Backported special handling for nframes = 1 to reduce kmallocs in the common

use-case.

git-svn-id: svn://svn.berlios.de//socketcan/trunk@614 030b6a49-0b11-0410-94ab-b0dab22257f2

diff --git a/kernel/2.4/net/can/bcm.c b/kernel/2.4/net/can/bcm.c
index dcd1973d4645530881ef8e130d1a9974d9b15f84..487617d0a136a3b67c79d35803c0b0bbc3654f5a 100644 (file)
--- a/kernel/2.4/net/can/bcm.c
+++ b/kernel/2.4/net/can/bcm.c
@@ -97,6 +97,8 @@ struct bcm_op {
        int currframe;
        struct can_frame *frames;
        struct can_frame *last_frames;
+       struct can_frame sframe;
+       struct can_frame last_sframe;
        struct sock *sk;
 };
 
@@ -477,6 +479,7 @@ static void bcm_rx_cmp_to_index(struct bcm_op *op, int index,
        }
 
        /* do a real check in can_frame data section */
+
        if ((GET_U64(&op->frames[index]) & GET_U64(rxdata)) !=
            (GET_U64(&op->frames[index]) & GET_U64(&op->last_frames[index]))) {
                bcm_rx_update_and_send(op, &op->last_frames[index], rxdata);
@@ -485,7 +488,6 @@ static void bcm_rx_cmp_to_index(struct bcm_op *op, int index,
 
        if (op->flags & RX_CHECK_DLC) {
                /* do a real check in can_frame dlc */
-
                if (rxdata->can_dlc != (op->last_frames[index].can_dlc &
                                        BCM_CAN_DLC_MASK)) {
                        bcm_rx_update_and_send(op, &op->last_frames[index],
@@ -807,17 +809,22 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
                op->can_id    = msg_head->can_id;
 
                /* create array for can_frames and copy the data */
-               op->frames = kmalloc(msg_head->nframes * CFSIZ, GFP_KERNEL);
-               if(!op->frames) {
-                       kfree(op);
-                       return -ENOMEM;
-               }
+               if (msg_head->nframes > 1) {
+                       op->frames = kmalloc(msg_head->nframes * CFSIZ,
+                                            GFP_KERNEL);
+                       if (!op->frames) {
+                               kfree(op);
+                               return -ENOMEM;
+                       }
+               } else
+                       op->frames = &op->sframe;
 
                for (i = 0; i < msg_head->nframes; i++) {
-                       err = memcpy_fromiovec((u8*)&op->frames[i],
+                       err = memcpy_fromiovec((u8 *)&op->frames[i],
                                               msg->msg_iov, CFSIZ);
                        if (err < 0) {
-                               kfree(op->frames);
+                               if (op->frames != &op->sframe)
+                                       kfree(op->frames);
                                kfree(op);
                                return err;
                        }
@@ -932,7 +939,7 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
 
                if (msg_head->nframes) {
                        /* update can_frames content */
-                       err = memcpy_fromiovec((u8*)op->frames,
+                       err = memcpy_fromiovec((u8 *)op->frames,
                                               msg->msg_iov,
                                               msg_head->nframes * CFSIZ);
                        if (err < 0)
@@ -956,8 +963,7 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
                op->can_id    = msg_head->can_id;
                op->nframes   = msg_head->nframes;
 
-               if (msg_head->nframes) {
-
+               if (msg_head->nframes > 1) {
                        /* create array for can_frames and copy the data */
                        op->frames = kmalloc(msg_head->nframes * CFSIZ,
                                             GFP_KERNEL);
@@ -966,15 +972,7 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
                                return -ENOMEM;
                        }
 
-                       err = memcpy_fromiovec((u8*)op->frames, msg->msg_iov,
-                                              msg_head->nframes * CFSIZ);
-                       if (err < 0) {
-                               kfree(op->frames);
-                               kfree(op);
-                               return err;
-                       }
-
-                       /* create array for received can_frames */
+                       /* create and init array for received can_frames */
                        op->last_frames = kzalloc(msg_head->nframes * CFSIZ,
                                                  GFP_KERNEL);
                        if (!op->last_frames) {
@@ -984,16 +982,20 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
                        }
 
                } else {
-                       /* op->frames = NULL due to memset */
-
-                       /* even when we have the RX_FILTER_ID case, we need */
-                       /* to store the last frame for the throttle feature */
+                       op->frames = &op->sframe;
+                       op->last_frames = &op->last_sframe;
+               }
 
-                       /* create array for received can_frames */
-                       op->last_frames = kzalloc(CFSIZ, GFP_KERNEL);
-                       if (!op->last_frames) {
+               if (msg_head->nframes) {
+                       err = memcpy_fromiovec((u8 *)op->frames, msg->msg_iov,
+                                              msg_head->nframes * CFSIZ);
+                       if (err < 0) {
+                               if (op->frames != &op->sframe)
+                                       kfree(op->frames);
+                               if (op->last_frames != &op->last_sframe)
+                                       kfree(op->last_frames);
                                kfree(op);
-                               return -ENOMEM;
+                               return err;
                        }
                }