[ndctl PATCH] util/sysfs: do not fail on missing bind attributes

[Alison Schofield <alison.schofield@intel.com>]

From: Tao Xu <xutao323@gmail.com>

Kernel commit cb9cfff82f6a ("cxl/acpi: Simplify cxl_nvdimm_bridge
probing") removed bind attrributes for cxl_pmem_region and
cxl_nvdimm* objects.

__util_bind() currently attempts to write to the bind attribute of
every entry under /sys/bus/cxl/drivers/. On kernels where some driver
directories no longer provide that attribute, these attempts fail with
ENOENT and produce misleading bind errors.

Check that the bind attribute exists before attempting the write.

[ as: commit log edited ]

Reported-by: Tao Xu <xutao323@gmail.com>
Closes: https://github.com/pmem/ndctl/issues/298
Signed-off-by: Tao Xu <xutao323@gmail.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Signed-off-by: Alison Schofield <alison.schofield@intel.com>
---
 util/sysfs.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/util/sysfs.c b/util/sysfs.c
index eaf4b60aacee..2dd4b48b4459 100644
--- a/util/sysfs.c
+++ b/util/sysfs.c
@@ -258,6 +258,11 @@ int __util_bind(const char *devname, struct kmod_module *module,
 			continue;
 		}
 
+		if (access(drv_path, F_OK) != 0) {
+			free(drv_path);
+			continue;
+		}
+
 		rc = __sysfs_write_attr_quiet(ctx, drv_path, devname);
 		free(drv_path);
 		if (rc == 0)
-- 
2.37.3