RE: [PATCH 2/4] Drivers: hv: Support the newly introduced KVPmessages in the driver

[KY Srinivasan]

> -----Original Message-----
> From: Dan Carpenter [mailto:dan.carpenter@xxxxxxxxxx]
> Sent: Sunday, March 11, 2012 6:43 AM
> To: KY Srinivasan
> Cc: gregkh@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> devel@xxxxxxxxxxxxxxxxxxxxxx; virtualization@xxxxxxxxxxxxxx; ohering@xxxxxxxx;
> Alan Stern
> Subject: Re: [PATCH 2/4] Drivers: hv: Support the newly introduced KVP
> messages in the driver
> 
> On Sat, Mar 10, 2012 at 03:32:09PM -0800, K. Y. Srinivasan wrote:
> > +		switch (message->kvp_hdr.operation) {
> > +		case KVP_OP_SET:
> > +			switch (in_msg->body.kvp_set.data.value_type) {
> > +			case REG_SZ:
> > +				/*
> > +				 * The value is a string - utf16 encoding.
> > +				 */
> > +				message->body.kvp_set.data.value_size =
> > +				utf16s_to_utf8s(
> > +				(wchar_t *)
> > +				in_msg->body.kvp_set.data.value,
> > +				in_msg->body.kvp_set.data.value_size,
> > +				UTF16_LITTLE_ENDIAN,
> > +				message->body.kvp_set.data.value,
> > +				HV_KVP_EXCHANGE_MAX_VALUE_SIZE) + 1;
> > +				break;
> > +
> 
> This block of unreadable text is so nasty.
> 
> You could return directly if the msg = kmalloc() fails and pull
> everything in one indent level.  It's normally more readable to
> handle errors as soon as possible anyway.

True.

> 
> Probably that's not enough to make a difference and we'd need to
> introduce a new function.
> 
> Btw I don't know if utf16s_to_utf8s() counts the NUL char or not.
> It feels like maybe we could end up with ->value_size equal to
> HV_KVP_EXCHANGE_MAX_VALUE_SIZE + 1.

The MAX value is set to accommodate the maximum string that will ever
be handled including the string terminator. The function utf16s_to_utf8s()
returns the converted string length but the returned length does not 
include the string terminator (like strlen), hence the "+1".

Dan, I will see if there are other comments on these patches and will
accommodate your suggestion then. If there are no other comments,
would you mind if I addressed your comments here in a separate patch.  


Regards,

K. Y

> 
> regards,
> dan carpenter

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