[PATCH] uml: return hotplug errors to host

I noticed that errors happening while hotplugging devices from the host were
never returned back to the mconsole client.  In some cases, success was
returned instead of even an information-free error.

This patch cleans that up by having the low-level configuration code pass back
an error string along with an error code.  At the top level, which knows
whether it is early boot time or responding to an mconsole request, the string
is printk'd or returned to the mconsole client.

There are also whitespace and trivial code cleanups in the surrounding code.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 8 insertions, 17 deletions

diff --git a/arch/um/include/chan_kern.h b/arch/um/include/chan_kern.h
index 9003a343e14..2d9aa7ef4c2 100644
--- a/arch/um/include/chan_kern.h
+++ b/arch/um/include/chan_kern.h
@@ -30,7 +30,7 @@ struct chan {
 extern void chan_interrupt(struct list_head *chans, struct delayed_work *task,
 			   struct tty_struct *tty, int irq);
 extern int parse_chan_pair(char *str, struct line *line, int device,
-			   const struct chan_opts *opts);
+			   const struct chan_opts *opts, char **error_out);
 extern int open_chan(struct list_head *chans);
 extern int write_chan(struct list_head *chans, const char *buf, int len,
 			     int write_irq);
diff --git a/arch/um/include/line.h b/arch/um/include/line.h
index b79643eeee0..a2486b4cc9f 100644
--- a/arch/um/include/line.h
+++ b/arch/um/include/line.h
@@ -76,7 +76,7 @@ struct lines {
 extern void line_close(struct tty_struct *tty, struct file * filp);
 extern int line_open(struct line *lines, struct tty_struct *tty);
 extern int line_setup(struct line *lines, unsigned int sizeof_lines,
-		      char *init);
+		      char *init, char **error_out);
 extern int line_write(struct tty_struct *tty, const unsigned char *buf,
 		      int len);
 extern void line_put_char(struct tty_struct *tty, unsigned char ch);
@@ -102,9 +102,11 @@ extern void lines_init(struct line *lines, int nlines, struct chan_opts *opts);
 extern void close_lines(struct line *lines, int nlines);
 
 extern int line_config(struct line *lines, unsigned int sizeof_lines,
-		       char *str, const struct chan_opts *opts);
+		       char *str, const struct chan_opts *opts,
+		       char **error_out);
 extern int line_id(char **str, int *start_out, int *end_out);
-extern int line_remove(struct line *lines, unsigned int sizeof_lines, int n);
+extern int line_remove(struct line *lines, unsigned int sizeof_lines, int n,
+		       char **error_out);
 extern int line_get_config(char *dev, struct line *lines,
 			   unsigned int sizeof_lines, char *str,
 			   int size, char **error_out);
diff --git a/arch/um/include/mconsole_kern.h b/arch/um/include/mconsole_kern.h
index 1ea6d928e1c..73030e52b2c 100644
--- a/arch/um/include/mconsole_kern.h
+++ b/arch/um/include/mconsole_kern.h
@@ -18,10 +18,10 @@ struct mconsole_entry {
 struct mc_device {
 	struct list_head list;
 	char *name;
-	int (*config)(char *);
+	int (*config)(char *, char **);
 	int (*get_config)(char *, char *, int, char **);
         int (*id)(char **, int *, int *);
-	int (*remove)(int);
+	int (*remove)(int, char **);
 };
 
 #define CONFIG_CHUNK(str, size, current, chunk, end) \
@@ -50,14 +50,3 @@ static inline void mconsole_register_dev(struct mc_device *new)
 #endif
 
 #endif
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */