net: octeontx2: Fix the confusion in buffer alloc failure path

Pavel pointed that the return of dma_addr_t in
otx2_alloc_rbuf/__otx2_alloc_rbuf() seem suspicious because a negative
error code may be returned in some cases. For a dma_addr_t, the error
code such as -ENOMEM does seem a valid value, so we can't judge if the
buffer allocation fail or not based on that value. Add a parameter for
otx2_alloc_rbuf/__otx2_alloc_rbuf() to store the dma address and make
the return value to indicate if the buffer allocation really fail or
not.

Reported-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Tested-by: Subbaraya Sundeep <sbhatta@marvell.com>
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
index cbd68fa..70a91d8 100644 (file)
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
@@ -483,33 +483,34 @@ void otx2_config_irq_coalescing(struct otx2_nic *pfvf, int qidx)
                     (pfvf->hw.cq_ecount_wait - 1));
 }
 
-dma_addr_t __otx2_alloc_rbuf(struct otx2_nic *pfvf, struct otx2_pool *pool)
+int __otx2_alloc_rbuf(struct otx2_nic *pfvf, struct otx2_pool *pool,
+                     dma_addr_t *dma)
 {
-       dma_addr_t iova;
        u8 *buf;
 
        buf = napi_alloc_frag_align(pool->rbsize, OTX2_ALIGN);
        if (unlikely(!buf))
                return -ENOMEM;
 
-       iova = dma_map_single_attrs(pfvf->dev, buf, pool->rbsize,
+       *dma = dma_map_single_attrs(pfvf->dev, buf, pool->rbsize,
                                    DMA_FROM_DEVICE, DMA_ATTR_SKIP_CPU_SYNC);
-       if (unlikely(dma_mapping_error(pfvf->dev, iova))) {
+       if (unlikely(dma_mapping_error(pfvf->dev, *dma))) {
                page_frag_free(buf);
                return -ENOMEM;
        }
 
-       return iova;
+       return 0;
 }
 
-static dma_addr_t otx2_alloc_rbuf(struct otx2_nic *pfvf, struct otx2_pool *pool)
+static int otx2_alloc_rbuf(struct otx2_nic *pfvf, struct otx2_pool *pool,
+                          dma_addr_t *dma)
 {
-       dma_addr_t addr;
+       int ret;
 
        local_bh_disable();
-       addr = __otx2_alloc_rbuf(pfvf, pool);
+       ret = __otx2_alloc_rbuf(pfvf, pool, dma);
        local_bh_enable();
-       return addr;
+       return ret;
 }
 
 void otx2_tx_timeout(struct net_device *netdev, unsigned int txq)
@@ -903,7 +904,7 @@ static void otx2_pool_refill_task(struct work_struct *work)
        struct refill_work *wrk;
        int qidx, free_ptrs = 0;
        struct otx2_nic *pfvf;
-       s64 bufptr;
+       dma_addr_t bufptr;
 
        wrk = container_of(work, struct refill_work, pool_refill_work.work);
        pfvf = wrk->pf;
@@ -913,8 +914,7 @@ static void otx2_pool_refill_task(struct work_struct *work)
        free_ptrs = cq->pool_ptrs;
 
        while (cq->pool_ptrs) {
-               bufptr = otx2_alloc_rbuf(pfvf, rbpool);
-               if (bufptr <= 0) {
+               if (otx2_alloc_rbuf(pfvf, rbpool, &bufptr)) {
                        /* Schedule a WQ if we fails to free atleast half of the
                         * pointers else enable napi for this RQ.
                         */
@@ -1213,8 +1213,8 @@ int otx2_sq_aura_pool_init(struct otx2_nic *pfvf)
        struct otx2_hw *hw = &pfvf->hw;
        struct otx2_snd_queue *sq;
        struct otx2_pool *pool;
+       dma_addr_t bufptr;
        int err, ptr;
-       s64 bufptr;
 
        /* Calculate number of SQBs needed.
         *
@@ -1259,9 +1259,8 @@ int otx2_sq_aura_pool_init(struct otx2_nic *pfvf)
                        return -ENOMEM;
 
                for (ptr = 0; ptr < num_sqbs; ptr++) {
-                       bufptr = otx2_alloc_rbuf(pfvf, pool);
-                       if (bufptr <= 0)
-                               return bufptr;
+                       if (otx2_alloc_rbuf(pfvf, pool, &bufptr))
+                               return -ENOMEM;
                        otx2_aura_freeptr(pfvf, pool_id, bufptr);
                        sq->sqb_ptrs[sq->sqb_count++] = (u64)bufptr;
                }
@@ -1280,7 +1279,7 @@ int otx2_rq_aura_pool_init(struct otx2_nic *pfvf)
        int stack_pages, pool_id, rq;
        struct otx2_pool *pool;
        int err, ptr, num_ptrs;
-       s64 bufptr;
+       dma_addr_t bufptr;
 
        num_ptrs = pfvf->qset.rqe_cnt;
 
@@ -1310,9 +1309,8 @@ int otx2_rq_aura_pool_init(struct otx2_nic *pfvf)
        for (pool_id = 0; pool_id < hw->rqpool_cnt; pool_id++) {
                pool = &pfvf->qset.pool[pool_id];
                for (ptr = 0; ptr < num_ptrs; ptr++) {
-                       bufptr = otx2_alloc_rbuf(pfvf, pool);
-                       if (bufptr <= 0)
-                               return bufptr;
+                       if (otx2_alloc_rbuf(pfvf, pool, &bufptr))
+                               return -ENOMEM;
                        otx2_aura_freeptr(pfvf, pool_id,
                                          bufptr + OTX2_HEAD_ROOM);
                }

diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.h b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.h
index 143ae04..0404900 100644 (file)
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.h
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.h
@@ -485,9 +485,9 @@ static inline u64 otx2_aura_allocptr(struct otx2_nic *pfvf, int aura)
 
 /* Free pointer to a pool/aura */
 static inline void otx2_aura_freeptr(struct otx2_nic *pfvf,
-                                    int aura, s64 buf)
+                                    int aura, u64 buf)
 {
-       otx2_write128((u64)buf, (u64)aura | BIT_ULL(63),
+       otx2_write128(buf, (u64)aura | BIT_ULL(63),
                      otx2_get_regaddr(pfvf, NPA_LF_AURA_OP_FREE0));
 }
 
@@ -636,7 +636,8 @@ int otx2_txschq_config(struct otx2_nic *pfvf, int lvl);
 int otx2_txsch_alloc(struct otx2_nic *pfvf);
 int otx2_txschq_stop(struct otx2_nic *pfvf);
 void otx2_sqb_flush(struct otx2_nic *pfvf);
-dma_addr_t __otx2_alloc_rbuf(struct otx2_nic *pfvf, struct otx2_pool *pool);
+int __otx2_alloc_rbuf(struct otx2_nic *pfvf, struct otx2_pool *pool,
+                     dma_addr_t *dma);
 int otx2_rxtx_enable(struct otx2_nic *pfvf, bool enable);
 void otx2_ctx_disable(struct mbox *mbox, int type, bool npa);
 int otx2_nix_config_bp(struct otx2_nic *pfvf, bool enable);

diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c
index d0e2541..cc0dac3 100644 (file)
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c
@@ -304,7 +304,7 @@ static int otx2_rx_napi_handler(struct otx2_nic *pfvf,
 {
        struct nix_cqe_rx_s *cqe;
        int processed_cqe = 0;
-       s64 bufptr;
+       dma_addr_t bufptr;
 
        while (likely(processed_cqe < budget)) {
                cqe = (struct nix_cqe_rx_s *)CQE_ADDR(cq, cq->cq_head);
@@ -333,8 +333,7 @@ static int otx2_rx_napi_handler(struct otx2_nic *pfvf,
 
        /* Refill pool with new buffers */
        while (cq->pool_ptrs) {
-               bufptr = __otx2_alloc_rbuf(pfvf, cq->rbpool);
-               if (unlikely(bufptr <= 0)) {
+               if (unlikely(__otx2_alloc_rbuf(pfvf, cq->rbpool, &bufptr))) {
                        struct refill_work *work;
                        struct delayed_work *dwork;