tpm: don't bother with removal of files in directory we'll be removing

FWIW, there is a reliable indication of removal - ->i_nlink going to 0 ;-)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Author: Al Viro

drivers/char/tpm/eventlog/common.c

@@ -32,7 +32,7 @@ static int tpm_bios_measurements_open(struct inode *inode,
 	struct tpm_chip *chip;
 
 	inode_lock(inode);
-	if (!inode->i_private) {
+	if (!inode->i_nlink) {
 		inode_unlock(inode);
 		return -ENODEV;
 	}
@@ -105,7 +105,7 @@ static int tpm_read_log(struct tpm_chip *chip)
 void tpm_bios_log_setup(struct tpm_chip *chip)
 {
 	const char *name = dev_name(&chip->dev);
-	unsigned int cnt;
+	struct dentry *dentry;
 	int log_version;
 	int rc = 0;
 
@@ -117,14 +117,12 @@ void tpm_bios_log_setup(struct tpm_chip *chip)
 		return;
 	log_version = rc;
 
-	cnt = 0;
-	chip->bios_dir[cnt] = securityfs_create_dir(name, NULL);
+	chip->bios_dir = securityfs_create_dir(name, NULL);
 	/* NOTE: securityfs_create_dir can return ENODEV if securityfs is
 	 * compiled out. The caller should ignore the ENODEV return code.
 	 */
-	if (IS_ERR(chip->bios_dir[cnt]))
-		goto err;
-	cnt++;
+	if (IS_ERR(chip->bios_dir))
+		return;
 
 	chip->bin_log_seqops.chip = chip;
 	if (log_version == EFI_TCG2_EVENT_LOG_FORMAT_TCG_2)
@@ -135,57 +133,37 @@ void tpm_bios_log_setup(struct tpm_chip *chip)
 			&tpm1_binary_b_measurements_seqops;
 
 
-	chip->bios_dir[cnt] =
+	dentry =
 	    securityfs_create_file("binary_bios_measurements",
-				   0440, chip->bios_dir[0],
+				   0440, chip->bios_dir,
 				   (void *)&chip->bin_log_seqops,
 				   &tpm_bios_measurements_ops);
-	if (IS_ERR(chip->bios_dir[cnt]))
+	if (IS_ERR(dentry))
 		goto err;
-	cnt++;
 
 	if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) {
 
 		chip->ascii_log_seqops.chip = chip;
 		chip->ascii_log_seqops.seqops =
 			&tpm1_ascii_b_measurements_seqops;
 
-		chip->bios_dir[cnt] =
+		dentry =
 			securityfs_create_file("ascii_bios_measurements",
-					       0440, chip->bios_dir[0],
+					       0440, chip->bios_dir,
 					       (void *)&chip->ascii_log_seqops,
 					       &tpm_bios_measurements_ops);
-		if (IS_ERR(chip->bios_dir[cnt]))
+		if (IS_ERR(dentry))
 			goto err;
-		cnt++;
 	}
 
 	return;
 
 err:
-	chip->bios_dir[cnt] = NULL;
 	tpm_bios_log_teardown(chip);
 	return;
 }
 
 void tpm_bios_log_teardown(struct tpm_chip *chip)
 {
-	int i;
-	struct inode *inode;
-
-	/* securityfs_remove currently doesn't take care of handling sync
-	 * between removal and opening of pseudo files. To handle this, a
-	 * workaround is added by making i_private = NULL here during removal
-	 * and to check it during open(), both within inode_lock()/unlock().
-	 * This design ensures that open() either safely gets kref or fails.
-	 */
-	for (i = (TPM_NUM_EVENT_LOG_FILES - 1); i >= 0; i--) {
-		if (chip->bios_dir[i]) {
-			inode = d_inode(chip->bios_dir[i]);
-			inode_lock(inode);
-			inode->i_private = NULL;
-			inode_unlock(inode);
-			securityfs_remove(chip->bios_dir[i]);
-		}
-	}
+	securityfs_remove(chip->bios_dir);
 }

include/linux/tpm.h

@@ -182,7 +182,7 @@ struct tpm_chip {
 	unsigned long duration[TPM_NUM_DURATIONS]; /* jiffies */
 	bool duration_adjusted;
 
-	struct dentry *bios_dir[TPM_NUM_EVENT_LOG_FILES];
+	struct dentry *bios_dir;
 
 	const struct attribute_group *groups[3 + TPM_MAX_HASHES];
 	unsigned int groups_cnt;