
armv7a-unknown-linux-gnueabihf-ld: zcrx.c:(.text+0x30): undefined
reference to `dma_buf_detach'
armv7a-unknown-linux-gnueabihf-ld: zcrx.c:(.text+0x40): undefined
reference to `dma_buf_put'
armv7a-unknown-linux-gnueabihf-ld: io_uring/zcrx.o: in function
`io_register_zcrx_ifq':
zcrx.c:(.text+0x15cc): undefined reference to `dma_buf_get'
armv7a-unknown-linux-gnueabihf-ld: zcrx.c:(.text+0x15e8): undefined
reference to `dma_buf_attach'
armv7a-unknown-linux-gnueabihf-ld: zcrx.c:(.text+0x1604): undefined
reference to `dma_buf_map_attachment_unlocked'
make[2]: *** [scripts/Makefile.vmlinux:91: vmlinux] Error 1
make[1]: *** [/home/alchark/linux/Makefile:1242: vmlinux] Error 2
make: *** [Makefile:248: __sub-make] Error 2

There are no definitions for dma-buf functions without
CONFIG_DMA_SHARED_BUFFER, make sure we don't try to link to them
if dma-bufs are not enabled.

Reported-by: Alexey Charkov <alchark@gmail.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 io_uring/zcrx.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/io_uring/zcrx.c b/io_uring/zcrx.c
index fac293bcba72..9a568d049204 100644
--- a/io_uring/zcrx.c
+++ b/io_uring/zcrx.c
@@ -49,6 +49,9 @@ static inline struct page *io_zcrx_iov_page(const struct net_iov *niov)
 
 static void io_release_dmabuf(struct io_zcrx_mem *mem)
 {
+	if (!IS_ENABLED(CONFIG_DMA_SHARED_BUFFER))
+		return;
+
 	if (mem->sgt)
 		dma_buf_unmap_attachment_unlocked(mem->attach, mem->sgt,
 						  DMA_FROM_DEVICE);
@@ -75,6 +78,8 @@ static int io_import_dmabuf(struct io_zcrx_ifq *ifq,
 
 	if (WARN_ON_ONCE(!ifq->dev))
 		return -EFAULT;
+	if (!IS_ENABLED(CONFIG_DMA_SHARED_BUFFER))
+		return -EINVAL;
 
 	mem->is_dmabuf = true;
 	mem->dmabuf = dma_buf_get(dmabuf_fd);
@@ -118,6 +123,9 @@ static int io_zcrx_map_area_dmabuf(struct io_zcrx_ifq *ifq, struct io_zcrx_area
 	struct scatterlist *sg;
 	unsigned i, niov_idx = 0;
 
+	if (!IS_ENABLED(CONFIG_DMA_SHARED_BUFFER))
+		return -EINVAL;
+
 	for_each_sgtable_dma_sg(area->mem.sgt, sg, i) {
 		dma_addr_t dma = sg_dma_address(sg);
 		unsigned long sg_len = sg_dma_len(sg);
-- 
2.49.0