From b888429c202197916c8c549811a2dd62f090280d Mon Sep 17 00:00:00 2001 From: Sebastian Sanchez Date: Fri, 26 May 2017 05:35:44 -0700 Subject: [PATCH] IB/hfi1: Remove atomic SDMA_REQ_SEND_DONE bit operation The atomic SDMA_REQ_SEND_DONE bit is set by the process-level code, and then the same process-level code uses the bit to test that all packets have been submitted incurring a costly atomic read. Use a bool type with a READ_ONCE/WRITE_ONCE pairing for this bit, and use the same condition that is used to set the bit to test that all packets have been submitted. Reviewed-by: Mike Marciniszyn Signed-off-by: Sebastian Sanchez Signed-off-by: Dennis Dalessandro Signed-off-by: Doug Ledford --- drivers/infiniband/hw/hfi1/user_sdma.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/infiniband/hw/hfi1/user_sdma.c b/drivers/infiniband/hw/hfi1/user_sdma.c index 92517cebb4c7..6fb70f0064a6 100644 --- a/drivers/infiniband/hw/hfi1/user_sdma.c +++ b/drivers/infiniband/hw/hfi1/user_sdma.c @@ -154,10 +154,8 @@ MODULE_PARM_DESC(sdma_comp_size, "Size of User SDMA completion ring. Default: 12 #define TXREQ_FLAGS_REQ_DISABLE_SH BIT(1) /* Disable header suppression */ /* SDMA request flag bits */ -#define SDMA_REQ_FOR_THREAD 1 -#define SDMA_REQ_SEND_DONE 2 -#define SDMA_REQ_HAS_ERROR 3 -#define SDMA_REQ_DONE_ERROR 4 +#define SDMA_REQ_HAS_ERROR 1 +#define SDMA_REQ_DONE_ERROR 2 #define SDMA_PKT_Q_INACTIVE BIT(0) #define SDMA_PKT_Q_ACTIVE BIT(1) @@ -258,6 +256,7 @@ struct user_sdma_request { u16 tididx; /* progress index moving along the iovs array */ u8 iov_idx; + u8 done; struct user_sdma_iovec iovs[MAX_VECTORS_PER_REQ]; } ____cacheline_aligned_in_smp; @@ -628,6 +627,7 @@ int hfi1_user_sdma_process_request(struct hfi1_filedata *fd, req->seqsubmitted = 0; req->flags = 0; req->tids = NULL; + req->done = 0; INIT_LIST_HEAD(&req->txps); memcpy(&req->info, &info, sizeof(info)); @@ -809,7 +809,7 @@ int hfi1_user_sdma_process_request(struct hfi1_filedata *fd, * request have been submitted to the SDMA engine. However, it * will not wait for send completions. */ - while (!test_bit(SDMA_REQ_SEND_DONE, &req->flags)) { + while (req->seqsubmitted != req->info.npkts) { ret = user_sdma_send_pkts(req, pcount); if (ret < 0) { if (ret != -EBUSY) { @@ -1118,7 +1118,7 @@ static int user_sdma_send_pkts(struct user_sdma_request *req, unsigned maxpkts) ret = sdma_send_txlist(req->sde, &pq->busy, &req->txps, &count); req->seqsubmitted += count; if (req->seqsubmitted == req->info.npkts) { - set_bit(SDMA_REQ_SEND_DONE, &req->flags); + WRITE_ONCE(req->done, 1); /* * The txreq has already been submitted to the HW queue * so we can free the AHG entry now. Corruption will not @@ -1585,7 +1585,7 @@ static void user_sdma_txreq_cb(struct sdma_txreq *txreq, int status) if (status != SDMA_TXREQ_S_OK) req->status = status; if (req->seqcomp == (ACCESS_ONCE(req->seqsubmitted) - 1) && - (test_bit(SDMA_REQ_SEND_DONE, &req->flags) || + (READ_ONCE(req->done) || test_bit(SDMA_REQ_DONE_ERROR, &req->flags))) { user_sdma_free_request(req, false); pq_update(pq); -- 2.45.2