From de0e18c999a3ab2ed20a0f2c5a85bf51d86b0fbe Mon Sep 17 00:00:00 2001 From: Bjørn Mork Date: Mon, 8 Oct 2012 13:14:55 +0200 Subject: net: cdc_ncm: refactoring for tx multiplexing MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Adding multiplexed NDP support to cdc_ncm_fill_tx_frame, allowing transmissions of multiple independent sessions within the same NTB. Refactoring the code quite a bit to avoid having to store copies of multiple NDPs being prepared for tx. The old code would still reserve enough room for a maximum sized NDP in the skb so we might as well keep them in the skb while they are being prepared. Signed-off-by: Bjørn Mork --- drivers/net/usb/cdc_ncm.c | 251 +++++++++++++++++++--------------------------- 1 file changed, 105 insertions(+), 146 deletions(-) diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c index fba0783f44f..ae5fd4289da 100644 --- a/drivers/net/usb/cdc_ncm.c +++ b/drivers/net/usb/cdc_ncm.c @@ -88,14 +88,11 @@ (sizeof(struct usb_cdc_ncm_nth16) + sizeof(struct usb_cdc_ncm_ndp16) + \ (CDC_NCM_DPT_DATAGRAMS_MAX + 1) * sizeof(struct usb_cdc_ncm_dpe16)) -struct cdc_ncm_data { - struct usb_cdc_ncm_nth16 nth16; - struct usb_cdc_ncm_ndp16 ndp16; - struct usb_cdc_ncm_dpe16 dpe16[CDC_NCM_DPT_DATAGRAMS_MAX + 1]; -}; +#define CDC_NCM_NDP_SIZE \ + (sizeof(struct usb_cdc_ncm_ndp16) + \ + (CDC_NCM_DPT_DATAGRAMS_MAX + 1) * sizeof(struct usb_cdc_ncm_dpe16)) struct cdc_ncm_ctx { - struct cdc_ncm_data tx_ncm; struct usb_cdc_ncm_ntb_parameters ncm_parm; struct hrtimer tx_timer; struct tasklet_struct bh; @@ -117,13 +114,12 @@ struct cdc_ncm_ctx { struct sk_buff *tx_curr_skb; struct sk_buff *tx_rem_skb; + __le32 tx_rem_sign; spinlock_t mtx; atomic_t stop; u32 tx_timer_pending; - u32 tx_curr_offset; - u32 tx_curr_last_offset; u32 tx_curr_frame_num; u32 rx_speed; u32 tx_speed; @@ -679,51 +675,75 @@ static int cdc_ncm_bind(struct usbnet *dev, struct usb_interface *intf) return ret; } -static void cdc_ncm_zero_fill(u8 *ptr, u32 first, u32 end, u32 max) +static void cdc_ncm_align_tail(struct sk_buff *skb, size_t modulus, size_t remainder, size_t max) { - if (first >= max) - return; - if (first >= end) - return; - if (end > max) - end = max; - memset(ptr + first, 0, end - first); + size_t align = ALIGN(skb->len, modulus) - skb->len + remainder; + + if (skb->len + align > max) + align = max - skb->len; + if (align && skb_tailroom(skb) >= align) + memset(skb_put(skb, align), 0, align); +} + +/* return a pointer to a valid struct usb_cdc_ncm_ndp16 of type sign, possibly + * allocating a new one within skb + */ +static struct usb_cdc_ncm_ndp16 *cdc_ncm_ndp(struct cdc_ncm_ctx *ctx, struct sk_buff *skb, __le32 sign, size_t reserve) +{ + struct usb_cdc_ncm_ndp16 *ndp16 = NULL; + struct usb_cdc_ncm_nth16 *nth16 = (void *)skb->data; + size_t ndpoffset = le16_to_cpu(nth16->wNdpIndex); + + /* follow the chain of NDPs, looking for a match */ + while (ndpoffset) { + ndp16 = (struct usb_cdc_ncm_ndp16 *)(skb->data + ndpoffset); + if (ndp16->dwSignature == sign) + return ndp16; + ndpoffset = le16_to_cpu(ndp16->wNextNdpIndex); + } + + /* align new NDP */ + cdc_ncm_align_tail(skb, ctx->tx_ndp_modulus, 0, ctx->tx_max); + + /* verify that there is room for the NDP and the datagram (reserve) */ + if ((ctx->tx_max - skb->len - reserve) < CDC_NCM_NDP_SIZE) + return NULL; + + /* link to it */ + if (ndp16) + ndp16->wNextNdpIndex = cpu_to_le16(skb->len); + else + nth16->wNdpIndex = cpu_to_le16(skb->len); + + /* push a new empty NDP */ + ndp16 = (struct usb_cdc_ncm_ndp16 *)memset(skb_put(skb, CDC_NCM_NDP_SIZE), 0, CDC_NCM_NDP_SIZE); + ndp16->dwSignature = sign; + ndp16->wLength = cpu_to_le16(sizeof(struct usb_cdc_ncm_ndp16) + sizeof(struct usb_cdc_ncm_dpe16)); + return ndp16; } static struct sk_buff * -cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb) +cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb, __le32 sign) { + struct usb_cdc_ncm_nth16 *nth16; + struct usb_cdc_ncm_ndp16 *ndp16; struct sk_buff *skb_out; - u32 rem; - u32 offset; - u32 last_offset; - u16 n = 0, index; + u16 n = 0, index, ndplen; u8 ready2send = 0; /* if there is a remaining skb, it gets priority */ - if (skb != NULL) + if (skb != NULL) { swap(skb, ctx->tx_rem_skb); - else + swap(sign, ctx->tx_rem_sign); + } else { ready2send = 1; - - /* - * +----------------+ - * | skb_out | - * +----------------+ - * ^ offset - * ^ last_offset - */ + } /* check if we are resuming an OUT skb */ - if (ctx->tx_curr_skb != NULL) { - /* pop variables */ - skb_out = ctx->tx_curr_skb; - offset = ctx->tx_curr_offset; - last_offset = ctx->tx_curr_last_offset; - n = ctx->tx_curr_frame_num; + skb_out = ctx->tx_curr_skb; - } else { - /* reset variables */ + /* allocate a new OUT skb */ + if (!skb_out) { skb_out = alloc_skb((ctx->tx_max + 1), GFP_ATOMIC); if (skb_out == NULL) { if (skb != NULL) { @@ -732,35 +752,21 @@ cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb) } goto exit_no_skb; } + /* fill out the initial 16-bit NTB header */ + nth16 = (struct usb_cdc_ncm_nth16 *)memset(skb_put(skb_out, sizeof(struct usb_cdc_ncm_nth16)), 0, sizeof(struct usb_cdc_ncm_nth16)); + nth16->dwSignature = cpu_to_le32(USB_CDC_NCM_NTH16_SIGN); + nth16->wHeaderLength = cpu_to_le16(sizeof(struct usb_cdc_ncm_nth16)); + nth16->wSequence = cpu_to_le16(ctx->tx_seq++); - /* make room for NTH and NDP */ - offset = ALIGN(sizeof(struct usb_cdc_ncm_nth16), - ctx->tx_ndp_modulus) + - sizeof(struct usb_cdc_ncm_ndp16) + - (ctx->tx_max_datagrams + 1) * - sizeof(struct usb_cdc_ncm_dpe16); - - /* store last valid offset before alignment */ - last_offset = offset; - /* align first Datagram offset correctly */ - offset = ALIGN(offset, ctx->tx_modulus) + ctx->tx_remainder; - /* zero buffer till the first IP datagram */ - cdc_ncm_zero_fill(skb_out->data, 0, offset, offset); - n = 0; + /* count total number of frames in this NTB */ ctx->tx_curr_frame_num = 0; } - for (; n < ctx->tx_max_datagrams; n++) { - /* check if end of transmit buffer is reached */ - if (offset >= ctx->tx_max) { - ready2send = 1; - break; - } - /* compute maximum buffer size */ - rem = ctx->tx_max - offset; - + for (n = ctx->tx_curr_frame_num; n < ctx->tx_max_datagrams; n++) { + /* send any remaining skb first */ if (skb == NULL) { skb = ctx->tx_rem_skb; + sign = ctx->tx_rem_sign; ctx->tx_rem_skb = NULL; /* check for end of skb */ @@ -768,7 +774,14 @@ cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb) break; } - if (skb->len > rem) { + /* get the appropriate NDP for this skb */ + ndp16 = cdc_ncm_ndp(ctx, skb_out, sign, skb->len + ctx->tx_modulus + ctx->tx_remainder); + + /* align beginning of next frame */ + cdc_ncm_align_tail(skb_out, ctx->tx_modulus, ctx->tx_remainder, ctx->tx_max); + + /* check if we had enough room left for both NDP and frame */ + if (!ndp16 || skb_out->len + skb->len > ctx->tx_max) { if (n == 0) { /* won't fit, MTU problem? */ dev_kfree_skb_any(skb); @@ -781,31 +794,32 @@ cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb) ctx->netdev->stats.tx_dropped++; } ctx->tx_rem_skb = skb; + ctx->tx_rem_sign = sign; skb = NULL; ready2send = 1; } break; } - memcpy(((u8 *)skb_out->data) + offset, skb->data, skb->len); - - ctx->tx_ncm.dpe16[n].wDatagramLength = cpu_to_le16(skb->len); - ctx->tx_ncm.dpe16[n].wDatagramIndex = cpu_to_le16(offset); - - /* update offset */ - offset += skb->len; - - /* store last valid offset before alignment */ - last_offset = offset; - - /* align offset correctly */ - offset = ALIGN(offset, ctx->tx_modulus) + ctx->tx_remainder; - - /* zero padding */ - cdc_ncm_zero_fill(skb_out->data, last_offset, offset, - ctx->tx_max); + /* calculate frame number withing this NDP */ + ndplen = le16_to_cpu(ndp16->wLength); + /* struct usb_cdc_ncm_dpe16 is 2 * 16bit packed */ + BUILD_BUG_ON(sizeof(struct usb_cdc_ncm_dpe16) != 1 << 2); + index = ((ndplen - sizeof(struct usb_cdc_ncm_ndp16)) >> 2) - 1; + + /* OK, add this skb */ + ndp16->dpe16[index].wDatagramLength = cpu_to_le16(skb->len); + ndp16->dpe16[index].wDatagramIndex = cpu_to_le16(skb_out->len); + ndp16->wLength = cpu_to_le16(ndplen + sizeof(struct usb_cdc_ncm_dpe16)); + memcpy(skb_put(skb_out, skb->len), skb->data, skb->len); dev_kfree_skb_any(skb); skb = NULL; + + /* send now if this NDP is full */ + if (index >= CDC_NCM_DPT_DATAGRAMS_MAX) { + ready2send = 1; + break; + } } /* free up any dangling skb */ @@ -821,16 +835,12 @@ cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb) /* wait for more frames */ /* push variables */ ctx->tx_curr_skb = skb_out; - ctx->tx_curr_offset = offset; - ctx->tx_curr_last_offset = last_offset; goto exit_no_skb; } else if ((n < ctx->tx_max_datagrams) && (ready2send == 0)) { /* wait for more frames */ /* push variables */ ctx->tx_curr_skb = skb_out; - ctx->tx_curr_offset = offset; - ctx->tx_curr_last_offset = last_offset; /* set the pending count */ if (n < CDC_NCM_RESTART_TIMER_DATAGRAM_CNT) ctx->tx_timer_pending = CDC_NCM_TIMER_PENDING_CNT; @@ -841,75 +851,24 @@ cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb) /* variables will be reset at next call */ } - /* check for overflow */ - if (last_offset > ctx->tx_max) - last_offset = ctx->tx_max; - - /* revert offset */ - offset = last_offset; - /* * If collected data size is less or equal CDC_NCM_MIN_TX_PKT bytes, * we send buffers as it is. If we get more data, it would be more * efficient for USB HS mobile device with DMA engine to receive a full * size NTB, than canceling DMA transfer and receiving a short packet. */ - if (offset > CDC_NCM_MIN_TX_PKT) - offset = ctx->tx_max; - - /* final zero padding */ - cdc_ncm_zero_fill(skb_out->data, last_offset, offset, ctx->tx_max); - - /* store last offset */ - last_offset = offset; - - if (((last_offset < ctx->tx_max) && ((last_offset % - le16_to_cpu(ctx->out_ep->desc.wMaxPacketSize)) == 0)) || - (((last_offset == ctx->tx_max) && ((ctx->tx_max % - le16_to_cpu(ctx->out_ep->desc.wMaxPacketSize)) == 0)) && - (ctx->tx_max < le32_to_cpu(ctx->ncm_parm.dwNtbOutMaxSize)))) { - /* force short packet */ - *(((u8 *)skb_out->data) + last_offset) = 0; - last_offset++; - } + if (skb_out->len > CDC_NCM_MIN_TX_PKT) + /* final zero padding */ + memset(skb_put(skb_out, ctx->tx_max - skb_out->len), 0, ctx->tx_max - skb_out->len); - /* zero the rest of the DPEs plus the last NULL entry */ - for (; n <= CDC_NCM_DPT_DATAGRAMS_MAX; n++) { - ctx->tx_ncm.dpe16[n].wDatagramLength = 0; - ctx->tx_ncm.dpe16[n].wDatagramIndex = 0; - } - - /* fill out 16-bit NTB header */ - ctx->tx_ncm.nth16.dwSignature = cpu_to_le32(USB_CDC_NCM_NTH16_SIGN); - ctx->tx_ncm.nth16.wHeaderLength = - cpu_to_le16(sizeof(ctx->tx_ncm.nth16)); - ctx->tx_ncm.nth16.wSequence = cpu_to_le16(ctx->tx_seq); - ctx->tx_ncm.nth16.wBlockLength = cpu_to_le16(last_offset); - index = ALIGN(sizeof(struct usb_cdc_ncm_nth16), ctx->tx_ndp_modulus); - ctx->tx_ncm.nth16.wNdpIndex = cpu_to_le16(index); - - memcpy(skb_out->data, &(ctx->tx_ncm.nth16), sizeof(ctx->tx_ncm.nth16)); - ctx->tx_seq++; - - /* fill out 16-bit NDP table */ - ctx->tx_ncm.ndp16.dwSignature = - cpu_to_le32(USB_CDC_NCM_NDP16_NOCRC_SIGN); - rem = sizeof(ctx->tx_ncm.ndp16) + ((ctx->tx_curr_frame_num + 1) * - sizeof(struct usb_cdc_ncm_dpe16)); - ctx->tx_ncm.ndp16.wLength = cpu_to_le16(rem); - ctx->tx_ncm.ndp16.wNextNdpIndex = 0; /* reserved */ - - memcpy(((u8 *)skb_out->data) + index, - &(ctx->tx_ncm.ndp16), - sizeof(ctx->tx_ncm.ndp16)); - - memcpy(((u8 *)skb_out->data) + index + sizeof(ctx->tx_ncm.ndp16), - &(ctx->tx_ncm.dpe16), - (ctx->tx_curr_frame_num + 1) * - sizeof(struct usb_cdc_ncm_dpe16)); + /* do we need to prevent a ZLP? */ + if (((skb_out->len % le16_to_cpu(ctx->out_ep->desc.wMaxPacketSize)) == 0) && + (skb_out->len < le32_to_cpu(ctx->ncm_parm.dwNtbOutMaxSize)) && skb_tailroom(skb_out)) + *skb_put(skb_out, 1) = 0; /* force short packet */ - /* set frame length */ - skb_put(skb_out, last_offset); + /* set final frame length */ + nth16 = (struct usb_cdc_ncm_nth16 *)skb_out->data; + nth16->wBlockLength = cpu_to_le16(skb_out->len); /* return skb */ ctx->tx_curr_skb = NULL; @@ -976,7 +935,7 @@ cdc_ncm_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags) goto error; spin_lock_bh(&ctx->mtx); - skb_out = cdc_ncm_fill_tx_frame(ctx, skb); + skb_out = cdc_ncm_fill_tx_frame(ctx, skb, cpu_to_le32(USB_CDC_NCM_NDP16_NOCRC_SIGN)); spin_unlock_bh(&ctx->mtx); return skb_out; -- cgit v1.2.3