linux-kernel - Re: Drivers: hv: vmbus: One function call less in create_gpadl

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Date: Wed, 10 Jan 2024 21:37:42 +0300
From: Dan Carpenter <dan.carpenter@...aro.org>
To: Michael Kelley <mhklinux@...look.com>
Cc: Markus Elfring <Markus.Elfring@....de>,
	"linux-hyperv@...r.kernel.org" <linux-hyperv@...r.kernel.org>,
	"kernel-janitors@...r.kernel.org" <kernel-janitors@...r.kernel.org>,
	Dexuan Cui <decui@...rosoft.com>,
	Haiyang Zhang <haiyangz@...rosoft.com>,
	"K. Y. Srinivasan" <kys@...rosoft.com>,
	Wei Liu <wei.liu@...nel.org>, "cocci@...ia.fr" <cocci@...ia.fr>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: Drivers: hv: vmbus: One function call less in
 create_gpadl_header() after error detection

The second half of the if statement is basically duplicated.  It doesn't
need to be treated as a special case.  We could do something like below.
I deliberately didn't delete the tabs.  Also I haven't tested it.

regards,
dan carpenter

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index 56f7e06c673e..2ba65f9ad3f1 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -328,9 +328,9 @@ static int create_gpadl_header(enum hv_gpadl_type type, void *kbuffer,
 		  sizeof(struct gpa_range);
 	pfncount = pfnsize / sizeof(u64);
 
-	if (pagecount > pfncount) {
-		/* we need a gpadl body */
-		/* fill in the header */
+	if (pagecount < pfncount)
+		pfncount = pagecount;
+
 		msgsize = sizeof(struct vmbus_channel_msginfo) +
 			  sizeof(struct vmbus_channel_gpadl_header) +
 			  sizeof(struct gpa_range) + pfncount * sizeof(u64);
@@ -410,31 +410,6 @@ static int create_gpadl_header(enum hv_gpadl_type type, void *kbuffer,
 			pfnsum += pfncurr;
 			pfnleft -= pfncurr;
 		}
-	} else {
-		/* everything fits in a header */
-		msgsize = sizeof(struct vmbus_channel_msginfo) +
-			  sizeof(struct vmbus_channel_gpadl_header) +
-			  sizeof(struct gpa_range) + pagecount * sizeof(u64);
-		msgheader = kzalloc(msgsize, GFP_KERNEL);
-		if (msgheader == NULL)
-			goto nomem;
-
-		INIT_LIST_HEAD(&msgheader->submsglist);
-		msgheader->msgsize = msgsize;
-
-		gpadl_header = (struct vmbus_channel_gpadl_header *)
-			msgheader->msg;
-		gpadl_header->rangecount = 1;
-		gpadl_header->range_buflen = sizeof(struct gpa_range) +
-					 pagecount * sizeof(u64);
-		gpadl_header->range[0].byte_offset = 0;
-		gpadl_header->range[0].byte_count = hv_gpadl_size(type, size);
-		for (i = 0; i < pagecount; i++)
-			gpadl_header->range[0].pfn_array[i] = hv_gpadl_hvpfn(
-				type, kbuffer, size, send_offset, i);
-
-		*msginfo = msgheader;
-	}
 
 	return 0;
 nomem: