We patch DMA_BUF to make it tristate, so once ALL_KMODS is selected it will
be built as a module even if previously disabled in the config.
So, since IO_URING_ZCRX does not depend on DMA_BUF linking will fail with:
aarch64-openwrt-linux-musl-ld: Unexpected GOT/PLT entries detected!
aarch64-openwrt-linux-musl-ld: Unexpected run-time procedure linkages detected!
aarch64-openwrt-linux-musl-ld: io_uring/zcrx.o: in function `io_release_dmabuf':
io_uring/zcrx.c:94:(.text+0x20): undefined reference to `dma_buf_unmap_attachment_unlocked'
aarch64-openwrt-linux-musl-ld: io_uring/zcrx.c:97:(.text+0x30): undefined reference to `dma_buf_detach'
aarch64-openwrt-linux-musl-ld: io_uring/zcrx.c:99:(.text+0x3c): undefined reference to `dma_buf_put'
aarch64-openwrt-linux-musl-ld: io_uring/zcrx.o: in function `io_import_dmabuf':
io_uring/zcrx.c:125:(.text+0x1b20): undefined reference to `dma_buf_get'
aarch64-openwrt-linux-musl-ld: io_uring/zcrx.c:132:(.text+0x1b34): undefined reference to `dma_buf_attach'
aarch64-openwrt-linux-musl-ld: io_uring/zcrx.c:139:(.text+0x1b48): undefined reference to `dma_buf_map_attachment_unlocked'
make[6]: *** [scripts/Makefile.vmlinux:72: vmlinux.unstripped] Error 1
So, lets use IS_REACHABLE() to check for CONFIG_DMA_SHARED_BUFFER instead
to avoid adding a dependency to CONFIG_DMA_SHARED_BUFFER.
Signed-off-by: Robert Marko <robert.marko@sartura.hr>
