From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Carpenter Date: Wed, 27 Jun 2012 10:36:58 +0000 Subject: Re: [patch -resend] 9p: fix min_t() casting in p9pdu_vwritef() Message-Id: <20120627103658.GC3007@mwanda> List-Id: References: <20120627090141.GF31212@elgon.mountain> <4FEADE2E.90005@bfs.de> In-Reply-To: <4FEADE2E.90005@bfs.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: walter harms Cc: Eric Van Hensbergen , "David S. Miller" , "Aneesh Kumar K.V" , netdev@vger.kernel.org, kernel-janitors@vger.kernel.org On Wed, Jun 27, 2012 at 12:19:26PM +0200, walter harms wrote: > > > Am 27.06.2012 11:01, schrieb Dan Carpenter: > > I don't think we're actually likely to hit this limit but if we do > > then the comparison should be done as size_t. The original code > > is equivalent to: > > len = strlen(sptr) % USHRT_MAX; > > > > Signed-off-by: Dan Carpenter > > --- > > I was told this patch "has already made it upstream via the v9fs pull." > > but it must have been dropped accidentally. Originally sent on Sat, > > Jan 15, 2011. > > > > diff --git a/net/9p/protocol.c b/net/9p/protocol.c > > index 9ee48cb..3d33ecf 100644 > > --- a/net/9p/protocol.c > > +++ b/net/9p/protocol.c > > @@ -368,7 +368,7 @@ p9pdu_vwritef(struct p9_fcall *pdu, int proto_version, const char *fmt, > > const char *sptr = va_arg(ap, const char *); > > uint16_t len = 0; > > if (sptr) > > - len = min_t(uint16_t, strlen(sptr), > > + len = min_t(size_t, strlen(sptr), > > USHRT_MAX); > > > > errcode = p9pdu_writef(pdu, proto_version, > > this will result in > uint16_t = size_t > i would expect compilers to complains since uint16 < size_t > (most times). In this special case it seems more easy write it. > also ushort seems ambitious since uint16_t need not to be > ushort. so my idea would look like this: > > len=strlen > if (len>65535) lene535; > p9pdu_writef(...,(unint16_t)len); > No. I'm sorry, what you're saying is complete nonsense. The whole point of min_t() is that you can cast to both sides to what you want before you do the compare. Obviously I wouldn't submit a patch that introduces a compile warning. :/ regards, dan carpenter