powerpc/pseries: Remove kmalloc call in handling writes to lparcfg

There are only 4 valid name=value pairs for writes to
/proc/ppc64/lparcfg.  Current code allocates a buffer to copy
this information in from the user.  Since the longest name=value
pair will easily fit into a buffer of 64 characters, simply
put the buffer on the stack instead of allocating the buffer.

Signed-off-by: Nathan Fotenot <nfont@austin.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 12 insertions, 16 deletions

diff --git a/arch/powerpc/kernel/lparcfg.c b/arch/powerpc/kernel/lparcfg.c
index 64381a204a58..9f856a0c3e38 100644
--- a/arch/powerpc/kernel/lparcfg.c
+++ b/arch/powerpc/kernel/lparcfg.c
@@ -573,29 +573,27 @@ static ssize_t update_mpp(u64 *entitlement, u8 *weight)
 static ssize_t lparcfg_write(struct file *file, const char __user * buf,
                              size_t count, loff_t * off)
 {
-        char *kbuf;
+        int kbuf_sz = 64;
+        char kbuf[kbuf_sz];
         char *tmp;
         u64 new_entitled, *new_entitled_ptr = &new_entitled;
         u8 new_weight, *new_weight_ptr = &new_weight;
-        ssize_t retval = -ENOMEM;
+        ssize_t retval;
 
         if (!firmware_has_feature(FW_FEATURE_SPLPAR) ||
                         firmware_has_feature(FW_FEATURE_ISERIES))
                 return -EINVAL;
 
-        kbuf = kmalloc(count, GFP_KERNEL);
-        if (!kbuf)
-                goto out;
+        if (count > kbuf_sz)
+                return -EINVAL;
 
-        retval = -EFAULT;
         if (copy_from_user(kbuf, buf, count))
-                goto out;
+                return -EFAULT;
 
-        retval = -EINVAL;
         kbuf[count - 1] = '\0';
         tmp = strchr(kbuf, '=');
         if (!tmp)
-                goto out;
+                return -EINVAL;
 
         *tmp++ = '\0';
 
@@ -603,32 +601,32 @@ static ssize_t lparcfg_write(struct file *file, const char __user * buf,
                 char *endp;
                 *new_entitled_ptr = (u64) simple_strtoul(tmp, &endp, 10);
                 if (endp == tmp)
-                        goto out;
+                        return -EINVAL;
 
                 retval = update_ppp(new_entitled_ptr, NULL);
         } else if (!strcmp(kbuf, "capacity_weight")) {
                 char *endp;
                 *new_weight_ptr = (u8) simple_strtoul(tmp, &endp, 10);
                 if (endp == tmp)
-                        goto out;
+                        return -EINVAL;
 
                 retval = update_ppp(NULL, new_weight_ptr);
         } else if (!strcmp(kbuf, "entitled_memory")) {
                 char *endp;
                 *new_entitled_ptr = (u64) simple_strtoul(tmp, &endp, 10);
                 if (endp == tmp)
-                        goto out;
+                        return -EINVAL;
 
                 retval = update_mpp(new_entitled_ptr, NULL);
         } else if (!strcmp(kbuf, "entitled_memory_weight")) {
                 char *endp;
                 *new_weight_ptr = (u8) simple_strtoul(tmp, &endp, 10);
                 if (endp == tmp)
-                        goto out;
+                        return -EINVAL;
 
                 retval = update_mpp(NULL, new_weight_ptr);
         } else
-                goto out;
+                return -EINVAL;
 
         if (retval == H_SUCCESS || retval == H_CONSTRAINED) {
                 retval = count;
@@ -644,8 +642,6 @@ static ssize_t lparcfg_write(struct file *file, const char __user * buf,
                 retval = -EIO;
         }
 
-out:
-        kfree(kbuf);
         return retval;
 }