[PATCH] bitmap: parse input from kernel and user buffers

lib/bitmap.c:bitmap_parse() is a library function that received as input a
user buffer.  This seemed to have originated from the way the write_proc
function of the /proc filesystem operates.

This has been reworked to not use kmalloc and eliminates a lot of
get_user() overhead by performing one access_ok before using __get_user().

We need to test if we are in kernel or user space (is_user) and access the
buffer differently.  We cannot use __get_user() to access kernel addresses
in all cases, for example in architectures with separate address space for
kernel and user.

This function will be useful for other uses as well; for example, taking
input for /sysfs instead of /proc, so it was changed to accept kernel
buffers.  We have this use for the Linux UWB project, as part as the
upcoming bandwidth allocator code.

Only a few routines used this function and they were changed too.

Signed-off-by: Reinette Chatre <reinette.chatre@linux.intel.com>
Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Joe Korty <joe.korty@ccur.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 2 insertions, 2 deletions

diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
index 607c7809ad01..9a352667007c 100644
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -57,7 +57,7 @@ static int irq_affinity_write_proc(struct file *file, const char __user *buffer,
         if (!irq_desc[irq].chip->set_affinity || no_irq_affinity)
                 return -EIO;
 
-        err = cpumask_parse(buffer, count, new_value);
+        err = cpumask_parse_user(buffer, count, new_value);
         if (err)
                 return err;
 
diff --git a/kernel/profile.c b/kernel/profile.c
index 857300a2afec..f940b462eec9 100644
--- a/kernel/profile.c
+++ b/kernel/profile.c
@@ -399,7 +399,7 @@ static int prof_cpu_mask_write_proc (struct file *file, const char __user *buffe
         unsigned long full_count = count, err;
         cpumask_t new_value;
 
-        err = cpumask_parse(buffer, count, new_value);
+        err = cpumask_parse_user(buffer, count, new_value);
         if (err)
                 return err;