diff options
Diffstat (limited to 'drivers/scsi/fcoe/fcoe_transport.c')
| -rw-r--r-- | drivers/scsi/fcoe/fcoe_transport.c | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/drivers/scsi/fcoe/fcoe_transport.c b/drivers/scsi/fcoe/fcoe_transport.c index e5aef5639124..745eb9a22d64 100644 --- a/drivers/scsi/fcoe/fcoe_transport.c +++ b/drivers/scsi/fcoe/fcoe_transport.c @@ -23,6 +23,7 @@ #include <linux/list.h> #include <linux/netdevice.h> #include <linux/errno.h> +#include <linux/crc32.h> #include <scsi/libfcoe.h> #include "libfcoe.h" @@ -75,6 +76,205 @@ __MODULE_PARM_TYPE(disable, "string"); MODULE_PARM_DESC(disable, " Disables fcoe on a ethernet interface."); /** + * fcoe_fc_crc() - Calculates the CRC for a given frame + * @fp: The frame to be checksumed + * + * This uses crc32() routine to calculate the CRC for a frame + * + * Return: The 32 bit CRC value + */ +u32 fcoe_fc_crc(struct fc_frame *fp) +{ + struct sk_buff *skb = fp_skb(fp); + struct skb_frag_struct *frag; + unsigned char *data; + unsigned long off, len, clen; + u32 crc; + unsigned i; + + crc = crc32(~0, skb->data, skb_headlen(skb)); + + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { + frag = &skb_shinfo(skb)->frags[i]; + off = frag->page_offset; + len = frag->size; + while (len > 0) { + clen = min(len, PAGE_SIZE - (off & ~PAGE_MASK)); + data = kmap_atomic(frag->page + (off >> PAGE_SHIFT), + KM_SKB_DATA_SOFTIRQ); + crc = crc32(crc, data + (off & ~PAGE_MASK), clen); + kunmap_atomic(data, KM_SKB_DATA_SOFTIRQ); + off += clen; + len -= clen; + } + } + return crc; +} +EXPORT_SYMBOL_GPL(fcoe_fc_crc); + +/** + * fcoe_start_io() - Start FCoE I/O + * @skb: The packet to be transmitted + * + * This routine is called from the net device to start transmitting + * FCoE packets. + * + * Returns: 0 for success + */ +int fcoe_start_io(struct sk_buff *skb) +{ + struct sk_buff *nskb; + int rc; + + nskb = skb_clone(skb, GFP_ATOMIC); + if (!nskb) + return -ENOMEM; + rc = dev_queue_xmit(nskb); + if (rc != 0) + return rc; + kfree_skb(skb); + return 0; +} +EXPORT_SYMBOL_GPL(fcoe_start_io); + + +/** + * fcoe_clean_pending_queue() - Dequeue a skb and free it + * @lport: The local port to dequeue a skb on + */ +void fcoe_clean_pending_queue(struct fc_lport *lport) +{ + struct fcoe_port *port = lport_priv(lport); + struct sk_buff *skb; + + spin_lock_bh(&port->fcoe_pending_queue.lock); + while ((skb = __skb_dequeue(&port->fcoe_pending_queue)) != NULL) { + spin_unlock_bh(&port->fcoe_pending_queue.lock); + kfree_skb(skb); + spin_lock_bh(&port->fcoe_pending_queue.lock); + } + spin_unlock_bh(&port->fcoe_pending_queue.lock); +} +EXPORT_SYMBOL_GPL(fcoe_clean_pending_queue); + +/** + * fcoe_check_wait_queue() - Attempt to clear the transmit backlog + * @lport: The local port whose backlog is to be cleared + * + * This empties the wait_queue, dequeues the head of the wait_queue queue + * and calls fcoe_start_io() for each packet. If all skb have been + * transmitted it returns the qlen. If an error occurs it restores + * wait_queue (to try again later) and returns -1. + * + * The wait_queue is used when the skb transmit fails. The failed skb + * will go in the wait_queue which will be emptied by the timer function or + * by the next skb transmit. + */ +void fcoe_check_wait_queue(struct fc_lport *lport, struct sk_buff *skb) +{ + struct fcoe_port *port = lport_priv(lport); + int rc; + + spin_lock_bh(&port->fcoe_pending_queue.lock); + + if (skb) + __skb_queue_tail(&port->fcoe_pending_queue, skb); + + if (port->fcoe_pending_queue_active) + goto out; + port->fcoe_pending_queue_active = 1; + + while (port->fcoe_pending_queue.qlen) { + /* keep qlen > 0 until fcoe_start_io succeeds */ + port->fcoe_pending_queue.qlen++; + skb = __skb_dequeue(&port->fcoe_pending_queue); + + spin_unlock_bh(&port->fcoe_pending_queue.lock); + rc = fcoe_start_io(skb); + spin_lock_bh(&port->fcoe_pending_queue.lock); + + if (rc) { + __skb_queue_head(&port->fcoe_pending_queue, skb); + /* undo temporary increment above */ + port->fcoe_pending_queue.qlen--; + break; + } + /* undo temporary increment above */ + port->fcoe_pending_queue.qlen--; + } + + if (port->fcoe_pending_queue.qlen < port->min_queue_depth) + lport->qfull = 0; + if (port->fcoe_pending_queue.qlen && !timer_pending(&port->timer)) + mod_timer(&port->timer, jiffies + 2); + port->fcoe_pending_queue_active = 0; +out: + if (port->fcoe_pending_queue.qlen > port->max_queue_depth) + lport->qfull = 1; + spin_unlock_bh(&port->fcoe_pending_queue.lock); +} +EXPORT_SYMBOL_GPL(fcoe_check_wait_queue); + +/** + * fcoe_queue_timer() - The fcoe queue timer + * @lport: The local port + * + * Calls fcoe_check_wait_queue on timeout + */ +void fcoe_queue_timer(ulong lport) +{ + fcoe_check_wait_queue((struct fc_lport *)lport, NULL); +} +EXPORT_SYMBOL_GPL(fcoe_queue_timer); + +/** + * fcoe_get_paged_crc_eof() - Allocate a page to be used for the trailer CRC + * @skb: The packet to be transmitted + * @tlen: The total length of the trailer + * @fps: The fcoe context + * + * This routine allocates a page for frame trailers. The page is re-used if + * there is enough room left on it for the current trailer. If there isn't + * enough buffer left a new page is allocated for the trailer. Reference to + * the page from this function as well as the skbs using the page fragments + * ensure that the page is freed at the appropriate time. + * + * Returns: 0 for success + */ +int fcoe_get_paged_crc_eof(struct sk_buff *skb, int tlen, + struct fcoe_percpu_s *fps) +{ + struct page *page; + + page = fps->crc_eof_page; + if (!page) { + page = alloc_page(GFP_ATOMIC); + if (!page) + return -ENOMEM; + + fps->crc_eof_page = page; + fps->crc_eof_offset = 0; + } + + get_page(page); + skb_fill_page_desc(skb, skb_shinfo(skb)->nr_frags, page, + fps->crc_eof_offset, tlen); + skb->len += tlen; + skb->data_len += tlen; + skb->truesize += tlen; + fps->crc_eof_offset += sizeof(struct fcoe_crc_eof); + + if (fps->crc_eof_offset >= PAGE_SIZE) { + fps->crc_eof_page = NULL; + fps->crc_eof_offset = 0; + put_page(page); + } + + return 0; +} +EXPORT_SYMBOL_GPL(fcoe_get_paged_crc_eof); + +/** * fcoe_transport_lookup - find an fcoe transport that matches a netdev * @netdev: The netdev to look for from all attached transports * |