tty/sysrq: emergency_thaw_all does not depend on CONFIG_BLOCK

We can also thaw non-block file systems.  Remove the CONFIG_BLOCK in
sysrq.c after making the prototype available unconditionally.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/tty/sysrq.c

@@ -403,7 +403,6 @@ static const struct sysrq_key_op sysrq_moom_op = {
 	.enable_mask	= SYSRQ_ENABLE_SIGNAL,
 };
 
-#ifdef CONFIG_BLOCK
 static void sysrq_handle_thaw(int key)
 {
 	emergency_thaw_all();
@@ -414,7 +413,6 @@ static const struct sysrq_key_op sysrq_thaw_op = {
 	.action_msg	= "Emergency Thaw of all frozen filesystems",
 	.enable_mask	= SYSRQ_ENABLE_SIGNAL,
 };
-#endif
 
 static void sysrq_handle_kill(int key)
 {

include/linux/fs.h

@@ -2593,7 +2593,6 @@ extern void invalidate_bdev(struct block_device *);
 extern void iterate_bdevs(void (*)(struct block_device *, void *), void *);
 extern int sync_blockdev(struct block_device *bdev);
 extern struct super_block *freeze_bdev(struct block_device *);
-extern void emergency_thaw_all(void);
 extern void emergency_thaw_bdev(struct super_block *sb);
 extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
 extern int fsync_bdev(struct block_device *);
@@ -2633,6 +2632,7 @@ static inline bool sb_is_blkdev_sb(struct super_block *sb)
 	return false;
 }
 #endif
+void emergency_thaw_all(void);
 extern int sync_filesystem(struct super_block *);
 extern const struct file_operations def_blk_fops;
 extern const struct file_operations def_chr_fops;