target: writev() on single-element vector is pointless

... in other news:
	filp_open() can't return a struct file with NULL dentry
	filp_open() can't return a struct file negative dentry
	filp_close() of something that never had been in any descriptor
tables is pointless - fput() is all you need
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

drivers/target/target_core_alua.c

@@ -27,6 +27,7 @@
 #include <linux/spinlock.h>
 #include <linux/configfs.h>
 #include <linux/export.h>
+#include <linux/file.h>
 #include <scsi/scsi.h>
 #include <scsi/scsi_cmnd.h>
 #include <asm/unaligned.h>
@@ -715,36 +716,18 @@ static int core_alua_write_tpg_metadata(
 	unsigned char *md_buf,
 	u32 md_buf_len)
 {
-	mm_segment_t old_fs;
-	struct file *file;
-	struct iovec iov[1];
-	int flags = O_RDWR | O_CREAT | O_TRUNC, ret;
-
-	memset(iov, 0, sizeof(struct iovec));
+	struct file *file = filp_open(path, O_RDWR | O_CREAT | O_TRUNC, 0600);
+	int ret;
 
-	file = filp_open(path, flags, 0600);
-	if (IS_ERR(file) || !file || !file->f_dentry) {
-		pr_err("filp_open(%s) for ALUA metadata failed\n",
-			path);
+	if (IS_ERR(file)) {
+		pr_err("filp_open(%s) for ALUA metadata failed\n", path);
 		return -ENODEV;
 	}
-
-	iov[0].iov_base = &md_buf[0];
-	iov[0].iov_len = md_buf_len;
-
-	old_fs = get_fs();
-	set_fs(get_ds());
-	ret = vfs_writev(file, &iov[0], 1, &file->f_pos);
-	set_fs(old_fs);
-
-	if (ret < 0) {
+	ret = kernel_write(file, md_buf, md_buf_len, 0);
+	if (ret < 0)
 		pr_err("Error writing ALUA metadata file: %s\n", path);
-		filp_close(file, NULL);
-		return -EIO;
-	}
-	filp_close(file, NULL);
-
-	return 0;
+	fput(file);
+	return ret ? -EIO : 0;
 }
 
 /*

drivers/target/target_core_pr.c

@@ -27,6 +27,7 @@
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/list.h>
+#include <linux/file.h>
 #include <scsi/scsi.h>
 #include <scsi/scsi_cmnd.h>
 #include <asm/unaligned.h>
@@ -1957,13 +1958,10 @@ static int __core_scsi3_write_aptpl_to_file(
 {
 	struct t10_wwn *wwn = &dev->t10_wwn;
 	struct file *file;
-	struct iovec iov[1];
-	mm_segment_t old_fs;
 	int flags = O_RDWR | O_CREAT | O_TRUNC;
 	char path[512];
 	int ret;
 
-	memset(iov, 0, sizeof(struct iovec));
 	memset(path, 0, 512);
 
 	if (strlen(&wwn->unit_serial[0]) >= 512) {
@@ -1974,31 +1972,22 @@ static int __core_scsi3_write_aptpl_to_file(
 
 	snprintf(path, 512, "/var/target/pr/aptpl_%s", &wwn->unit_serial[0]);
 	file = filp_open(path, flags, 0600);
-	if (IS_ERR(file) || !file || !file->f_dentry) {
+	if (IS_ERR(file)) {
 		pr_err("filp_open(%s) for APTPL metadata"
 			" failed\n", path);
-		return IS_ERR(file) ? PTR_ERR(file) : -ENOENT;
+		return PTR_ERR(file);
 	}
 
-	iov[0].iov_base = &buf[0];
 	if (!pr_aptpl_buf_len)
-		iov[0].iov_len = (strlen(&buf[0]) + 1); /* Add extra for NULL */
-	else
-		iov[0].iov_len = pr_aptpl_buf_len;
+		pr_aptpl_buf_len = (strlen(&buf[0]) + 1); /* Add extra for NULL */
 
-	old_fs = get_fs();
-	set_fs(get_ds());
-	ret = vfs_writev(file, &iov[0], 1, &file->f_pos);
-	set_fs(old_fs);
+	ret = kernel_write(file, buf, pr_aptpl_buf_len, 0);
 
-	if (ret < 0) {
+	if (ret < 0)
 		pr_debug("Error writing APTPL metadata file: %s\n", path);
-		filp_close(file, NULL);
-		return -EIO;
-	}
-	filp_close(file, NULL);
+	fput(file);
 
-	return 0;
+	return ret ? -EIO : 0;
 }
 
 static int