[PATCH 09/14] USB speedtouch: use optimally sized reconstruction buffers

From: Duncan Sands (baldrick@wanadoo.fr)
Date: Tue May 20 2003 - 18:01:55 EST


Calculate the maximum size needed for the SAR
reconstruction buffer from the supplied qos parameters.

 speedtch.c | 12 +++++-------
 1 files changed, 5 insertions(+), 7 deletions(-)

diff -Nru a/drivers/usb/misc/speedtch.c b/drivers/usb/misc/speedtch.c
--- a/drivers/usb/misc/speedtch.c Wed May 21 00:40:46 2003
+++ b/drivers/usb/misc/speedtch.c Wed May 21 00:40:46 2003
@@ -107,9 +107,6 @@
 #define UDSL_NUM_SND_BUFS (2*UDSL_NUM_SND_URBS)
 #define UDSL_RCV_BUF_SIZE 64 /* ATM cells */
 #define UDSL_SND_BUF_SIZE 64 /* ATM cells */
-/* max should be (1500 IP mtu + 2 ppp bytes + 32 * 5 cellheader overhead) for
- * PPPoA and (1500 + 14 + 32*5 cellheader overhead) for PPPoE */
-#define UDSL_MAX_AAL5_MRU 2048
 
 #define UDSL_IOCTL_LINE_UP 1
 #define UDSL_IOCTL_LINE_DOWN 2
@@ -118,6 +115,7 @@
 #define UDSL_ENDPOINT_DATA_IN 0x87
 
 #define ATM_CELL_HEADER (ATM_CELL_SIZE - ATM_CELL_PAYLOAD)
+#define UDSL_NUM_CELLS(x) (((x) + ATM_AAL5_TRAILER + ATM_CELL_PAYLOAD - 1) / ATM_CELL_PAYLOAD)
 
 #define hex2int(c) ( (c >= '0') && (c <= '9') ? (c - '0') : ((c & 0xf) + 9) )
 
@@ -146,7 +144,7 @@
 
         /* raw cell reassembly */
         struct sk_buff *skb;
- unsigned short max_pdu;
+ unsigned int max_pdu;
 };
 
 /* send */
@@ -416,7 +414,7 @@
         ctrl->cell_header [3] = vcc->vci << 4;
         ctrl->cell_header [4] = 0xec;
 
- ctrl->num_cells = (skb->len + ATM_AAL5_TRAILER + ATM_CELL_PAYLOAD - 1) / ATM_CELL_PAYLOAD;
+ ctrl->num_cells = UDSL_NUM_CELLS (skb->len);
         ctrl->num_entire = skb->len / ATM_CELL_PAYLOAD;
 
         zero_padding = ctrl->num_cells * ATM_CELL_PAYLOAD - skb->len - ATM_AAL5_TRAILER;
@@ -921,7 +919,7 @@
                 return -EINVAL;
 
         /* only support AAL5 */
- if (vcc->qos.aal != ATM_AAL5)
+ if (vcc->qos.aal != ATM_AAL5 || vcc->qos.rxtp.max_sdu < 0 || vcc->qos.rxtp.max_sdu > ATM_MAX_AAL5_PDU)
                 return -EINVAL;
 
         if (!instance->firmware_loaded) {
@@ -945,7 +943,7 @@
         new->vcc = vcc;
         new->vpi = vpi;
         new->vci = vci;
- new->max_pdu = UDSL_MAX_AAL5_MRU;
+ new->max_pdu = max (1, UDSL_NUM_CELLS (vcc->qos.rxtp.max_sdu)) * ATM_CELL_PAYLOAD;
 
         vcc->dev_data = new;
         vcc->vpi = vpi;

-
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This archive was generated by hypermail 2b29 : Fri May 23 2003 - 22:00:42 EST