1 files changed, 365 insertions, 209 deletions

diff --git a/drivers/usb/atm/usbatm.c b/drivers/usb/atm/usbatm.c
index 7af1883d4bf9..c1211fc037d9 100644
--- a/drivers/usb/atm/usbatm.c
+++ b/drivers/usb/atm/usbatm.c
@@ -72,6 +72,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
+#include <linux/netdevice.h>
 #include <linux/proc_fs.h>
 #include <linux/sched.h>
 #include <linux/signal.h>
@@ -91,19 +92,18 @@ static int usbatm_print_packet(const unsigned char *data, int len);
 #endif
 
 #define DRIVER_AUTHOR   "Johan Verrept, Duncan Sands <duncan.sands@free.fr>"
-#define DRIVER_VERSION  "1.9"
+#define DRIVER_VERSION  "1.10"
 #define DRIVER_DESC     "Generic USB ATM/DSL I/O, version " DRIVER_VERSION
 
 static const char usbatm_driver_name[] = "usbatm";
 
 #define UDSL_MAX_RCV_URBS               16
 #define UDSL_MAX_SND_URBS               16
-#define UDSL_MAX_RCV_BUF_SIZE           1024    /* ATM cells */
-#define UDSL_MAX_SND_BUF_SIZE           1024    /* ATM cells */
+#define UDSL_MAX_BUF_SIZE               64 * 1024       /* bytes */
 #define UDSL_DEFAULT_RCV_URBS           4
 #define UDSL_DEFAULT_SND_URBS           4
-#define UDSL_DEFAULT_RCV_BUF_SIZE       64      /* ATM cells */
-#define UDSL_DEFAULT_SND_BUF_SIZE       64      /* ATM cells */
+#define UDSL_DEFAULT_RCV_BUF_SIZE       64 * ATM_CELL_SIZE      /* bytes */
+#define UDSL_DEFAULT_SND_BUF_SIZE       64 * ATM_CELL_SIZE      /* bytes */
 
 #define ATM_CELL_HEADER                 (ATM_CELL_SIZE - ATM_CELL_PAYLOAD)
 
@@ -111,8 +111,8 @@ static const char usbatm_driver_name[] = "usbatm";
 
 static unsigned int num_rcv_urbs = UDSL_DEFAULT_RCV_URBS;
 static unsigned int num_snd_urbs = UDSL_DEFAULT_SND_URBS;
-static unsigned int rcv_buf_size = UDSL_DEFAULT_RCV_BUF_SIZE;
-static unsigned int snd_buf_size = UDSL_DEFAULT_SND_BUF_SIZE;
+static unsigned int rcv_buf_bytes = UDSL_DEFAULT_RCV_BUF_SIZE;
+static unsigned int snd_buf_bytes = UDSL_DEFAULT_SND_BUF_SIZE;
 
 module_param(num_rcv_urbs, uint, S_IRUGO);
 MODULE_PARM_DESC(num_rcv_urbs,
@@ -126,15 +126,15 @@ MODULE_PARM_DESC(num_snd_urbs,
                  __MODULE_STRING(UDSL_MAX_SND_URBS) ", default: "
                  __MODULE_STRING(UDSL_DEFAULT_SND_URBS) ")");
 
-module_param(rcv_buf_size, uint, S_IRUGO);
-MODULE_PARM_DESC(rcv_buf_size,
-                 "Size of the buffers used for reception in ATM cells (range: 1-"
-                 __MODULE_STRING(UDSL_MAX_RCV_BUF_SIZE) ", default: "
+module_param(rcv_buf_bytes, uint, S_IRUGO);
+MODULE_PARM_DESC(rcv_buf_bytes,
+                 "Size of the buffers used for reception, in bytes (range: 1-"
+                 __MODULE_STRING(UDSL_MAX_BUF_SIZE) ", default: "
                  __MODULE_STRING(UDSL_DEFAULT_RCV_BUF_SIZE) ")");
 
-module_param(snd_buf_size, uint, S_IRUGO);
-MODULE_PARM_DESC(snd_buf_size,
-                 "Size of the buffers used for transmission in ATM cells (range: 1-"
+module_param(snd_buf_bytes, uint, S_IRUGO);
+MODULE_PARM_DESC(snd_buf_bytes,
+                 "Size of the buffers used for transmission, in bytes (range: 1-"
                  __MODULE_STRING(UDSL_MAX_SND_BUF_SIZE) ", default: "
                  __MODULE_STRING(UDSL_DEFAULT_SND_BUF_SIZE) ")");
 
@@ -166,10 +166,10 @@ struct usbatm_control {
 
 /* ATM */
 
-static void usbatm_atm_dev_close(struct atm_dev *dev);
+static void usbatm_atm_dev_close(struct atm_dev *atm_dev);
 static int usbatm_atm_open(struct atm_vcc *vcc);
 static void usbatm_atm_close(struct atm_vcc *vcc);
-static int usbatm_atm_ioctl(struct atm_dev *dev, unsigned int cmd, void __user * arg);
+static int usbatm_atm_ioctl(struct atm_dev *atm_dev, unsigned int cmd, void __user * arg);
 static int usbatm_atm_send(struct atm_vcc *vcc, struct sk_buff *skb);
 static int usbatm_atm_proc_read(struct atm_dev *atm_dev, loff_t * pos, char *page);
 
@@ -199,7 +199,7 @@ static inline void usbatm_pop(struct atm_vcc *vcc, struct sk_buff *skb)
         if (vcc->pop)
                 vcc->pop(vcc, skb);
         else
-                dev_kfree_skb(skb);
+                dev_kfree_skb_any(skb);
 }
 
 
@@ -234,8 +234,9 @@ static int usbatm_submit_urb(struct urb *urb)
 
         ret = usb_submit_urb(urb, GFP_ATOMIC);
         if (ret) {
-                atm_dbg(channel->usbatm, "%s: urb 0x%p submission failed (%d)!\n",
-                        __func__, urb, ret);
+                if (printk_ratelimit())
+                        atm_warn(channel->usbatm, "%s: urb 0x%p submission failed (%d)!\n",
+                                __func__, urb, ret);
 
                 /* consider all errors transient and return the buffer back to the queue */
                 urb->status = -EAGAIN;
@@ -269,10 +270,16 @@ static void usbatm_complete(struct urb *urb, struct pt_regs *regs)
 
         spin_unlock_irqrestore(&channel->lock, flags);
 
-        if (unlikely(urb->status))
+        if (unlikely(urb->status) &&
+                        (!(channel->usbatm->flags & UDSL_IGNORE_EILSEQ) ||
+                         urb->status != -EILSEQ ))
+        {
+                if (printk_ratelimit())
+                        atm_warn(channel->usbatm, "%s: urb 0x%p failed (%d)!\n",
+                                __func__, urb, urb->status);
                 /* throttle processing in case of an error */
                 mod_timer(&channel->delay, jiffies + msecs_to_jiffies(THROTTLE_MSECS));
-        else
+        } else
                 tasklet_schedule(&channel->tasklet);
 }
 
@@ -284,129 +291,167 @@ static void usbatm_complete(struct urb *urb, struct pt_regs *regs)
 static inline struct usbatm_vcc_data *usbatm_find_vcc(struct usbatm_data *instance,
                                                   short vpi, int vci)
 {
-        struct usbatm_vcc_data *vcc;
+        struct usbatm_vcc_data *vcc_data;
 
-        list_for_each_entry(vcc, &instance->vcc_list, list)
-                if ((vcc->vci == vci) && (vcc->vpi == vpi))
-                        return vcc;
+        list_for_each_entry(vcc_data, &instance->vcc_list, list)
+                if ((vcc_data->vci == vci) && (vcc_data->vpi == vpi))
+                        return vcc_data;
         return NULL;
 }
 
-static void usbatm_extract_cells(struct usbatm_data *instance,
-                               unsigned char *source, unsigned int avail_data)
+static void usbatm_extract_one_cell(struct usbatm_data *instance, unsigned char *source)
 {
-        struct usbatm_vcc_data *cached_vcc = NULL;
         struct atm_vcc *vcc;
         struct sk_buff *sarb;
-        unsigned int stride = instance->rx_channel.stride;
-        int vci, cached_vci = 0;
-        short vpi, cached_vpi = 0;
-        u8 pti;
+        short vpi = ((source[0] & 0x0f) << 4)  | (source[1] >> 4);
+        int vci = ((source[1] & 0x0f) << 12) | (source[2] << 4) | (source[3] >> 4);
+        u8 pti = ((source[3] & 0xe) >> 1);
 
-        for (; avail_data >= stride; avail_data -= stride, source += stride) {
-                vpi = ((source[0] & 0x0f) << 4)  | (source[1] >> 4);
-                vci = ((source[1] & 0x0f) << 12) | (source[2] << 4) | (source[3] >> 4);
-                pti = ((source[3] & 0xe) >> 1);
+        vdbg("%s: vpi %hd, vci %d, pti %d", __func__, vpi, vci, pti);
 
-                vdbg("%s: vpi %hd, vci %d, pti %d", __func__, vpi, vci, pti);
+        if ((vci != instance->cached_vci) || (vpi != instance->cached_vpi)) {
+                instance->cached_vpi = vpi;
+                instance->cached_vci = vci;
 
-                if ((vci != cached_vci) || (vpi != cached_vpi)) {
-                        cached_vpi = vpi;
-                        cached_vci = vci;
+                instance->cached_vcc = usbatm_find_vcc(instance, vpi, vci);
 
-                        cached_vcc = usbatm_find_vcc(instance, vpi, vci);
+                if (!instance->cached_vcc)
+                        atm_rldbg(instance, "%s: unknown vpi/vci (%hd/%d)!\n", __func__, vpi, vci);
+        }
 
-                        if (!cached_vcc)
-                                atm_dbg(instance, "%s: unknown vpi/vci (%hd/%d)!\n", __func__, vpi, vci);
-                }
+        if (!instance->cached_vcc)
+                return;
 
-                if (!cached_vcc)
-                        continue;
+        vcc = instance->cached_vcc->vcc;
 
-                vcc = cached_vcc->vcc;
+        /* OAM F5 end-to-end */
+        if (pti == ATM_PTI_E2EF5) {
+                if (printk_ratelimit())
+                        atm_warn(instance, "%s: OAM not supported (vpi %d, vci %d)!\n",
+                                __func__, vpi, vci);
+                atomic_inc(&vcc->stats->rx_err);
+                return;
+        }
 
-                /* OAM F5 end-to-end */
-                if (pti == ATM_PTI_E2EF5) {
-                        atm_warn(instance, "%s: OAM not supported (vpi %d, vci %d)!\n", __func__, vpi, vci);
-                        atomic_inc(&vcc->stats->rx_err);
-                        continue;
-                }
+        sarb = instance->cached_vcc->sarb;
 
-                sarb = cached_vcc->sarb;
+        if (sarb->tail + ATM_CELL_PAYLOAD > sarb->end) {
+                atm_rldbg(instance, "%s: buffer overrun (sarb->len %u, vcc: 0x%p)!\n",
+                                __func__, sarb->len, vcc);
+                /* discard cells already received */
+                skb_trim(sarb, 0);
+                UDSL_ASSERT(sarb->tail + ATM_CELL_PAYLOAD <= sarb->end);
+        }
 
-                if (sarb->tail + ATM_CELL_PAYLOAD > sarb->end) {
-                        atm_dbg(instance, "%s: buffer overrun (sarb->len %u, vcc: 0x%p)!\n",
-                                        __func__, sarb->len, vcc);
-                        /* discard cells already received */
-                        skb_trim(sarb, 0);
-                        UDSL_ASSERT(sarb->tail + ATM_CELL_PAYLOAD <= sarb->end);
-                }
+        memcpy(sarb->tail, source + ATM_CELL_HEADER, ATM_CELL_PAYLOAD);
+        __skb_put(sarb, ATM_CELL_PAYLOAD);
 
-                memcpy(sarb->tail, source + ATM_CELL_HEADER, ATM_CELL_PAYLOAD);
-                __skb_put(sarb, ATM_CELL_PAYLOAD);
+        if (pti & 1) {
+                struct sk_buff *skb;
+                unsigned int length;
+                unsigned int pdu_length;
 
-                if (pti & 1) {
-                        struct sk_buff *skb;
-                        unsigned int length;
-                        unsigned int pdu_length;
+                length = (source[ATM_CELL_SIZE - 6] << 8) + source[ATM_CELL_SIZE - 5];
 
-                        length = (source[ATM_CELL_SIZE - 6] << 8) + source[ATM_CELL_SIZE - 5];
+                /* guard against overflow */
+                if (length > ATM_MAX_AAL5_PDU) {
+                        atm_rldbg(instance, "%s: bogus length %u (vcc: 0x%p)!\n",
+                                  __func__, length, vcc);
+                        atomic_inc(&vcc->stats->rx_err);
+                        goto out;
+                }
 
-                        /* guard against overflow */
-                        if (length > ATM_MAX_AAL5_PDU) {
-                                atm_dbg(instance, "%s: bogus length %u (vcc: 0x%p)!\n",
-                                                __func__, length, vcc);
-                                atomic_inc(&vcc->stats->rx_err);
-                                goto out;
-                        }
+                pdu_length = usbatm_pdu_length(length);
 
-                        pdu_length = usbatm_pdu_length(length);
+                if (sarb->len < pdu_length) {
+                        atm_rldbg(instance, "%s: bogus pdu_length %u (sarb->len: %u, vcc: 0x%p)!\n",
+                                  __func__, pdu_length, sarb->len, vcc);
+                        atomic_inc(&vcc->stats->rx_err);
+                        goto out;
+                }
 
-                        if (sarb->len < pdu_length) {
-                                atm_dbg(instance, "%s: bogus pdu_length %u (sarb->len: %u, vcc: 0x%p)!\n",
-                                                __func__, pdu_length, sarb->len, vcc);
-                                atomic_inc(&vcc->stats->rx_err);
-                                goto out;
-                        }
+                if (crc32_be(~0, sarb->tail - pdu_length, pdu_length) != 0xc704dd7b) {
+                        atm_rldbg(instance, "%s: packet failed crc check (vcc: 0x%p)!\n",
+                                  __func__, vcc);
+                        atomic_inc(&vcc->stats->rx_err);
+                        goto out;
+                }
 
-                        if (crc32_be(~0, sarb->tail - pdu_length, pdu_length) != 0xc704dd7b) {
-                                atm_dbg(instance, "%s: packet failed crc check (vcc: 0x%p)!\n",
-                                                __func__, vcc);
-                                atomic_inc(&vcc->stats->rx_err);
-                                goto out;
-                        }
+                vdbg("%s: got packet (length: %u, pdu_length: %u, vcc: 0x%p)", __func__, length, pdu_length, vcc);
 
-                        vdbg("%s: got packet (length: %u, pdu_length: %u, vcc: 0x%p)", __func__, length, pdu_length, vcc);
+                if (!(skb = dev_alloc_skb(length))) {
+                        if (printk_ratelimit())
+                                atm_err(instance, "%s: no memory for skb (length: %u)!\n",
+                                        __func__, length);
+                        atomic_inc(&vcc->stats->rx_drop);
+                        goto out;
+                }
 
-                        if (!(skb = dev_alloc_skb(length))) {
-                                atm_dbg(instance, "%s: no memory for skb (length: %u)!\n", __func__, length);
-                                atomic_inc(&vcc->stats->rx_drop);
-                                goto out;
-                        }
+                vdbg("%s: allocated new sk_buff (skb: 0x%p, skb->truesize: %u)", __func__, skb, skb->truesize);
 
-                        vdbg("%s: allocated new sk_buff (skb: 0x%p, skb->truesize: %u)", __func__, skb, skb->truesize);
+                if (!atm_charge(vcc, skb->truesize)) {
+                        atm_rldbg(instance, "%s: failed atm_charge (skb->truesize: %u)!\n",
+                                  __func__, skb->truesize);
+                        dev_kfree_skb_any(skb);
+                        goto out;       /* atm_charge increments rx_drop */
+                }
 
-                        if (!atm_charge(vcc, skb->truesize)) {
-                                atm_dbg(instance, "%s: failed atm_charge (skb->truesize: %u)!\n", __func__, skb->truesize);
-                                dev_kfree_skb(skb);
-                                goto out;       /* atm_charge increments rx_drop */
-                        }
+                memcpy(skb->data, sarb->tail - pdu_length, length);
+                __skb_put(skb, length);
 
-                        memcpy(skb->data, sarb->tail - pdu_length, length);
-                        __skb_put(skb, length);
+                vdbg("%s: sending skb 0x%p, skb->len %u, skb->truesize %u",
+                     __func__, skb, skb->len, skb->truesize);
 
-                        vdbg("%s: sending skb 0x%p, skb->len %u, skb->truesize %u",
-                             __func__, skb, skb->len, skb->truesize);
+                PACKETDEBUG(skb->data, skb->len);
 
-                        PACKETDEBUG(skb->data, skb->len);
+                vcc->push(vcc, skb);
 
-                        vcc->push(vcc, skb);
+                atomic_inc(&vcc->stats->rx);
+        out:
+                skb_trim(sarb, 0);
+        }
+}
 
-                        atomic_inc(&vcc->stats->rx);
-                out:
-                        skb_trim(sarb, 0);
+static void usbatm_extract_cells(struct usbatm_data *instance,
+                unsigned char *source, unsigned int avail_data)
+{
+        unsigned int stride = instance->rx_channel.stride;
+        unsigned int buf_usage = instance->buf_usage;
+
+        /* extract cells from incoming data, taking into account that
+         * the length of avail data may not be a multiple of stride */
+
+        if (buf_usage > 0) {
+                /* we have a partially received atm cell */
+                unsigned char *cell_buf = instance->cell_buf;
+                unsigned int space_left = stride - buf_usage;
+
+                UDSL_ASSERT(buf_usage <= stride);
+
+                if (avail_data >= space_left) {
+                        /* add new data and process cell */
+                        memcpy(cell_buf + buf_usage, source, space_left);
+                        source += space_left;
+                        avail_data -= space_left;
+                        usbatm_extract_one_cell(instance, cell_buf);
+                        instance->buf_usage = 0;
+                } else {
+                        /* not enough data to fill the cell */
+                        memcpy(cell_buf + buf_usage, source, avail_data);
+                        instance->buf_usage = buf_usage + avail_data;
+                        return;
                 }
         }
+
+        for (; avail_data >= stride; avail_data -= stride, source += stride)
+                usbatm_extract_one_cell(instance, source);
+
+        if (avail_data > 0) {
+                /* length was not a multiple of stride -
+                 * save remaining data for next call */
+                memcpy(instance->cell_buf, source, avail_data);
+                instance->buf_usage = avail_data;
+        }
 }
 
 
@@ -420,14 +465,14 @@ static unsigned int usbatm_write_cells(struct usbatm_data *instance,
 {
         struct usbatm_control *ctrl = UDSL_SKB(skb);
         struct atm_vcc *vcc = ctrl->atm.vcc;
-        unsigned int num_written;
+        unsigned int bytes_written;
         unsigned int stride = instance->tx_channel.stride;
 
         vdbg("%s: skb->len=%d, avail_space=%u", __func__, skb->len, avail_space);
         UDSL_ASSERT(!(avail_space % stride));
 
-        for (num_written = 0; num_written < avail_space && ctrl->len;
-             num_written += stride, target += stride) {
+        for (bytes_written = 0; bytes_written < avail_space && ctrl->len;
+             bytes_written += stride, target += stride) {
                 unsigned int data_len = min_t(unsigned int, skb->len, ATM_CELL_PAYLOAD);
                 unsigned int left = ATM_CELL_PAYLOAD - data_len;
                 u8 *ptr = target;
@@ -470,7 +515,7 @@ static unsigned int usbatm_write_cells(struct usbatm_data *instance,
                         ctrl->crc = crc32_be(ctrl->crc, ptr, left);
         }
 
-        return num_written;
+        return bytes_written;
 }
 
 
@@ -487,16 +532,40 @@ static void usbatm_rx_process(unsigned long data)
                 vdbg("%s: processing urb 0x%p", __func__, urb);
 
                 if (usb_pipeisoc(urb->pipe)) {
+                        unsigned char *merge_start = NULL;
+                        unsigned int merge_length = 0;
+                        const unsigned int packet_size = instance->rx_channel.packet_size;
                         int i;
-                        for (i = 0; i < urb->number_of_packets; i++)
-                                if (!urb->iso_frame_desc[i].status)
-                                        usbatm_extract_cells(instance,
-                                                             (u8 *)urb->transfer_buffer + urb->iso_frame_desc[i].offset,
-                                                             urb->iso_frame_desc[i].actual_length);
-                }
-                else
+
+                        for (i = 0; i < urb->number_of_packets; i++) {
+                                if (!urb->iso_frame_desc[i].status) {
+                                        unsigned int actual_length = urb->iso_frame_desc[i].actual_length;
+
+                                        UDSL_ASSERT(actual_length <= packet_size);
+
+                                        if (!merge_length)
+                                                merge_start = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset;
+                                        merge_length += actual_length;
+                                        if (merge_length && (actual_length < packet_size)) {
+                                                usbatm_extract_cells(instance, merge_start, merge_length);
+                                                merge_length = 0;
+                                        }
+                                } else {
+                                        atm_rldbg(instance, "%s: status %d in frame %d!\n", __func__, urb->status, i);
+                                        if (merge_length)
+                                                usbatm_extract_cells(instance, merge_start, merge_length);
+                                        merge_length = 0;
+                                        instance->buf_usage = 0;
+                                }
+                        }
+
+                        if (merge_length)
+                                usbatm_extract_cells(instance, merge_start, merge_length);
+                } else
                         if (!urb->status)
                                 usbatm_extract_cells(instance, urb->transfer_buffer, urb->actual_length);
+                        else
+                                instance->buf_usage = 0;
 
                 if (usbatm_submit_urb(urb))
                         return;
@@ -514,7 +583,7 @@ static void usbatm_tx_process(unsigned long data)
         struct sk_buff *skb = instance->current_skb;
         struct urb *urb = NULL;
         const unsigned int buf_size = instance->tx_channel.buf_size;
-        unsigned int num_written = 0;
+        unsigned int bytes_written = 0;
         u8 *buffer = NULL;
 
         if (!skb)
@@ -526,16 +595,16 @@ static void usbatm_tx_process(unsigned long data)
                         if (!urb)
                                 break;          /* no more senders */
                         buffer = urb->transfer_buffer;
-                        num_written = (urb->status == -EAGAIN) ?
+                        bytes_written = (urb->status == -EAGAIN) ?
                                 urb->transfer_buffer_length : 0;
                 }
 
-                num_written += usbatm_write_cells(instance, skb,
-                                                  buffer + num_written,
-                                                  buf_size - num_written);
+                bytes_written += usbatm_write_cells(instance, skb,
+                                                  buffer + bytes_written,
+                                                  buf_size - bytes_written);
 
                 vdbg("%s: wrote %u bytes from skb 0x%p to urb 0x%p",
-                     __func__, num_written, skb, urb);
+                     __func__, bytes_written, skb, urb);
 
                 if (!UDSL_SKB(skb)->len) {
                         struct atm_vcc *vcc = UDSL_SKB(skb)->atm.vcc;
@@ -546,8 +615,8 @@ static void usbatm_tx_process(unsigned long data)
                         skb = skb_dequeue(&instance->sndqueue);
                 }
 
-                if (num_written == buf_size || (!skb && num_written)) {
-                        urb->transfer_buffer_length = num_written;
+                if (bytes_written == buf_size || (!skb && bytes_written)) {
+                        urb->transfer_buffer_length = bytes_written;
 
                         if (usbatm_submit_urb(urb))
                                 break;
@@ -593,20 +662,24 @@ static int usbatm_atm_send(struct atm_vcc *vcc, struct sk_buff *skb)
 
         vdbg("%s called (skb 0x%p, len %u)", __func__, skb, skb->len);
 
-        if (!instance) {
-                dbg("%s: NULL data!", __func__);
+        /* racy disconnection check - fine */
+        if (!instance || instance->disconnected) {
+#ifdef DEBUG
+                if (printk_ratelimit())
+                        printk(KERN_DEBUG "%s: %s!\n", __func__, instance ? "disconnected" : "NULL instance");
+#endif
                 err = -ENODEV;
                 goto fail;
         }
 
         if (vcc->qos.aal != ATM_AAL5) {
-                atm_dbg(instance, "%s: unsupported ATM type %d!\n", __func__, vcc->qos.aal);
+                atm_rldbg(instance, "%s: unsupported ATM type %d!\n", __func__, vcc->qos.aal);
                 err = -EINVAL;
                 goto fail;
         }
 
         if (skb->len > ATM_MAX_AAL5_PDU) {
-                atm_dbg(instance, "%s: packet too long (%d vs %d)!\n",
+                atm_rldbg(instance, "%s: packet too long (%d vs %d)!\n",
                                 __func__, skb->len, ATM_MAX_AAL5_PDU);
                 err = -EINVAL;
                 goto fail;
@@ -665,16 +738,16 @@ static void usbatm_put_instance(struct usbatm_data *instance)
 **  ATM  **
 **********/
 
-static void usbatm_atm_dev_close(struct atm_dev *dev)
+static void usbatm_atm_dev_close(struct atm_dev *atm_dev)
 {
-        struct usbatm_data *instance = dev->dev_data;
+        struct usbatm_data *instance = atm_dev->dev_data;
 
         dbg("%s", __func__);
 
         if (!instance)
                 return;
 
-        dev->dev_data = NULL;
+        atm_dev->dev_data = NULL; /* catch bugs */
         usbatm_put_instance(instance);  /* taken in usbatm_atm_init */
 }
 
@@ -706,15 +779,19 @@ static int usbatm_atm_proc_read(struct atm_dev *atm_dev, loff_t * pos, char *pag
                                atomic_read(&atm_dev->stats.aal5.rx_err),
                                atomic_read(&atm_dev->stats.aal5.rx_drop));
 
-        if (!left--)
-                switch (atm_dev->signal) {
-                case ATM_PHY_SIG_FOUND:
-                        return sprintf(page, "Line up\n");
-                case ATM_PHY_SIG_LOST:
-                        return sprintf(page, "Line down\n");
-                default:
-                        return sprintf(page, "Line state unknown\n");
-                }
+        if (!left--) {
+                if (instance->disconnected)
+                        return sprintf(page, "Disconnected\n");
+                else
+                        switch (atm_dev->signal) {
+                        case ATM_PHY_SIG_FOUND:
+                                return sprintf(page, "Line up\n");
+                        case ATM_PHY_SIG_LOST:
+                                return sprintf(page, "Line down\n");
+                        default:
+                                return sprintf(page, "Line state unknown\n");
+                        }
+        }
 
         return 0;
 }
@@ -735,13 +812,24 @@ static int usbatm_atm_open(struct atm_vcc *vcc)
         atm_dbg(instance, "%s: vpi %hd, vci %d\n", __func__, vpi, vci);
 
         /* only support AAL5 */
-        if ((vcc->qos.aal != ATM_AAL5) || (vcc->qos.rxtp.max_sdu < 0)
-            || (vcc->qos.rxtp.max_sdu > ATM_MAX_AAL5_PDU)) {
-                atm_dbg(instance, "%s: unsupported ATM type %d!\n", __func__, vcc->qos.aal);
+        if ((vcc->qos.aal != ATM_AAL5)) {
+                atm_warn(instance, "%s: unsupported ATM type %d!\n", __func__, vcc->qos.aal);
+                return -EINVAL;
+        }
+
+        /* sanity checks */
+        if ((vcc->qos.rxtp.max_sdu < 0) || (vcc->qos.rxtp.max_sdu > ATM_MAX_AAL5_PDU)) {
+                atm_dbg(instance, "%s: max_sdu %d out of range!\n", __func__, vcc->qos.rxtp.max_sdu);
                 return -EINVAL;
         }
 
-        down(&instance->serialize);     /* vs self, usbatm_atm_close */
+        mutex_lock(&instance->serialize);       /* vs self, usbatm_atm_close, usbatm_usb_disconnect */
+
+        if (instance->disconnected) {
+                atm_dbg(instance, "%s: disconnected!\n", __func__);
+                ret = -ENODEV;
+                goto fail;
+        }
 
         if (usbatm_find_vcc(instance, vpi, vci)) {
                 atm_dbg(instance, "%s: %hd/%d already in use!\n", __func__, vpi, vci);
@@ -749,20 +837,19 @@ static int usbatm_atm_open(struct atm_vcc *vcc)
                 goto fail;
         }
 
-        if (!(new = kmalloc(sizeof(struct usbatm_vcc_data), GFP_KERNEL))) {
-                atm_dbg(instance, "%s: no memory for vcc_data!\n", __func__);
+        if (!(new = kzalloc(sizeof(struct usbatm_vcc_data), GFP_KERNEL))) {
+                atm_err(instance, "%s: no memory for vcc_data!\n", __func__);
                 ret = -ENOMEM;
                 goto fail;
         }
 
-        memset(new, 0, sizeof(struct usbatm_vcc_data));
         new->vcc = vcc;
         new->vpi = vpi;
         new->vci = vci;
 
         new->sarb = alloc_skb(usbatm_pdu_length(vcc->qos.rxtp.max_sdu), GFP_KERNEL);
         if (!new->sarb) {
-                atm_dbg(instance, "%s: no memory for SAR buffer!\n", __func__);
+                atm_err(instance, "%s: no memory for SAR buffer!\n", __func__);
                 ret = -ENOMEM;
                 goto fail;
         }
@@ -770,6 +857,9 @@ static int usbatm_atm_open(struct atm_vcc *vcc)
         vcc->dev_data = new;
 
         tasklet_disable(&instance->rx_channel.tasklet);
+        instance->cached_vcc = new;
+        instance->cached_vpi = vpi;
+        instance->cached_vci = vci;
         list_add(&new->list, &instance->vcc_list);
         tasklet_enable(&instance->rx_channel.tasklet);
 
@@ -777,7 +867,7 @@ static int usbatm_atm_open(struct atm_vcc *vcc)
         set_bit(ATM_VF_PARTIAL, &vcc->flags);
         set_bit(ATM_VF_READY, &vcc->flags);
 
-        up(&instance->serialize);
+        mutex_unlock(&instance->serialize);
 
         atm_dbg(instance, "%s: allocated vcc data 0x%p\n", __func__, new);
 
@@ -785,7 +875,7 @@ static int usbatm_atm_open(struct atm_vcc *vcc)
 
 fail:
         kfree(new);
-        up(&instance->serialize);
+        mutex_unlock(&instance->serialize);
         return ret;
 }
 
@@ -806,9 +896,14 @@ static void usbatm_atm_close(struct atm_vcc *vcc)
 
         usbatm_cancel_send(instance, vcc);
 
-        down(&instance->serialize);     /* vs self, usbatm_atm_open */
+        mutex_lock(&instance->serialize);       /* vs self, usbatm_atm_open, usbatm_usb_disconnect */
 
         tasklet_disable(&instance->rx_channel.tasklet);
+        if (instance->cached_vcc == vcc_data) {
+                instance->cached_vcc = NULL;
+                instance->cached_vpi = ATM_VPI_UNSPEC;
+                instance->cached_vci = ATM_VCI_UNSPEC;
+        }
         list_del(&vcc_data->list);
         tasklet_enable(&instance->rx_channel.tasklet);
 
@@ -824,14 +919,21 @@ static void usbatm_atm_close(struct atm_vcc *vcc)
         clear_bit(ATM_VF_PARTIAL, &vcc->flags);
         clear_bit(ATM_VF_ADDR, &vcc->flags);
 
-        up(&instance->serialize);
+        mutex_unlock(&instance->serialize);
 
         atm_dbg(instance, "%s successful\n", __func__);
 }
 
-static int usbatm_atm_ioctl(struct atm_dev *dev, unsigned int cmd,
+static int usbatm_atm_ioctl(struct atm_dev *atm_dev, unsigned int cmd,
                           void __user * arg)
 {
+        struct usbatm_data *instance = atm_dev->dev_data;
+
+        if (!instance || instance->disconnected) {
+                dbg("%s: %s!", __func__, instance ? "disconnected" : "NULL instance");
+                return -ENODEV;
+        }
+
         switch (cmd) {
         case ATM_QUERYLOOP:
                 return put_user(ATM_LM_NONE, (int __user *)arg) ? -EFAULT : 0;
@@ -845,10 +947,13 @@ static int usbatm_atm_init(struct usbatm_data *instance)
         struct atm_dev *atm_dev;
         int ret, i;
 
-        /* ATM init */
+        /* ATM init.  The ATM initialization scheme suffers from an intrinsic race
+         * condition: callbacks we register can be executed at once, before we have
+         * initialized the struct atm_dev.  To protect against this, all callbacks
+         * abort if atm_dev->dev_data is NULL. */
         atm_dev = atm_dev_register(instance->driver_name, &usbatm_atm_devops, -1, NULL);
         if (!atm_dev) {
-                usb_dbg(instance, "%s: failed to register ATM device!\n", __func__);
+                usb_err(instance, "%s: failed to register ATM device!\n", __func__);
                 return -1;
         }
 
@@ -862,12 +967,13 @@ static int usbatm_atm_init(struct usbatm_data *instance)
         atm_dev->link_rate = 128 * 1000 / 424;
 
         if (instance->driver->atm_start && ((ret = instance->driver->atm_start(instance, atm_dev)) < 0)) {
-                atm_dbg(instance, "%s: atm_start failed: %d!\n", __func__, ret);
+                atm_err(instance, "%s: atm_start failed: %d!\n", __func__, ret);
                 goto fail;
         }
 
-        /* ready for ATM callbacks */
         usbatm_get_instance(instance);  /* dropped in usbatm_atm_dev_close */
+
+        /* ready for ATM callbacks */
         mb();
         atm_dev->dev_data = instance;
 
@@ -903,9 +1009,9 @@ static int usbatm_do_heavy_init(void *arg)
         if (!ret)
                 ret = usbatm_atm_init(instance);
 
-        down(&instance->serialize);
+        mutex_lock(&instance->serialize);
         instance->thread_pid = -1;
-        up(&instance->serialize);
+        mutex_unlock(&instance->serialize);
 
         complete_and_exit(&instance->thread_exited, ret);
 }
@@ -915,13 +1021,13 @@ static int usbatm_heavy_init(struct usbatm_data *instance)
         int ret = kernel_thread(usbatm_do_heavy_init, instance, CLONE_KERNEL);
 
         if (ret < 0) {
-                usb_dbg(instance, "%s: failed to create kernel_thread (%d)!\n", __func__, ret);
+                usb_err(instance, "%s: failed to create kernel_thread (%d)!\n", __func__, ret);
                 return ret;
         }
 
-        down(&instance->serialize);
+        mutex_lock(&instance->serialize);
         instance->thread_pid = ret;
-        up(&instance->serialize);
+        mutex_unlock(&instance->serialize);
 
         wait_for_completion(&instance->thread_started);
 
@@ -951,9 +1057,9 @@ int usbatm_usb_probe(struct usb_interface *intf, const struct usb_device_id *id,
         char *buf;
         int error = -ENOMEM;
         int i, length;
-        int need_heavy;
+        unsigned int maxpacket, num_packets;
 
-        dev_dbg(dev, "%s: trying driver %s with vendor=0x%x, product=0x%x, ifnum %d\n",
+        dev_dbg(dev, "%s: trying driver %s with vendor=%04x, product=%04x, ifnum %2d\n",
                         __func__, driver->driver_name,
                         le16_to_cpu(usb_dev->descriptor.idVendor),
                         le16_to_cpu(usb_dev->descriptor.idProduct),
@@ -962,7 +1068,7 @@ int usbatm_usb_probe(struct usb_interface *intf, const struct usb_device_id *id,
         /* instance init */
         instance = kzalloc(sizeof(*instance) + sizeof(struct urb *) * (num_rcv_urbs + num_snd_urbs), GFP_KERNEL);
         if (!instance) {
-                dev_dbg(dev, "%s: no memory for instance data!\n", __func__);
+                dev_err(dev, "%s: no memory for instance data!\n", __func__);
                 return -ENOMEM;
         }
 
@@ -996,66 +1102,96 @@ int usbatm_usb_probe(struct usb_interface *intf, const struct usb_device_id *id,
         snprintf(buf, length, ")");
 
  bind:
-        need_heavy = 1;
-        if (driver->bind && (error = driver->bind(instance, intf, id, &need_heavy)) < 0) {
-                        dev_dbg(dev, "%s: bind failed: %d!\n", __func__, error);
+        if (driver->bind && (error = driver->bind(instance, intf, id)) < 0) {
+                        dev_err(dev, "%s: bind failed: %d!\n", __func__, error);
                         goto fail_free;
         }
 
         /* private fields */
 
         kref_init(&instance->refcount);         /* dropped in usbatm_usb_disconnect */
-        init_MUTEX(&instance->serialize);
+        mutex_init(&instance->serialize);
 
         instance->thread_pid = -1;
         init_completion(&instance->thread_started);
         init_completion(&instance->thread_exited);
 
         INIT_LIST_HEAD(&instance->vcc_list);
+        skb_queue_head_init(&instance->sndqueue);
 
         usbatm_init_channel(&instance->rx_channel);
         usbatm_init_channel(&instance->tx_channel);
         tasklet_init(&instance->rx_channel.tasklet, usbatm_rx_process, (unsigned long)instance);
         tasklet_init(&instance->tx_channel.tasklet, usbatm_tx_process, (unsigned long)instance);
-        instance->rx_channel.endpoint = usb_rcvbulkpipe(usb_dev, driver->in);
-        instance->tx_channel.endpoint = usb_sndbulkpipe(usb_dev, driver->out);
         instance->rx_channel.stride = ATM_CELL_SIZE + driver->rx_padding;
         instance->tx_channel.stride = ATM_CELL_SIZE + driver->tx_padding;
-        instance->rx_channel.buf_size = rcv_buf_size * instance->rx_channel.stride;
-        instance->tx_channel.buf_size = snd_buf_size * instance->tx_channel.stride;
         instance->rx_channel.usbatm = instance->tx_channel.usbatm = instance;
 
-        skb_queue_head_init(&instance->sndqueue);
+        if ((instance->flags & UDSL_USE_ISOC) && driver->isoc_in)
+                instance->rx_channel.endpoint = usb_rcvisocpipe(usb_dev, driver->isoc_in);
+        else
+                instance->rx_channel.endpoint = usb_rcvbulkpipe(usb_dev, driver->bulk_in);
+
+        instance->tx_channel.endpoint = usb_sndbulkpipe(usb_dev, driver->bulk_out);
+
+        /* tx buffer size must be a positive multiple of the stride */
+        instance->tx_channel.buf_size = max (instance->tx_channel.stride,
+                        snd_buf_bytes - (snd_buf_bytes % instance->tx_channel.stride));
+
+        /* rx buffer size must be a positive multiple of the endpoint maxpacket */
+        maxpacket = usb_maxpacket(usb_dev, instance->rx_channel.endpoint, 0);
+
+        if ((maxpacket < 1) || (maxpacket > UDSL_MAX_BUF_SIZE)) {
+                dev_err(dev, "%s: invalid endpoint %02x!\n", __func__,
+                                usb_pipeendpoint(instance->rx_channel.endpoint));
+                error = -EINVAL;
+                goto fail_unbind;
+        }
+
+        num_packets = max (1U, (rcv_buf_bytes + maxpacket / 2) / maxpacket); /* round */
+
+        if (num_packets * maxpacket > UDSL_MAX_BUF_SIZE)
+                num_packets--;
+
+        instance->rx_channel.buf_size = num_packets * maxpacket;
+        instance->rx_channel.packet_size = maxpacket;
+
+#ifdef DEBUG
+        for (i = 0; i < 2; i++) {
+                struct usbatm_channel *channel = i ?
+                        &instance->tx_channel : &instance->rx_channel;
+
+                dev_dbg(dev, "%s: using %d byte buffer for %s channel 0x%p\n", __func__, channel->buf_size, i ? "tx" : "rx", channel);
+        }
+#endif
+
+        /* initialize urbs */
 
         for (i = 0; i < num_rcv_urbs + num_snd_urbs; i++) {
-                struct urb *urb;
                 u8 *buffer;
-                unsigned int iso_packets = 0, iso_size = 0;
                 struct usbatm_channel *channel = i < num_rcv_urbs ?
                         &instance->rx_channel : &instance->tx_channel;
+                struct urb *urb;
+                unsigned int iso_packets = usb_pipeisoc(channel->endpoint) ? channel->buf_size / channel->packet_size : 0;
 
-                if (usb_pipeisoc(channel->endpoint)) {
-                        /* don't expect iso out endpoints */
-                        iso_size = usb_maxpacket(instance->usb_dev, channel->endpoint, 0);
-                        iso_size -= iso_size % channel->stride; /* alignment */
-                        BUG_ON(!iso_size);
-                        iso_packets = (channel->buf_size - 1) / iso_size + 1;
-                }
+                UDSL_ASSERT(!usb_pipeisoc(channel->endpoint) || usb_pipein(channel->endpoint));
 
                 urb = usb_alloc_urb(iso_packets, GFP_KERNEL);
                 if (!urb) {
-                        dev_dbg(dev, "%s: no memory for urb %d!\n", __func__, i);
+                        dev_err(dev, "%s: no memory for urb %d!\n", __func__, i);
+                        error = -ENOMEM;
                         goto fail_unbind;
                 }
 
                 instance->urbs[i] = urb;
 
-                buffer = kmalloc(channel->buf_size, GFP_KERNEL);
+                /* zero the tx padding to avoid leaking information */
+                buffer = kzalloc(channel->buf_size, GFP_KERNEL);
                 if (!buffer) {
-                        dev_dbg(dev, "%s: no memory for buffer %d!\n", __func__, i);
+                        dev_err(dev, "%s: no memory for buffer %d!\n", __func__, i);
+                        error = -ENOMEM;
                         goto fail_unbind;
                 }
-                memset(buffer, 0, channel->buf_size);
 
                 usb_fill_bulk_urb(urb, instance->usb_dev, channel->endpoint,
                                   buffer, channel->buf_size, usbatm_complete, channel);
@@ -1065,9 +1201,8 @@ int usbatm_usb_probe(struct usb_interface *intf, const struct usb_device_id *id,
                         urb->transfer_flags = URB_ISO_ASAP;
                         urb->number_of_packets = iso_packets;
                         for (j = 0; j < iso_packets; j++) {
-                                urb->iso_frame_desc[j].offset = iso_size * j;
-                                urb->iso_frame_desc[j].length = min_t(int, iso_size,
-                                                                      channel->buf_size - urb->iso_frame_desc[j].offset);
+                                urb->iso_frame_desc[j].offset = channel->packet_size * j;
+                                urb->iso_frame_desc[j].length = channel->packet_size;
                         }
                 }
 
@@ -1079,7 +1214,17 @@ int usbatm_usb_probe(struct usb_interface *intf, const struct usb_device_id *id,
                      __func__, urb->transfer_buffer, urb->transfer_buffer_length, urb);
         }
 
-        if (need_heavy && driver->heavy_init) {
+        instance->cached_vpi = ATM_VPI_UNSPEC;
+        instance->cached_vci = ATM_VCI_UNSPEC;
+        instance->cell_buf = kmalloc(instance->rx_channel.stride, GFP_KERNEL);
+
+        if (!instance->cell_buf) {
+                dev_err(dev, "%s: no memory for cell buffer!\n", __func__);
+                error = -ENOMEM;
+                goto fail_unbind;
+        }
+
+        if (!(instance->flags & UDSL_SKIP_HEAVY_INIT) && driver->heavy_init) {
                 error = usbatm_heavy_init(instance);
         } else {
                 complete(&instance->thread_exited);     /* pretend that heavy_init was run */
@@ -1098,6 +1243,8 @@ int usbatm_usb_probe(struct usb_interface *intf, const struct usb_device_id *id,
         if (instance->driver->unbind)
                 instance->driver->unbind(instance, intf);
  fail_free:
+        kfree(instance->cell_buf);
+
         for (i = 0; i < num_rcv_urbs + num_snd_urbs; i++) {
                 if (instance->urbs[i])
                         kfree(instance->urbs[i]->transfer_buffer);
@@ -1114,6 +1261,7 @@ void usbatm_usb_disconnect(struct usb_interface *intf)
 {
         struct device *dev = &intf->dev;
         struct usbatm_data *instance = usb_get_intfdata(intf);
+        struct usbatm_vcc_data *vcc_data;
         int i;
 
         dev_dbg(dev, "%s entered\n", __func__);
@@ -1125,13 +1273,19 @@ void usbatm_usb_disconnect(struct usb_interface *intf)
 
         usb_set_intfdata(intf, NULL);
 
-        down(&instance->serialize);
+        mutex_lock(&instance->serialize);
+        instance->disconnected = 1;
         if (instance->thread_pid >= 0)
                 kill_proc(instance->thread_pid, SIGTERM, 1);
-        up(&instance->serialize);
+        mutex_unlock(&instance->serialize);
 
         wait_for_completion(&instance->thread_exited);
 
+        mutex_lock(&instance->serialize);
+        list_for_each_entry(vcc_data, &instance->vcc_list, list)
+                vcc_release_async(vcc_data->vcc, -EPIPE);
+        mutex_unlock(&instance->serialize);
+
         tasklet_disable(&instance->rx_channel.tasklet);
         tasklet_disable(&instance->tx_channel.tasklet);
 
@@ -1141,6 +1295,14 @@ void usbatm_usb_disconnect(struct usb_interface *intf)
         del_timer_sync(&instance->rx_channel.delay);
         del_timer_sync(&instance->tx_channel.delay);
 
+        /* turn usbatm_[rt]x_process into something close to a no-op */
+        /* no need to take the spinlock */
+        INIT_LIST_HEAD(&instance->rx_channel.list);
+        INIT_LIST_HEAD(&instance->tx_channel.list);
+
+        tasklet_enable(&instance->rx_channel.tasklet);
+        tasklet_enable(&instance->tx_channel.tasklet);
+
         if (instance->atm_dev && instance->driver->atm_stop)
                 instance->driver->atm_stop(instance, instance->atm_dev);
 
@@ -1149,19 +1311,13 @@ void usbatm_usb_disconnect(struct usb_interface *intf)
 
         instance->driver_data = NULL;
 
-        /* turn usbatm_[rt]x_process into noop */
-        /* no need to take the spinlock */
-        INIT_LIST_HEAD(&instance->rx_channel.list);
-        INIT_LIST_HEAD(&instance->tx_channel.list);
-
-        tasklet_enable(&instance->rx_channel.tasklet);
-        tasklet_enable(&instance->tx_channel.tasklet);
-
         for (i = 0; i < num_rcv_urbs + num_snd_urbs; i++) {
                 kfree(instance->urbs[i]->transfer_buffer);
                 usb_free_urb(instance->urbs[i]);
         }
 
+        kfree(instance->cell_buf);
+
         /* ATM finalize */
         if (instance->atm_dev)
                 atm_dev_deregister(instance->atm_dev);
@@ -1186,10 +1342,10 @@ static int __init usbatm_usb_init(void)
 
         if ((num_rcv_urbs > UDSL_MAX_RCV_URBS)
             || (num_snd_urbs > UDSL_MAX_SND_URBS)
-            || (rcv_buf_size < 1)
-            || (rcv_buf_size > UDSL_MAX_RCV_BUF_SIZE)
-            || (snd_buf_size < 1)
-            || (snd_buf_size > UDSL_MAX_SND_BUF_SIZE))
+            || (rcv_buf_bytes < 1)
+            || (rcv_buf_bytes > UDSL_MAX_BUF_SIZE)
+            || (snd_buf_bytes < 1)
+            || (snd_buf_bytes > UDSL_MAX_BUF_SIZE))
                 return -EINVAL;
 
         return 0;