ionic: use index not pointer for queue tracking

Use index counters rather than pointers for tracking head
and tail in the queues to save a little memory and to perhaps
slightly faster queue processing.

Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_debugfs.c b/drivers/net/ethernet/pensando/ionic/ionic_debugfs.c
index e12dbe4ea73d90315532fcac10280a81bba454fb..683bbbf75115feab154602457104697668687d1b 100644 (file)
--- a/drivers/net/ethernet/pensando/ionic/ionic_debugfs.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_debugfs.c
@@ -76,7 +76,7 @@ static int q_tail_show(struct seq_file *seq, void *v)
 {
        struct ionic_queue *q = seq->private;
 
-       seq_printf(seq, "%d\n", q->tail->index);
+       seq_printf(seq, "%d\n", q->tail_idx);
 
        return 0;
 }
@@ -86,7 +86,7 @@ static int q_head_show(struct seq_file *seq, void *v)
 {
        struct ionic_queue *q = seq->private;
 
-       seq_printf(seq, "%d\n", q->head->index);
+       seq_printf(seq, "%d\n", q->head_idx);
 
        return 0;
 }
@@ -96,7 +96,7 @@ static int cq_tail_show(struct seq_file *seq, void *v)
 {
        struct ionic_cq *cq = seq->private;
 
-       seq_printf(seq, "%d\n", cq->tail->index);
+       seq_printf(seq, "%d\n", cq->tail_idx);
 
        return 0;
 }

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_dev.c b/drivers/net/ethernet/pensando/ionic/ionic_dev.c
index 25cf376f3b40bcfe77e305e2fc3dc36ca651fbc2..3645673b4b1862f89b67cca624b44afc36e81a62 100644 (file)
--- a/drivers/net/ethernet/pensando/ionic/ionic_dev.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_dev.c
@@ -482,7 +482,7 @@ int ionic_cq_init(struct ionic_lif *lif, struct ionic_cq *cq,
        cq->bound_intr = intr;
        cq->num_descs = num_descs;
        cq->desc_size = desc_size;
-       cq->tail = cq->info;
+       cq->tail_idx = 0;
        cq->done_color = 1;
 
        cur = cq->info;
@@ -522,15 +522,18 @@ unsigned int ionic_cq_service(struct ionic_cq *cq, unsigned int work_to_do,
                              ionic_cq_cb cb, ionic_cq_done_cb done_cb,
                              void *done_arg)
 {
+       struct ionic_cq_info *cq_info;
        unsigned int work_done = 0;
 
        if (work_to_do == 0)
                return 0;
 
-       while (cb(cq, cq->tail)) {
-               if (cq->tail->last)
+       cq_info = &cq->info[cq->tail_idx];
+       while (cb(cq, cq_info)) {
+               if (cq->tail_idx == cq->num_descs - 1)
                        cq->done_color = !cq->done_color;
-               cq->tail = cq->tail->next;
+               cq->tail_idx = (cq->tail_idx + 1) & (cq->num_descs - 1);
+               cq_info = &cq->info[cq->tail_idx];
                DEBUG_STATS_CQE_CNT(cq);
 
                if (++work_done >= work_to_do)
@@ -565,8 +568,8 @@ int ionic_q_init(struct ionic_lif *lif, struct ionic_dev *idev,
        q->num_descs = num_descs;
        q->desc_size = desc_size;
        q->sg_desc_size = sg_desc_size;
-       q->tail = q->info;
-       q->head = q->tail;
+       q->tail_idx = 0;
+       q->head_idx = 0;
        q->pid = pid;
 
        snprintf(q->name, sizeof(q->name), "L%d-%s%u", lif->index, name, index);
@@ -614,19 +617,22 @@ void ionic_q_post(struct ionic_queue *q, bool ring_doorbell, ionic_desc_cb cb,
                  void *cb_arg)
 {
        struct device *dev = q->lif->ionic->dev;
+       struct ionic_desc_info *desc_info;
        struct ionic_lif *lif = q->lif;
 
-       q->head->cb = cb;
-       q->head->cb_arg = cb_arg;
-       q->head = q->head->next;
+       desc_info = &q->info[q->head_idx];
+       desc_info->cb = cb;
+       desc_info->cb_arg = cb_arg;
+
+       q->head_idx = (q->head_idx + 1) & (q->num_descs - 1);
 
        dev_dbg(dev, "lif=%d qname=%s qid=%d qtype=%d p_index=%d ringdb=%d\n",
                q->lif->index, q->name, q->hw_type, q->hw_index,
-               q->head->index, ring_doorbell);
+               q->head_idx, ring_doorbell);
 
        if (ring_doorbell)
                ionic_dbell_ring(lif->kern_dbpage, q->hw_type,
-                                q->dbval | q->head->index);
+                                q->dbval | q->head_idx);
 }
 
 static bool ionic_q_is_posted(struct ionic_queue *q, unsigned int pos)
@@ -634,8 +640,8 @@ static bool ionic_q_is_posted(struct ionic_queue *q, unsigned int pos)
        unsigned int mask, tail, head;
 
        mask = q->num_descs - 1;
-       tail = q->tail->index;
-       head = q->head->index;
+       tail = q->tail_idx;
+       head = q->head_idx;
 
        return ((pos - tail) & mask) < ((head - tail) & mask);
 }
@@ -648,18 +654,18 @@ void ionic_q_service(struct ionic_queue *q, struct ionic_cq_info *cq_info,
        void *cb_arg;
 
        /* check for empty queue */
-       if (q->tail->index == q->head->index)
+       if (q->tail_idx == q->head_idx)
                return;
 
        /* stop index must be for a descriptor that is not yet completed */
        if (unlikely(!ionic_q_is_posted(q, stop_index)))
                dev_err(q->lif->ionic->dev,
                        "ionic stop is not posted %s stop %u tail %u head %u\n",
-                       q->name, stop_index, q->tail->index, q->head->index);
+                       q->name, stop_index, q->tail_idx, q->head_idx);
 
        do {
-               desc_info = q->tail;
-               q->tail = desc_info->next;
+               desc_info = &q->info[q->tail_idx];
+               q->tail_idx = (q->tail_idx + 1) & (q->num_descs - 1);
 
                cb = desc_info->cb;
                cb_arg = desc_info->cb_arg;

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_dev.h b/drivers/net/ethernet/pensando/ionic/ionic_dev.h
index d5cba502abca0f5b7153960cbfd2c1e7369f8846..9e2ac2b8a0821d2d349b33e440be2e0fadd21574 100644 (file)
--- a/drivers/net/ethernet/pensando/ionic/ionic_dev.h
+++ b/drivers/net/ethernet/pensando/ionic/ionic_dev.h
@@ -149,7 +149,13 @@ struct ionic_dev {
 };
 
 struct ionic_cq_info {
-       void *cq_desc;
+       union {
+               void *cq_desc;
+               struct ionic_txq_comp *txcq;
+               struct ionic_rxq_comp *rxcq;
+               struct ionic_admin_comp *admincq;
+               struct ionic_notifyq_event *notifyq;
+       };
        struct ionic_cq_info *next;
        unsigned int index;
        bool last;
@@ -169,8 +175,17 @@ struct ionic_page_info {
 };
 
 struct ionic_desc_info {
-       void *desc;
-       void *sg_desc;
+       union {
+               void *desc;
+               struct ionic_txq_desc *txq_desc;
+               struct ionic_rxq_desc *rxq_desc;
+               struct ionic_admin_cmd *adminq_desc;
+       };
+       union {
+               void *sg_desc;
+               struct ionic_txq_sg_desc *txq_sg_desc;
+               struct ionic_rxq_sg_desc *rxq_sgl_desc;
+       };
        struct ionic_desc_info *next;
        unsigned int index;
        unsigned int left;
@@ -183,22 +198,32 @@ struct ionic_desc_info {
 #define IONIC_QUEUE_NAME_MAX_SZ                32
 
 struct ionic_queue {
+       struct device *dev;
        u64 dbell_count;
        u64 drop;
        u64 stop;
        u64 wake;
        struct ionic_lif *lif;
        struct ionic_desc_info *info;
-       struct ionic_desc_info *tail;
-       struct ionic_desc_info *head;
        struct ionic_dev *idev;
+       u16 head_idx;
+       u16 tail_idx;
        unsigned int index;
        unsigned int type;
        unsigned int hw_index;
        unsigned int hw_type;
        u64 dbval;
-       void *base;
-       void *sg_base;
+       union {
+               void *base;
+               struct ionic_txq_desc *txq;
+               struct ionic_rxq_desc *rxq;
+               struct ionic_admin_cmd *adminq;
+       };
+       union {
+               void *sg_base;
+               struct ionic_txq_sg_desc *txq_sgl;
+               struct ionic_rxq_sg_desc *rxq_sgl;
+       };
        dma_addr_t base_pa;
        dma_addr_t sg_base_pa;
        unsigned int num_descs;
@@ -225,9 +250,9 @@ struct ionic_cq {
        dma_addr_t base_pa;
        struct ionic_lif *lif;
        struct ionic_cq_info *info;
-       struct ionic_cq_info *tail;
        struct ionic_queue *bound_q;
        struct ionic_intr_info *bound_intr;
+       u16 tail_idx;
        bool done_color;
        unsigned int num_descs;
        u64 compl_count;
@@ -246,12 +271,12 @@ static inline void ionic_intr_init(struct ionic_dev *idev,
 
 static inline unsigned int ionic_q_space_avail(struct ionic_queue *q)
 {
-       unsigned int avail = q->tail->index;
+       unsigned int avail = q->tail_idx;
 
-       if (q->head->index >= avail)
-               avail += q->head->left - 1;
+       if (q->head_idx >= avail)
+               avail += q->num_descs - q->head_idx - 1;
        else
-               avail -= q->head->index + 1;
+               avail -= q->head_idx + 1;
 
        return avail;
 }

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_lif.c b/drivers/net/ethernet/pensando/ionic/ionic_lif.c
index c63d5dc8fa23cb11f7620139796f204c574a2b80..2637eb83ae1fbfbc01347848bae610064cc52def 100644 (file)
--- a/drivers/net/ethernet/pensando/ionic/ionic_lif.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_lif.c
@@ -632,9 +632,9 @@ static int ionic_lif_txq_init(struct ionic_lif *lif, struct ionic_qcq *qcq)
        dev_dbg(dev, "txq_init.ver %d\n", ctx.cmd.q_init.ver);
        dev_dbg(dev, "txq_init.intr_index %d\n", ctx.cmd.q_init.intr_index);
 
-       q->tail = q->info;
-       q->head = q->tail;
-       cq->tail = cq->info;
+       q->tail_idx = 0;
+       q->head_idx = 0;
+       cq->tail_idx = 0;
 
        err = ionic_adminq_post_wait(lif, &ctx);
        if (err)
@@ -689,9 +689,9 @@ static int ionic_lif_rxq_init(struct ionic_lif *lif, struct ionic_qcq *qcq)
        dev_dbg(dev, "rxq_init.ver %d\n", ctx.cmd.q_init.ver);
        dev_dbg(dev, "rxq_init.intr_index %d\n", ctx.cmd.q_init.intr_index);
 
-       q->tail = q->info;
-       q->head = q->tail;
-       cq->tail = cq->info;
+       q->tail_idx = 0;
+       q->head_idx = 0;
+       cq->tail_idx = 0;
 
        err = ionic_adminq_post_wait(lif, &ctx);
        if (err)

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_lif.h b/drivers/net/ethernet/pensando/ionic/ionic_lif.h
index aa7c1a8cbefc7752fd6ff4c7bab152da94f13c69..b8f774b1db3a8c0cedb6ee53e814d6d42d9c05fb 100644 (file)
--- a/drivers/net/ethernet/pensando/ionic/ionic_lif.h
+++ b/drivers/net/ethernet/pensando/ionic/ionic_lif.h
@@ -244,14 +244,15 @@ int ionic_lif_rss_config(struct ionic_lif *lif, u16 types,
 
 int ionic_reset_queues(struct ionic_lif *lif, ionic_reset_cb cb, void *arg);
 
-static inline void debug_stats_txq_post(struct ionic_queue *q,
-                                       struct ionic_txq_desc *desc, bool dbell)
+static inline void debug_stats_txq_post(struct ionic_queue *q, bool dbell)
 {
-       u8 num_sg_elems = ((le64_to_cpu(desc->cmd) >> IONIC_TXQ_DESC_NSGE_SHIFT)
-                                               & IONIC_TXQ_DESC_NSGE_MASK);
+       struct ionic_txq_desc *desc = &q->txq[q->head_idx];
+       u8 num_sg_elems;
 
        q->dbell_count += dbell;
 
+       num_sg_elems = ((le64_to_cpu(desc->cmd) >> IONIC_TXQ_DESC_NSGE_SHIFT)
+                                               & IONIC_TXQ_DESC_NSGE_MASK);
        if (num_sg_elems > (IONIC_MAX_NUM_SG_CNTR - 1))
                num_sg_elems = IONIC_MAX_NUM_SG_CNTR - 1;
 
@@ -272,8 +273,7 @@ static inline void debug_stats_napi_poll(struct ionic_qcq *qcq,
 #define DEBUG_STATS_CQE_CNT(cq)                ((cq)->compl_count++)
 #define DEBUG_STATS_RX_BUFF_CNT(q)     ((q)->lif->rxqstats[q->index].buffers_posted++)
 #define DEBUG_STATS_INTR_REARM(intr)   ((intr)->rearm_count++)
-#define DEBUG_STATS_TXQ_POST(q, txdesc, dbell) \
-       debug_stats_txq_post(q, txdesc, dbell)
+#define DEBUG_STATS_TXQ_POST(q, dbell)  debug_stats_txq_post(q, dbell)
 #define DEBUG_STATS_NAPI_POLL(qcq, work_done) \
        debug_stats_napi_poll(qcq, work_done)
 

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_main.c b/drivers/net/ethernet/pensando/ionic/ionic_main.c
index df5b9bcc3aba28a074510ddcf49c44248a679d31..2b72a51be1d080ab97d84fde9cb2dbf322114a3f 100644 (file)
--- a/drivers/net/ethernet/pensando/ionic/ionic_main.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_main.c
@@ -181,15 +181,17 @@ static const char *ionic_opcode_to_str(enum ionic_cmd_opcode opcode)
 
 static void ionic_adminq_flush(struct ionic_lif *lif)
 {
-       struct ionic_queue *adminq = &lif->adminqcq->q;
+       struct ionic_queue *q = &lif->adminqcq->q;
+       struct ionic_desc_info *desc_info;
 
        spin_lock(&lif->adminq_lock);
 
-       while (adminq->tail != adminq->head) {
-               memset(adminq->tail->desc, 0, sizeof(union ionic_adminq_cmd));
-               adminq->tail->cb = NULL;
-               adminq->tail->cb_arg = NULL;
-               adminq->tail = adminq->tail->next;
+       while (q->tail_idx != q->head_idx) {
+               desc_info = &q->info[q->tail_idx];
+               memset(desc_info->desc, 0, sizeof(union ionic_adminq_cmd));
+               desc_info->cb = NULL;
+               desc_info->cb_arg = NULL;
+               q->tail_idx = (q->tail_idx + 1) & (q->num_descs - 1);
        }
        spin_unlock(&lif->adminq_lock);
 }
@@ -245,7 +247,8 @@ static void ionic_adminq_cb(struct ionic_queue *q,
 
 static int ionic_adminq_post(struct ionic_lif *lif, struct ionic_admin_ctx *ctx)
 {
-       struct ionic_queue *adminq;
+       struct ionic_desc_info *desc_info;
+       struct ionic_queue *q;
        int err = 0;
 
        WARN_ON(in_interrupt());
@@ -253,10 +256,10 @@ static int ionic_adminq_post(struct ionic_lif *lif, struct ionic_admin_ctx *ctx)
        if (!lif->adminqcq)
                return -EIO;
 
-       adminq = &lif->adminqcq->q;
+       q = &lif->adminqcq->q;
 
        spin_lock(&lif->adminq_lock);
-       if (!ionic_q_has_space(adminq, 1)) {
+       if (!ionic_q_has_space(q, 1)) {
                err = -ENOSPC;
                goto err_out;
        }
@@ -265,13 +268,14 @@ static int ionic_adminq_post(struct ionic_lif *lif, struct ionic_admin_ctx *ctx)
        if (err)
                goto err_out;
 
-       memcpy(adminq->head->desc, &ctx->cmd, sizeof(ctx->cmd));
+       desc_info = &q->info[q->head_idx];
+       memcpy(desc_info->desc, &ctx->cmd, sizeof(ctx->cmd));
 
        dev_dbg(&lif->netdev->dev, "post admin queue command:\n");
        dynamic_hex_dump("cmd ", DUMP_PREFIX_OFFSET, 16, 1,
                         &ctx->cmd, sizeof(ctx->cmd), true);
 
-       ionic_q_post(adminq, true, ionic_adminq_cb, ctx);
+       ionic_q_post(q, true, ionic_adminq_cb, ctx);
 
 err_out:
        spin_unlock(&lif->adminq_lock);

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
index 220e132164e236ea203b6c8dcfb19afc6d054eff..c3291decd4c381abbe5361e4f33af90d24ce22d9 100644 (file)
--- a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
@@ -22,7 +22,7 @@ static bool ionic_tx_service(struct ionic_cq *cq, struct ionic_cq_info *cq_info)
 static inline void ionic_txq_post(struct ionic_queue *q, bool ring_dbell,
                                  ionic_desc_cb cb_func, void *cb_arg)
 {
-       DEBUG_STATS_TXQ_POST(q, q->head->desc, ring_dbell);
+       DEBUG_STATS_TXQ_POST(q, ring_dbell);
 
        ionic_q_post(q, ring_dbell, cb_func, cb_arg);
 }
@@ -235,14 +235,14 @@ static bool ionic_rx_service(struct ionic_cq *cq, struct ionic_cq_info *cq_info)
                return false;
 
        /* check for empty queue */
-       if (q->tail->index == q->head->index)
+       if (q->tail_idx == q->head_idx)
                return false;
 
-       desc_info = q->tail;
+       desc_info = &q->info[q->tail_idx];
        if (desc_info->index != le16_to_cpu(comp->comp_index))
                return false;
 
-       q->tail = desc_info->next;
+       q->tail_idx = (q->tail_idx + 1) & (q->num_descs - 1);
 
        /* clean the related q entry, only one per qc completion */
        ionic_rx_clean(q, desc_info, cq_info, desc_info->cb_arg);
@@ -338,7 +338,7 @@ void ionic_rx_fill(struct ionic_queue *q)
 
        for (i = ionic_q_space_avail(q); i; i--) {
                remain_len = len;
-               desc_info = q->head;
+               desc_info = &q->info[q->head_idx];
                desc = desc_info->desc;
                sg_desc = desc_info->sg_desc;
                page_info = &desc_info->pages[0];
@@ -387,7 +387,7 @@ void ionic_rx_fill(struct ionic_queue *q)
        }
 
        ionic_dbell_ring(q->lif->kern_dbpage, q->hw_type,
-                        q->dbval | q->head->index);
+                        q->dbval | q->head_idx);
 }
 
 static void ionic_rx_fill_cb(void *arg)
@@ -397,25 +397,29 @@ static void ionic_rx_fill_cb(void *arg)
 
 void ionic_rx_empty(struct ionic_queue *q)
 {
-       struct ionic_desc_info *cur;
+       struct ionic_desc_info *desc_info;
        struct ionic_rxq_desc *desc;
        unsigned int i;
+       u16 idx;
 
-       for (cur = q->tail; cur != q->head; cur = cur->next) {
-               desc = cur->desc;
+       idx = q->tail_idx;
+       while (idx != q->head_idx) {
+               desc_info = &q->info[idx];
+               desc = desc_info->desc;
                desc->addr = 0;
                desc->len = 0;
 
-               for (i = 0; i < cur->npages; i++) {
-                       if (likely(cur->pages[i].page)) {
-                               ionic_rx_page_free(q, cur->pages[i].page,
-                                                  cur->pages[i].dma_addr);
-                               cur->pages[i].page = NULL;
-                               cur->pages[i].dma_addr = 0;
+               for (i = 0; i < desc_info->npages; i++) {
+                       if (likely(desc_info->pages[i].page)) {
+                               ionic_rx_page_free(q, desc_info->pages[i].page,
+                                                  desc_info->pages[i].dma_addr);
+                               desc_info->pages[i].page = NULL;
+                               desc_info->pages[i].dma_addr = 0;
                        }
                }
 
-               cur->cb_arg = NULL;
+               desc_info->cb_arg = NULL;
+               idx = (idx + 1) & (q->num_descs - 1);
        }
 }
 
@@ -630,9 +634,9 @@ static bool ionic_tx_service(struct ionic_cq *cq, struct ionic_cq_info *cq_info)
         * several q entries completed for each cq completion
         */
        do {
-               desc_info = q->tail;
-               q->tail = desc_info->next;
-               ionic_tx_clean(q, desc_info, cq->tail, desc_info->cb_arg);
+               desc_info = &q->info[q->tail_idx];
+               q->tail_idx = (q->tail_idx + 1) & (q->num_descs - 1);
+               ionic_tx_clean(q, desc_info, cq_info, desc_info->cb_arg);
                desc_info->cb = NULL;
                desc_info->cb_arg = NULL;
        } while (desc_info->index != le16_to_cpu(comp->comp_index));
@@ -658,9 +662,9 @@ void ionic_tx_empty(struct ionic_queue *q)
        int done = 0;
 
        /* walk the not completed tx entries, if any */
-       while (q->head != q->tail) {
-               desc_info = q->tail;
-               q->tail = desc_info->next;
+       while (q->head_idx != q->tail_idx) {
+               desc_info = &q->info[q->tail_idx];
+               q->tail_idx = (q->tail_idx + 1) & (q->num_descs - 1);
                ionic_tx_clean(q, desc_info, NULL, desc_info->cb_arg);
                desc_info->cb = NULL;
                desc_info->cb_arg = NULL;
@@ -748,8 +752,8 @@ static void ionic_tx_tso_post(struct ionic_queue *q, struct ionic_txq_desc *desc
 static struct ionic_txq_desc *ionic_tx_tso_next(struct ionic_queue *q,
                                                struct ionic_txq_sg_elem **elem)
 {
-       struct ionic_txq_sg_desc *sg_desc = q->head->sg_desc;
-       struct ionic_txq_desc *desc = q->head->desc;
+       struct ionic_txq_sg_desc *sg_desc = q->info[q->head_idx].txq_sg_desc;
+       struct ionic_txq_desc *desc = q->info[q->head_idx].txq_desc;
 
        *elem = sg_desc->elems;
        return desc;
@@ -758,13 +762,13 @@ static struct ionic_txq_desc *ionic_tx_tso_next(struct ionic_queue *q,
 static int ionic_tx_tso(struct ionic_queue *q, struct sk_buff *skb)
 {
        struct ionic_tx_stats *stats = q_to_tx_stats(q);
-       struct ionic_desc_info *abort = q->head;
+       struct ionic_desc_info *rewind_desc_info;
        struct device *dev = q->lif->ionic->dev;
-       struct ionic_desc_info *rewind = abort;
        struct ionic_txq_sg_elem *elem;
        struct ionic_txq_desc *desc;
        unsigned int frag_left = 0;
        unsigned int offset = 0;
+       u16 abort = q->head_idx;
        unsigned int len_left;
        dma_addr_t desc_addr;
        unsigned int hdrlen;
@@ -772,6 +776,7 @@ static int ionic_tx_tso(struct ionic_queue *q, struct sk_buff *skb)
        unsigned int seglen;
        u64 total_bytes = 0;
        u64 total_pkts = 0;
+       u16 rewind = abort;
        unsigned int left;
        unsigned int len;
        unsigned int mss;
@@ -916,19 +921,20 @@ static int ionic_tx_tso(struct ionic_queue *q, struct sk_buff *skb)
        return 0;
 
 err_out_abort:
-       while (rewind->desc != q->head->desc) {
-               ionic_tx_clean(q, rewind, NULL, NULL);
-               rewind = rewind->next;
+       while (rewind != q->head_idx) {
+               rewind_desc_info = &q->info[rewind];
+               ionic_tx_clean(q, rewind_desc_info, NULL, NULL);
+               rewind = (rewind + 1) & (q->num_descs - 1);
        }
-       q->head = abort;
+       q->head_idx = abort;
 
        return -ENOMEM;
 }
 
 static int ionic_tx_calc_csum(struct ionic_queue *q, struct sk_buff *skb)
 {
+       struct ionic_txq_desc *desc = q->info[q->head_idx].txq_desc;
        struct ionic_tx_stats *stats = q_to_tx_stats(q);
-       struct ionic_txq_desc *desc = q->head->desc;
        struct device *dev = q->lif->ionic->dev;
        dma_addr_t dma_addr;
        bool has_vlan;
@@ -967,8 +973,8 @@ static int ionic_tx_calc_csum(struct ionic_queue *q, struct sk_buff *skb)
 
 static int ionic_tx_calc_no_csum(struct ionic_queue *q, struct sk_buff *skb)
 {
+       struct ionic_txq_desc *desc = q->info[q->head_idx].txq_desc;
        struct ionic_tx_stats *stats = q_to_tx_stats(q);
-       struct ionic_txq_desc *desc = q->head->desc;
        struct device *dev = q->lif->ionic->dev;
        dma_addr_t dma_addr;
        bool has_vlan;
@@ -1002,7 +1008,7 @@ static int ionic_tx_calc_no_csum(struct ionic_queue *q, struct sk_buff *skb)
 
 static int ionic_tx_skb_frags(struct ionic_queue *q, struct sk_buff *skb)
 {
-       struct ionic_txq_sg_desc *sg_desc = q->head->sg_desc;
+       struct ionic_txq_sg_desc *sg_desc = q->info[q->head_idx].txq_sg_desc;
        unsigned int len_left = skb->len - skb_headlen(skb);
        struct ionic_txq_sg_elem *elem = sg_desc->elems;
        struct ionic_tx_stats *stats = q_to_tx_stats(q);