[PATCH] Remove unnecessary kmalloc/kfree calls in mtdchar

[Thiago Galesi]

Josh

Thank you for your feedback! You're right, and both read and write had
the problem. It's probably better to kmalloc once but calculate len in
the old way. Hopefully I got it right this time.

Index: linux-2.6.16.2/drivers/mtd/mtdchar.c
===================================================================
--- linux-2.6.16.2.orig/drivers/mtd/mtdchar.c
+++ linux-2.6.16.2/drivers/mtd/mtdchar.c
@@ -170,16 +170,22 @@ static ssize_t mtd_read(struct file *fil

 	/* FIXME: Use kiovec in 2.5 to lock down the user's buffers
 	   and pass them directly to the MTD functions */
+
+	if (count > MAX_KMALLOC_SIZE)
+		kbuf=kmalloc(MAX_KMALLOC_SIZE, GFP_KERNEL);
+	else
+		kbuf=kmalloc(count, GFP_KERNEL);
+
+	if (!kbuf)
+		return -ENOMEM;
+
 	while (count) {
+
 		if (count > MAX_KMALLOC_SIZE)
 			len = MAX_KMALLOC_SIZE;
 		else
 			len = count;

-		kbuf=kmalloc(len,GFP_KERNEL);
-		if (!kbuf)
-			return -ENOMEM;
-
 		switch (MTD_MODE(file)) {
 		case MTD_MODE_OTP_FACT:
 			ret = mtd->read_fact_prot_reg(mtd, *ppos, len, &retlen, kbuf);
@@ -215,9 +221,9 @@ static ssize_t mtd_read(struct file *fil
 			return ret;
 		}

-		kfree(kbuf);
 	}

+	kfree(kbuf);
 	return total_retlen;
 } /* mtd_read */

@@ -241,18 +247,23 @@ static ssize_t mtd_write(struct file *fi
 	if (!count)
 		return 0;

+	if (count > MAX_KMALLOC_SIZE)
+		kbuf=kmalloc(MAX_KMALLOC_SIZE, GFP_KERNEL);
+	else
+		kbuf=kmalloc(count, GFP_KERNEL);
+
+	if (!kbuf) {
+		printk("kmalloc is null\n");
+		return -ENOMEM;
+	}
+
 	while (count) {
+
 		if (count > MAX_KMALLOC_SIZE)
 			len = MAX_KMALLOC_SIZE;
 		else
 			len = count;

-		kbuf=kmalloc(len,GFP_KERNEL);
-		if (!kbuf) {
-			printk("kmalloc is null\n");
-			return -ENOMEM;
-		}
-
 		if (copy_from_user(kbuf, buf, len)) {
 			kfree(kbuf);
 			return -EFAULT;
@@ -282,10 +293,9 @@ static ssize_t mtd_write(struct file *fi
 			kfree(kbuf);
 			return ret;
 		}
-
-		kfree(kbuf);
 	}

+	kfree(kbuf);
 	return total_retlen;
 } /* mtd_write */
-
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