tree-wide: convert open calls to remove spaces to skip_spaces() lib function

Makes use of skip_spaces() defined in lib/string.c for removing leading
spaces from strings all over the tree.

It decreases lib.a code size by 47 bytes and reuses the function tree-wide:
   text    data     bss     dec     hex filename
  64688     584     592   65864   10148 (TOTALS-BEFORE)
  64641     584     592   65817   10119 (TOTALS-AFTER)

Also, while at it, if we see (*str && isspace(*str)), we can be sure to
remove the first condition (*str) as the second one (isspace(*str)) also
evaluates to 0 whenever *str == 0, making it redundant. In other words,
"a char equals zero is never a space".

Julia Lawall tried the semantic patch (http://coccinelle.lip6.fr) below,
and found occurrences of this pattern on 3 more files:
    drivers/leds/led-class.c
    drivers/leds/ledtrig-timer.c
    drivers/video/output.c

@@
expression str;
@@

( // ignore skip_spaces cases
while (*str &&  isspace(*str)) { \(str++;\|++str;\) }
|
- *str &&
isspace(*str)
)

Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Cc: Julia Lawall <julia@diku.dk>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Neil Brown <neilb@suse.de>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: David Howells <dhowells@redhat.com>
Cc: <linux-ext4@vger.kernel.org>
Cc: Samuel Ortiz <samuel@sortiz.org>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 13 insertions, 17 deletions

diff --git a/arch/s390/kernel/debug.c b/arch/s390/kernel/debug.c
index 071c81f179ef..0168472b2fdf 100644
--- a/arch/s390/kernel/debug.c
+++ b/arch/s390/kernel/debug.c
@@ -18,6 +18,7 @@
 #include <linux/errno.h>
 #include <linux/slab.h>
 #include <linux/ctype.h>
+#include <linux/string.h>
 #include <linux/sysctl.h>
 #include <asm/uaccess.h>
 #include <linux/module.h>
@@ -1178,7 +1179,7 @@ debug_get_uint(char *buf)
 {
         int rc;
 
-        for(; isspace(*buf); buf++);
+        buf = skip_spaces(buf);
         rc = simple_strtoul(buf, &buf, 10);
         if(*buf){
                 rc = -EINVAL;
diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c
index f0fa47f10e6c..51069245b79a 100644
--- a/arch/um/drivers/mconsole_kern.c
+++ b/arch/um/drivers/mconsole_kern.c
@@ -6,6 +6,7 @@
 
 #include <linux/console.h>
 #include <linux/ctype.h>
+#include <linux/string.h>
 #include <linux/interrupt.h>
 #include <linux/list.h>
 #include <linux/mm.h>
@@ -131,7 +132,7 @@ void mconsole_proc(struct mc_request *req)
         char *ptr = req->request.data, *buf;
 
         ptr += strlen("proc");
-        while (isspace(*ptr)) ptr++;
+        ptr = skip_spaces(ptr);
 
         proc = get_fs_type("proc");
         if (proc == NULL) {
@@ -212,8 +213,7 @@ void mconsole_proc(struct mc_request *req)
         char *ptr = req->request.data;
 
         ptr += strlen("proc");
-        while (isspace(*ptr))
-                ptr++;
+        ptr = skip_spaces(ptr);
         snprintf(path, sizeof(path), "/proc/%s", ptr);
 
         fd = sys_open(path, 0, 0);
@@ -560,8 +560,7 @@ void mconsole_config(struct mc_request *req)
         int err;
 
         ptr += strlen("config");
-        while (isspace(*ptr))
-                ptr++;
+        ptr = skip_spaces(ptr);
         dev = mconsole_find_dev(ptr);
         if (dev == NULL) {
                 mconsole_reply(req, "Bad configuration option", 1, 0);
@@ -588,7 +587,7 @@ void mconsole_remove(struct mc_request *req)
         int err, start, end, n;
 
         ptr += strlen("remove");
-        while (isspace(*ptr)) ptr++;
+        ptr = skip_spaces(ptr);
         dev = mconsole_find_dev(ptr);
         if (dev == NULL) {
                 mconsole_reply(req, "Bad remove option", 1, 0);
@@ -712,7 +711,7 @@ void mconsole_sysrq(struct mc_request *req)
         char *ptr = req->request.data;
 
         ptr += strlen("sysrq");
-        while (isspace(*ptr)) ptr++;
+        ptr = skip_spaces(ptr);
 
         /*
          * With 'b', the system will shut down without a chance to reply,
@@ -757,8 +756,7 @@ void mconsole_stack(struct mc_request *req)
          */
 
         ptr += strlen("stack");
-        while (isspace(*ptr))
-                ptr++;
+        ptr = skip_spaces(ptr);
 
         /*
          * Should really check for multiple pids or reject bad args here
diff --git a/arch/x86/kernel/cpu/mtrr/if.c b/arch/x86/kernel/cpu/mtrr/if.c
index 3c1b12d461d1..e006e56f699c 100644
--- a/arch/x86/kernel/cpu/mtrr/if.c
+++ b/arch/x86/kernel/cpu/mtrr/if.c
@@ -4,6 +4,7 @@
 #include <linux/proc_fs.h>
 #include <linux/module.h>
 #include <linux/ctype.h>
+#include <linux/string.h>
 #include <linux/init.h>
 
 #define LINE_SIZE 80
@@ -133,8 +134,7 @@ mtrr_write(struct file *file, const char __user *buf, size_t len, loff_t * ppos)
                 return -EINVAL;
 
         base = simple_strtoull(line + 5, &ptr, 0);
-        while (isspace(*ptr))
-                ptr++;
+        ptr = skip_spaces(ptr);
 
         if (strncmp(ptr, "size=", 5))
                 return -EINVAL;
@@ -142,14 +142,11 @@ mtrr_write(struct file *file, const char __user *buf, size_t len, loff_t * ppos)
         size = simple_strtoull(ptr + 5, &ptr, 0);
         if ((base & 0xfff) || (size & 0xfff))
                 return -EINVAL;
-        while (isspace(*ptr))
-                ptr++;
+        ptr = skip_spaces(ptr);
 
         if (strncmp(ptr, "type=", 5))
                 return -EINVAL;
-        ptr += 5;
-        while (isspace(*ptr))
-                ptr++;
+        ptr = skip_spaces(ptr + 5);
 
         for (i = 0; i < MTRR_NUM_TYPES; ++i) {
                 if (strcmp(ptr, mtrr_strings[i]))