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Commit 16c14b46 authored by Nathan Fontenot's avatar Nathan Fontenot Committed by Benjamin Herrenschmidt
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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: default avatarNathan Fotenot <nfont@austin.ibm.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 8391e42a

arch/powerpc/kernel/lparcfg.c

+12 −16
Original line number Original line Diff line number Diff line
@@ -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,

static ssize_t lparcfg_write(struct file *file, const char __user * buf,

			     size_t count, loff_t * off)

			     size_t count, loff_t * off)

{

{

	char *kbuf;

	int kbuf_sz = 64;

	char kbuf[kbuf_sz];

	char *tmp;

	char *tmp;

	u64 new_entitled, *new_entitled_ptr = &new_entitled;

	u64 new_entitled, *new_entitled_ptr = &new_entitled;

	u8 new_weight, *new_weight_ptr = &new_weight;

	u8 new_weight, *new_weight_ptr = &new_weight;

	ssize_t retval = -ENOMEM;

	ssize_t retval;





	if (!firmware_has_feature(FW_FEATURE_SPLPAR) ||

	if (!firmware_has_feature(FW_FEATURE_SPLPAR) ||

			firmware_has_feature(FW_FEATURE_ISERIES))

			firmware_has_feature(FW_FEATURE_ISERIES))

		return -EINVAL;

		return -EINVAL;





	kbuf = kmalloc(count, GFP_KERNEL);

	if (count > kbuf_sz)

	if (!kbuf)

		return -EINVAL;

		goto out;





	retval = -EFAULT;

	if (copy_from_user(kbuf, buf, count))

	if (copy_from_user(kbuf, buf, count))

		goto out;

		return -EFAULT;





	retval = -EINVAL;

	kbuf[count - 1] = '\0';

	kbuf[count - 1] = '\0';

	tmp = strchr(kbuf, '=');

	tmp = strchr(kbuf, '=');

	if (!tmp)

	if (!tmp)

		goto out;

		return -EINVAL;





	*tmp++ = '\0';

	*tmp++ = '\0';
@@ -603,32 +601,32 @@ static ssize_t lparcfg_write(struct file *file, const char __user * buf, 
		char *endp;

		char *endp;

		*new_entitled_ptr = (u64) simple_strtoul(tmp, &endp, 10);

		*new_entitled_ptr = (u64) simple_strtoul(tmp, &endp, 10);

		if (endp == tmp)

		if (endp == tmp)

			goto out;

			return -EINVAL;





		retval = update_ppp(new_entitled_ptr, NULL);

		retval = update_ppp(new_entitled_ptr, NULL);

	} else if (!strcmp(kbuf, "capacity_weight")) {

	} else if (!strcmp(kbuf, "capacity_weight")) {

		char *endp;

		char *endp;

		*new_weight_ptr = (u8) simple_strtoul(tmp, &endp, 10);

		*new_weight_ptr = (u8) simple_strtoul(tmp, &endp, 10);

		if (endp == tmp)

		if (endp == tmp)

			goto out;

			return -EINVAL;





		retval = update_ppp(NULL, new_weight_ptr);

		retval = update_ppp(NULL, new_weight_ptr);

	} else if (!strcmp(kbuf, "entitled_memory")) {

	} else if (!strcmp(kbuf, "entitled_memory")) {

		char *endp;

		char *endp;

		*new_entitled_ptr = (u64) simple_strtoul(tmp, &endp, 10);

		*new_entitled_ptr = (u64) simple_strtoul(tmp, &endp, 10);

		if (endp == tmp)

		if (endp == tmp)

			goto out;

			return -EINVAL;





		retval = update_mpp(new_entitled_ptr, NULL);

		retval = update_mpp(new_entitled_ptr, NULL);

	} else if (!strcmp(kbuf, "entitled_memory_weight")) {

	} else if (!strcmp(kbuf, "entitled_memory_weight")) {

		char *endp;

		char *endp;

		*new_weight_ptr = (u8) simple_strtoul(tmp, &endp, 10);

		*new_weight_ptr = (u8) simple_strtoul(tmp, &endp, 10);

		if (endp == tmp)

		if (endp == tmp)

			goto out;

			return -EINVAL;





		retval = update_mpp(NULL, new_weight_ptr);

		retval = update_mpp(NULL, new_weight_ptr);

	} else

	} else

		goto out;

		return -EINVAL;





	if (retval == H_SUCCESS || retval == H_CONSTRAINED) {

	if (retval == H_SUCCESS || retval == H_CONSTRAINED) {

		retval = count;

		retval = count;
@@ -644,8 +642,6 @@ static ssize_t lparcfg_write(struct file *file, const char __user * buf, 
		retval = -EIO;

		retval = -EIO;

	}

	}





out:

	kfree(kbuf);

	return retval;

	return retval;

}

}