zbd: Support finishing zones on Android

BLKFINISHZONE is missing from older versions of the Android NDK header
files. Hence, define BLKFINISHZONE if it has not been defined and detect
at runtime whether or not the kernel supports finishing zones.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>

oslib/linux-blkzoned.c

@@ -22,6 +22,9 @@
 #include "zbd_types.h"
 
 #include <linux/blkzoned.h>
+#ifndef BLKFINISHZONE
+#define BLKFINISHZONE _IOW(0x12, 136, struct blk_zone_range)
+#endif
 
 /*
  * If the uapi headers installed on the system lacks zone capacity support,
@@ -312,7 +315,6 @@ int blkzoned_reset_wp(struct thread_data *td, struct fio_file *f,
 int blkzoned_finish_zone(struct thread_data *td, struct fio_file *f,
 			 uint64_t offset, uint64_t length)
 {
-#ifdef BLKFINISHZONE
 	struct blk_zone_range zr = {
 		.sector         = offset >> 9,
 		.nr_sectors     = length >> 9,
@@ -327,21 +329,19 @@ int blkzoned_finish_zone(struct thread_data *td, struct fio_file *f,
 			return -errno;
 	}
 
-	if (ioctl(fd, BLKFINISHZONE, &zr) < 0)
+	if (ioctl(fd, BLKFINISHZONE, &zr) < 0) {
 		ret = -errno;
+		/*
+		 * Kernel versions older than 5.5 do not support BLKFINISHZONE
+		 * and return the ENOTTY error code. These old kernels only
+		 * support block devices that close zones automatically.
+		 */
+		if (ret == ENOTTY)
+			ret = 0;
+	}
 
 	if (f->fd < 0)
 		close(fd);
 
 	return ret;
-#else
-	/*
-	 * Kernel versions older than 5.5 does not support BLKFINISHZONE. These
-	 * old kernels assumed zones are closed automatically at max_open_zones
-	 * limit. Also they did not support max_active_zones limit. Then there
-	 * was no need to finish zones to avoid errors caused by max_open_zones
-	 * or max_active_zones. For those old versions, just do nothing.
-	 */
-	return 0;
-#endif
 }