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Subject[PATCH] Reduce stack usage in time.c
Attempt to reduce stack usage in time.c (linux-2.6.12-rc1-mm3). Stack
usage was noted using checkstack.pl. Specifically:

Before patch
------------
sys_adjtimex - 128

After patch
-----------
sys_adjtimex - none (register usage only)

Signed-off-by: Yum Rayan <yum.rayan@gmail.com>

--- a/kernel/time.c 2005-03-25 22:11:06.000000000 -0800
+++ b/kernel/time.c 2005-03-30 16:59:51.000000000 -0800
@@ -413,17 +413,27 @@

asmlinkage long sys_adjtimex(struct timex __user *txc_p)
{
- struct timex txc; /* Local copy of parameter */
- int ret;
+ struct timex *txc; /* Local copy of parameter */
+ int retval;
+
+ txc = kmalloc(sizeof(struct timex), GFP_KERNEL);
+ if (!txc)
+ return -ENOMEM;

/* Copy the user data space into the kernel copy
* structure. But bear in mind that the structures
* may change
*/
- if(copy_from_user(&txc, txc_p, sizeof(struct timex)))
- return -EFAULT;
- ret = do_adjtimex(&txc);
- return copy_to_user(txc_p, &txc, sizeof(struct timex)) ? -EFAULT : ret;
+ if(copy_from_user(txc, txc_p, sizeof(struct timex))) {
+ retval = -EFAULT;
+ goto free_txc;
+ }
+ retval = do_adjtimex(txc);
+ if (copy_to_user(txc_p, txc, sizeof(struct timex)))
+ retval = -EFAULT;
+free_txc:
+ kfree(txc);
+ return retval;
}

inline struct timespec current_kernel_time(void)
-
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