Commit f8195f3b authored by Don Hiatt's avatar Don Hiatt Committed by Doug Ledford
Browse files

IB/hfi1: Eliminate allocation while atomic 



The PIO trailing buffer was being dynamically allocated
but the kcalloc return value was not being checked. Further,
the GFP_KERNEL was being used even though the send engine
might be called with interrupts disabled.

Since the maximum size of the trailing buffer is only 12
bytes (CRC = 4, LT = 1, Pad = 0 to 7 bytes) just statically
allocate the buffer, remove the alloc entirely and share it
with the SDMA engine by making it global.

Reported-by: default avatarLeon Romanovsky <leon@kernel.org>
Fixes: 566d53a8 ("IB/hfi1: Enhance PIO/SDMA send for 16B")
Reviewed-by: default avatarMike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: default avatarDon Hiatt <don.hiatt@intel.com>
Signed-off-by: default avatarDennis Dalessandro <dennis.dalessandro@intel.com>
Reviewed-by: default avatarLeon Romanovsky <leon@kernel.org>
Signed-off-by: default avatarDoug Ledford <dledford@redhat.com>
parent d0a2f454

drivers/infiniband/hw/hfi1/common.h

+1 −0
Original line number Diff line number Diff line
@@ -328,6 +328,7 @@ struct diag_pkt { 
#define SC15_PACKET 0xF

#define SIZE_OF_CRC 1

#define SIZE_OF_LT 1

#define MAX_16B_PADDING 12 /* CRC = 4, LT = 1, Pad = 0 to 7 bytes */



#define LIM_MGMT_P_KEY       0x7FFF

#define FULL_MGMT_P_KEY      0xFFFF

drivers/infiniband/hw/hfi1/verbs.c

+8 −14
Original line number Diff line number Diff line
@@ -146,6 +146,9 @@ static int pio_wait(struct rvt_qp *qp, 
/* Length of buffer to create verbs txreq cache name */

#define TXREQ_NAME_LEN 24



/* 16B trailing buffer */

static const u8 trail_buf[MAX_16B_PADDING];



static uint wss_threshold;

module_param(wss_threshold, uint, S_IRUGO);

MODULE_PARM_DESC(wss_threshold, "Percentage (1-100) of LLC to use as a threshold for a cacheless copy");
@@ -814,7 +817,6 @@ static int build_verbs_tx_desc( 
	u16 hdrbytes = tx->hdr_dwords << 2;

	u32 *hdr;

	u8 extra_bytes = 0;

	static char trail_buf[12]; /* CRC = 4, LT = 1, Pad = 0 to 7 bytes */



	if (tx->phdr.hdr.hdr_type) {

		/*
@@ -869,9 +871,9 @@ static int build_verbs_tx_desc( 
	}



	/* add icrc, lt byte, and padding to flit */

	if (extra_bytes != 0)

	if (extra_bytes)

		ret = sdma_txadd_kvaddr(sde->dd, &tx->txreq,

					trail_buf, extra_bytes);

					(void *)trail_buf, extra_bytes);



bail_txadd:

	return ret;
@@ -1128,18 +1130,10 @@ int hfi1_verbs_send_pio(struct rvt_qp *qp, struct hfi1_pkt_state *ps, 
				len -= slen;

			}

		}

		/*

		 * Bypass packet will need to copy additional

		 * bytes to accommodate for CRC and LT bytes

		 */

		if (extra_bytes) {

			u8 *empty_buf;

		/* add icrc, lt byte, and padding to flit */

		if (extra_bytes)

			seg_pio_copy_mid(pbuf, trail_buf, extra_bytes);



			empty_buf = kcalloc(extra_bytes, sizeof(u8),

					    GFP_KERNEL);

			seg_pio_copy_mid(pbuf, empty_buf, extra_bytes);

			kfree(empty_buf);

		}

		seg_pio_copy_end(pbuf);

	}

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