packet: Don't pass start and offset separately to packet_check_range()

Fundamentally what packet_check_range() does is to check whether a given
memory range is within the allowed / expected memory set aside for packets
from a particular pool.  That range could represent a whole packet (from
packet_add_do()) or part of a packet (from packet_get_do()), but it doesn't
really matter which.

However, we pass the start of the range as two parameters: @start which is
the start of the packet, and @offset which is the offset within the packet
of the range we're interested in.  We never use these separately, only as
(start + offset).  Simplify the interface of packet_check_range() and
vu_packet_check_range() to directly take the start of the relevant range.
This will allow some additional future improvements.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 4 insertions, 7 deletions

diff --git a/vu_common.c b/vu_common.c
index 48826b1..686a09b 100644
--- a/vu_common.c
+++ b/vu_common.c
@@ -26,14 +26,12 @@
  * vu_packet_check_range() - Check if a given memory zone is contained in
  * 			     a mapped guest memory region
  * @buf:	Array of the available memory regions
- * @offset:	Offset of data range in packet descriptor
+ * @ptr:	Start of desired data range
  * @size:	Length of desired data range
- * @start:	Start of the packet descriptor
  *
  * Return: 0 if the zone is in a mapped memory region, -1 otherwise
  */
-int vu_packet_check_range(void *buf, size_t offset, size_t len,
-			  const char *start)
+int vu_packet_check_range(void *buf, const char *ptr, size_t len)
 {
 	struct vu_dev_region *dev_region;
 
@@ -41,9 +39,8 @@ int vu_packet_check_range(void *buf, size_t offset, size_t len,
 		/* NOLINTNEXTLINE(performance-no-int-to-ptr) */
 		char *m = (char *)(uintptr_t)dev_region->mmap_addr;
 
-		if (m <= start &&
-		    start + offset + len <= m + dev_region->mmap_offset +
-					       dev_region->size)
+		if (m <= ptr &&
+		    ptr + len <= m + dev_region->mmap_offset + dev_region->size)
 			return 0;
 	}