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[SCSI] cxgb3i: transmit work-request fixes
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- resize the work-request credit array to be based on skb's MAX_SKB_FRAGS.
- split the skb cb into tx and rx portion
- increase the default transmit window to 128K.
- stop queueing up the outgoing pdus if transmit window is full.

Signed-off-by: Karen Xie <kxie@chelsio.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
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Karen Xie authored and James Bottomley committed Feb 22, 2009
1 parent b73a774 commit 1648b11
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Showing 2 changed files with 121 additions and 53 deletions.
146 changes: 103 additions & 43 deletions drivers/scsi/cxgb3i/cxgb3i_offload.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -23,19 +23,19 @@
#include "cxgb3i_ddp.h"

#ifdef __DEBUG_C3CN_CONN__
#define c3cn_conn_debug cxgb3i_log_info
#define c3cn_conn_debug cxgb3i_log_debug
#else
#define c3cn_conn_debug(fmt...)
#endif

#ifdef __DEBUG_C3CN_TX__
#define c3cn_tx_debug cxgb3i_log_debug
#define c3cn_tx_debug cxgb3i_log_debug
#else
#define c3cn_tx_debug(fmt...)
#endif

#ifdef __DEBUG_C3CN_RX__
#define c3cn_rx_debug cxgb3i_log_debug
#define c3cn_rx_debug cxgb3i_log_debug
#else
#define c3cn_rx_debug(fmt...)
#endif
Expand All @@ -47,9 +47,9 @@ static int cxgb3_rcv_win = 256 * 1024;
module_param(cxgb3_rcv_win, int, 0644);
MODULE_PARM_DESC(cxgb3_rcv_win, "TCP receive window in bytes (default=256KB)");

static int cxgb3_snd_win = 64 * 1024;
static int cxgb3_snd_win = 128 * 1024;
module_param(cxgb3_snd_win, int, 0644);
MODULE_PARM_DESC(cxgb3_snd_win, "TCP send window in bytes (default=64KB)");
MODULE_PARM_DESC(cxgb3_snd_win, "TCP send window in bytes (default=128KB)");

static int cxgb3_rx_credit_thres = 10 * 1024;
module_param(cxgb3_rx_credit_thres, int, 0644);
Expand Down Expand Up @@ -301,8 +301,8 @@ static void act_open_req_arp_failure(struct t3cdev *dev, struct sk_buff *skb)
static void skb_entail(struct s3_conn *c3cn, struct sk_buff *skb,
int flags)
{
CXGB3_SKB_CB(skb)->seq = c3cn->write_seq;
CXGB3_SKB_CB(skb)->flags = flags;
skb_tcp_seq(skb) = c3cn->write_seq;
skb_flags(skb) = flags;
__skb_queue_tail(&c3cn->write_queue, skb);
}

Expand Down Expand Up @@ -457,12 +457,9 @@ static unsigned int wrlen __read_mostly;
* The number of WRs needed for an skb depends on the number of fragments
* in the skb and whether it has any payload in its main body. This maps the
* length of the gather list represented by an skb into the # of necessary WRs.
*
* The max. length of an skb is controlled by the max pdu size which is ~16K.
* Also, assume the min. fragment length is the sector size (512), then add
* extra fragment counts for iscsi bhs and payload padding.
* The extra two fragments are for iscsi bhs and payload padding.
*/
#define SKB_WR_LIST_SIZE (16384/512 + 3)
#define SKB_WR_LIST_SIZE (MAX_SKB_FRAGS + 2)
static unsigned int skb_wrs[SKB_WR_LIST_SIZE] __read_mostly;

static void s3_init_wr_tab(unsigned int wr_len)
Expand All @@ -485,7 +482,7 @@ static void s3_init_wr_tab(unsigned int wr_len)

static inline void reset_wr_list(struct s3_conn *c3cn)
{
c3cn->wr_pending_head = NULL;
c3cn->wr_pending_head = c3cn->wr_pending_tail = NULL;
}

/*
Expand All @@ -496,7 +493,7 @@ static inline void reset_wr_list(struct s3_conn *c3cn)
static inline void enqueue_wr(struct s3_conn *c3cn,
struct sk_buff *skb)
{
skb_wr_data(skb) = NULL;
skb_tx_wr_next(skb) = NULL;

/*
* We want to take an extra reference since both us and the driver
Expand All @@ -509,10 +506,22 @@ static inline void enqueue_wr(struct s3_conn *c3cn,
if (!c3cn->wr_pending_head)
c3cn->wr_pending_head = skb;
else
skb_wr_data(skb) = skb;
skb_tx_wr_next(c3cn->wr_pending_tail) = skb;
c3cn->wr_pending_tail = skb;
}

static int count_pending_wrs(struct s3_conn *c3cn)
{
int n = 0;
const struct sk_buff *skb = c3cn->wr_pending_head;

while (skb) {
n += skb->csum;
skb = skb_tx_wr_next(skb);
}
return n;
}

static inline struct sk_buff *peek_wr(const struct s3_conn *c3cn)
{
return c3cn->wr_pending_head;
Expand All @@ -529,8 +538,8 @@ static inline struct sk_buff *dequeue_wr(struct s3_conn *c3cn)

if (likely(skb)) {
/* Don't bother clearing the tail */
c3cn->wr_pending_head = skb_wr_data(skb);
skb_wr_data(skb) = NULL;
c3cn->wr_pending_head = skb_tx_wr_next(skb);
skb_tx_wr_next(skb) = NULL;
}
return skb;
}
Expand All @@ -543,13 +552,14 @@ static void purge_wr_queue(struct s3_conn *c3cn)
}

static inline void make_tx_data_wr(struct s3_conn *c3cn, struct sk_buff *skb,
int len)
int len, int req_completion)
{
struct tx_data_wr *req;

skb_reset_transport_header(skb);
req = (struct tx_data_wr *)__skb_push(skb, sizeof(*req));
req->wr_hi = htonl(V_WR_OP(FW_WROPCODE_OFLD_TX_DATA));
req->wr_hi = htonl(V_WR_OP(FW_WROPCODE_OFLD_TX_DATA) |
(req_completion ? F_WR_COMPL : 0));
req->wr_lo = htonl(V_WR_TID(c3cn->tid));
req->sndseq = htonl(c3cn->snd_nxt);
/* len includes the length of any HW ULP additions */
Expand Down Expand Up @@ -592,7 +602,7 @@ static int c3cn_push_tx_frames(struct s3_conn *c3cn, int req_completion)

if (unlikely(c3cn->state == C3CN_STATE_CONNECTING ||
c3cn->state == C3CN_STATE_CLOSE_WAIT_1 ||
c3cn->state == C3CN_STATE_ABORTING)) {
c3cn->state >= C3CN_STATE_ABORTING)) {
c3cn_tx_debug("c3cn 0x%p, in closing state %u.\n",
c3cn, c3cn->state);
return 0;
Expand All @@ -615,7 +625,7 @@ static int c3cn_push_tx_frames(struct s3_conn *c3cn, int req_completion)
if (c3cn->wr_avail < wrs_needed) {
c3cn_tx_debug("c3cn 0x%p, skb len %u/%u, frag %u, "
"wr %d < %u.\n",
c3cn, skb->len, skb->datalen, frags,
c3cn, skb->len, skb->data_len, frags,
wrs_needed, c3cn->wr_avail);
break;
}
Expand All @@ -627,20 +637,24 @@ static int c3cn_push_tx_frames(struct s3_conn *c3cn, int req_completion)
c3cn->wr_unacked += wrs_needed;
enqueue_wr(c3cn, skb);

if (likely(CXGB3_SKB_CB(skb)->flags & C3CB_FLAG_NEED_HDR)) {
len += ulp_extra_len(skb);
make_tx_data_wr(c3cn, skb, len);
c3cn->snd_nxt += len;
if ((req_completion
&& c3cn->wr_unacked == wrs_needed)
|| (CXGB3_SKB_CB(skb)->flags & C3CB_FLAG_COMPL)
|| c3cn->wr_unacked >= c3cn->wr_max / 2) {
struct work_request_hdr *wr = cplhdr(skb);
c3cn_tx_debug("c3cn 0x%p, enqueue, skb len %u/%u, frag %u, "
"wr %d, left %u, unack %u.\n",
c3cn, skb->len, skb->data_len, frags,
wrs_needed, c3cn->wr_avail, c3cn->wr_unacked);


wr->wr_hi |= htonl(F_WR_COMPL);
if (likely(skb_flags(skb) & C3CB_FLAG_NEED_HDR)) {
if ((req_completion &&
c3cn->wr_unacked == wrs_needed) ||
(skb_flags(skb) & C3CB_FLAG_COMPL) ||
c3cn->wr_unacked >= c3cn->wr_max / 2) {
req_completion = 1;
c3cn->wr_unacked = 0;
}
CXGB3_SKB_CB(skb)->flags &= ~C3CB_FLAG_NEED_HDR;
len += ulp_extra_len(skb);
make_tx_data_wr(c3cn, skb, len, req_completion);
c3cn->snd_nxt += len;
skb_flags(skb) &= ~C3CB_FLAG_NEED_HDR;
}

total_size += skb->truesize;
Expand Down Expand Up @@ -735,8 +749,11 @@ static void process_act_establish(struct s3_conn *c3cn, struct sk_buff *skb)
if (unlikely(c3cn_flag(c3cn, C3CN_ACTIVE_CLOSE_NEEDED)))
/* upper layer has requested closing */
send_abort_req(c3cn);
else if (c3cn_push_tx_frames(c3cn, 1))
else {
if (skb_queue_len(&c3cn->write_queue))
c3cn_push_tx_frames(c3cn, 1);
cxgb3i_conn_tx_open(c3cn);
}
}

static int do_act_establish(struct t3cdev *cdev, struct sk_buff *skb,
Expand Down Expand Up @@ -1082,8 +1099,8 @@ static void process_rx_iscsi_hdr(struct s3_conn *c3cn, struct sk_buff *skb)
return;
}

CXGB3_SKB_CB(skb)->seq = ntohl(hdr_cpl->seq);
CXGB3_SKB_CB(skb)->flags = 0;
skb_tcp_seq(skb) = ntohl(hdr_cpl->seq);
skb_flags(skb) = 0;

skb_reset_transport_header(skb);
__skb_pull(skb, sizeof(struct cpl_iscsi_hdr));
Expand All @@ -1103,12 +1120,12 @@ static void process_rx_iscsi_hdr(struct s3_conn *c3cn, struct sk_buff *skb)
goto abort_conn;

skb_ulp_mode(skb) = ULP2_FLAG_DATA_READY;
skb_ulp_pdulen(skb) = ntohs(ddp_cpl.len);
skb_ulp_ddigest(skb) = ntohl(ddp_cpl.ulp_crc);
skb_rx_pdulen(skb) = ntohs(ddp_cpl.len);
skb_rx_ddigest(skb) = ntohl(ddp_cpl.ulp_crc);
status = ntohl(ddp_cpl.ddp_status);

c3cn_rx_debug("rx skb 0x%p, len %u, pdulen %u, ddp status 0x%x.\n",
skb, skb->len, skb_ulp_pdulen(skb), status);
skb, skb->len, skb_rx_pdulen(skb), status);

if (status & (1 << RX_DDP_STATUS_HCRC_SHIFT))
skb_ulp_mode(skb) |= ULP2_FLAG_HCRC_ERROR;
Expand All @@ -1126,7 +1143,7 @@ static void process_rx_iscsi_hdr(struct s3_conn *c3cn, struct sk_buff *skb)
} else if (status & (1 << RX_DDP_STATUS_DDP_SHIFT))
skb_ulp_mode(skb) |= ULP2_FLAG_DATA_DDPED;

c3cn->rcv_nxt = ntohl(ddp_cpl.seq) + skb_ulp_pdulen(skb);
c3cn->rcv_nxt = ntohl(ddp_cpl.seq) + skb_rx_pdulen(skb);
__pskb_trim(skb, len);
__skb_queue_tail(&c3cn->receive_queue, skb);
cxgb3i_conn_pdu_ready(c3cn);
Expand All @@ -1151,12 +1168,27 @@ static int do_iscsi_hdr(struct t3cdev *t3dev, struct sk_buff *skb, void *ctx)
* Process an acknowledgment of WR completion. Advance snd_una and send the
* next batch of work requests from the write queue.
*/
static void check_wr_invariants(struct s3_conn *c3cn)
{
int pending = count_pending_wrs(c3cn);

if (unlikely(c3cn->wr_avail + pending != c3cn->wr_max))
cxgb3i_log_error("TID %u: credit imbalance: avail %u, "
"pending %u, total should be %u\n",
c3cn->tid, c3cn->wr_avail, pending,
c3cn->wr_max);
}

static void process_wr_ack(struct s3_conn *c3cn, struct sk_buff *skb)
{
struct cpl_wr_ack *hdr = cplhdr(skb);
unsigned int credits = ntohs(hdr->credits);
u32 snd_una = ntohl(hdr->snd_una);

c3cn_tx_debug("%u WR credits, avail %u, unack %u, TID %u, state %u.\n",
credits, c3cn->wr_avail, c3cn->wr_unacked,
c3cn->tid, c3cn->state);

c3cn->wr_avail += credits;
if (c3cn->wr_unacked > c3cn->wr_max - c3cn->wr_avail)
c3cn->wr_unacked = c3cn->wr_max - c3cn->wr_avail;
Expand All @@ -1171,6 +1203,17 @@ static void process_wr_ack(struct s3_conn *c3cn, struct sk_buff *skb)
break;
}
if (unlikely(credits < p->csum)) {
struct tx_data_wr *w = cplhdr(p);
cxgb3i_log_error("TID %u got %u WR credits need %u, "
"len %u, main body %u, frags %u, "
"seq # %u, ACK una %u, ACK nxt %u, "
"WR_AVAIL %u, WRs pending %u\n",
c3cn->tid, credits, p->csum, p->len,
p->len - p->data_len,
skb_shinfo(p)->nr_frags,
ntohl(w->sndseq), snd_una,
ntohl(hdr->snd_nxt), c3cn->wr_avail,
count_pending_wrs(c3cn) - credits);
p->csum -= credits;
break;
} else {
Expand All @@ -1180,15 +1223,24 @@ static void process_wr_ack(struct s3_conn *c3cn, struct sk_buff *skb)
}
}

if (unlikely(before(snd_una, c3cn->snd_una)))
check_wr_invariants(c3cn);

if (unlikely(before(snd_una, c3cn->snd_una))) {
cxgb3i_log_error("TID %u, unexpected sequence # %u in WR_ACK "
"snd_una %u\n",
c3cn->tid, snd_una, c3cn->snd_una);
goto out_free;
}

if (c3cn->snd_una != snd_una) {
c3cn->snd_una = snd_una;
dst_confirm(c3cn->dst_cache);
}

if (skb_queue_len(&c3cn->write_queue) && c3cn_push_tx_frames(c3cn, 0))
if (skb_queue_len(&c3cn->write_queue)) {
if (c3cn_push_tx_frames(c3cn, 0))
cxgb3i_conn_tx_open(c3cn);
} else
cxgb3i_conn_tx_open(c3cn);
out_free:
__kfree_skb(skb);
Expand Down Expand Up @@ -1452,7 +1504,7 @@ static void init_offload_conn(struct s3_conn *c3cn,
struct dst_entry *dst)
{
BUG_ON(c3cn->cdev != cdev);
c3cn->wr_max = c3cn->wr_avail = T3C_DATA(cdev)->max_wrs;
c3cn->wr_max = c3cn->wr_avail = T3C_DATA(cdev)->max_wrs - 1;
c3cn->wr_unacked = 0;
c3cn->mss_idx = select_mss(c3cn, dst_mtu(dst));

Expand Down Expand Up @@ -1671,9 +1723,17 @@ int cxgb3i_c3cn_send_pdus(struct s3_conn *c3cn, struct sk_buff *skb)
goto out_err;
}

err = -EPIPE;
if (c3cn->err) {
c3cn_tx_debug("c3cn 0x%p, err %d.\n", c3cn, c3cn->err);
err = -EPIPE;
goto out_err;
}

if (c3cn->write_seq - c3cn->snd_una >= cxgb3_snd_win) {
c3cn_tx_debug("c3cn 0x%p, snd %u - %u > %u.\n",
c3cn, c3cn->write_seq, c3cn->snd_una,
cxgb3_snd_win);
err = -EAGAIN;
goto out_err;
}

Expand Down
28 changes: 18 additions & 10 deletions drivers/scsi/cxgb3i/cxgb3i_offload.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -178,25 +178,33 @@ void cxgb3i_c3cn_release(struct s3_conn *);
* @flag: see C3CB_FLAG_* below
* @ulp_mode: ULP mode/submode of sk_buff
* @seq: tcp sequence number
* @ddigest: pdu data digest
* @pdulen: recovered pdu length
* @wr_data: scratch area for tx wr
*/
struct cxgb3_skb_rx_cb {
__u32 ddigest; /* data digest */
__u32 pdulen; /* recovered pdu length */
};

struct cxgb3_skb_tx_cb {
struct sk_buff *wr_next; /* next wr */
};

struct cxgb3_skb_cb {
__u8 flags;
__u8 ulp_mode;
__u32 seq;
__u32 ddigest;
__u32 pdulen;
struct sk_buff *wr_data;
union {
struct cxgb3_skb_rx_cb rx;
struct cxgb3_skb_tx_cb tx;
};
};

#define CXGB3_SKB_CB(skb) ((struct cxgb3_skb_cb *)&((skb)->cb[0]))

#define skb_flags(skb) (CXGB3_SKB_CB(skb)->flags)
#define skb_ulp_mode(skb) (CXGB3_SKB_CB(skb)->ulp_mode)
#define skb_ulp_ddigest(skb) (CXGB3_SKB_CB(skb)->ddigest)
#define skb_ulp_pdulen(skb) (CXGB3_SKB_CB(skb)->pdulen)
#define skb_wr_data(skb) (CXGB3_SKB_CB(skb)->wr_data)
#define skb_tcp_seq(skb) (CXGB3_SKB_CB(skb)->seq)
#define skb_rx_ddigest(skb) (CXGB3_SKB_CB(skb)->rx.ddigest)
#define skb_rx_pdulen(skb) (CXGB3_SKB_CB(skb)->rx.pdulen)
#define skb_tx_wr_next(skb) (CXGB3_SKB_CB(skb)->tx.wr_next)

enum c3cb_flags {
C3CB_FLAG_NEED_HDR = 1 << 0, /* packet needs a TX_DATA_WR header */
Expand Down

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