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Commit b888429c authored by Sebastian Sanchez's avatar Sebastian Sanchez Committed by Doug Ledford
Browse files

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: default avatarMike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: default avatarSebastian Sanchez <sebastian.sanchez@intel.com>
Signed-off-by: default avatarDennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: default avatarDoug Ledford <dledford@redhat.com>
parent cb49366f

drivers/infiniband/hw/hfi1/user_sdma.c

+7 −7
Original line number Diff line number Diff line
@@ -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);