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ntb: no sleep in ntb_async_tx_submit
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Do not sleep in ntb_async_tx_submit, which could deadlock.
This reverts commit "8c874cc140d667f84ae4642bb5b5e0d6396d2ca4"

Fixes: 8c874cc ("NTB: Address out of DMA descriptor issue with NTB")
Reported-by: Jia-Ju Bai <baijiaju1990@163.com>
Signed-off-by: Allen Hubbe <Allen.Hubbe@dell.com>
Acked-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>
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Allen Hubbe authored and Jon Mason committed Jun 19, 2017
1 parent 5eb449e commit 88931ec
Showing 1 changed file with 7 additions and 43 deletions.
50 changes: 7 additions & 43 deletions drivers/ntb/ntb_transport.c
Original file line number Diff line number Diff line change
@@ -177,14 +177,12 @@ struct ntb_transport_qp {
u64 rx_err_ver;
u64 rx_memcpy;
u64 rx_async;
u64 dma_rx_prep_err;
u64 tx_bytes;
u64 tx_pkts;
u64 tx_ring_full;
u64 tx_err_no_buf;
u64 tx_memcpy;
u64 tx_async;
u64 dma_tx_prep_err;
};

struct ntb_transport_mw {
@@ -254,8 +252,6 @@ enum {
#define QP_TO_MW(nt, qp) ((qp) % nt->mw_count)
#define NTB_QP_DEF_NUM_ENTRIES 100
#define NTB_LINK_DOWN_TIMEOUT 10
#define DMA_RETRIES 20
#define DMA_OUT_RESOURCE_TO msecs_to_jiffies(50)

static void ntb_transport_rxc_db(unsigned long data);
static const struct ntb_ctx_ops ntb_transport_ops;
@@ -516,12 +512,6 @@ static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
out_offset += snprintf(buf + out_offset, out_count - out_offset,
"free tx - \t%u\n",
ntb_transport_tx_free_entry(qp));
out_offset += snprintf(buf + out_offset, out_count - out_offset,
"DMA tx prep err - \t%llu\n",
qp->dma_tx_prep_err);
out_offset += snprintf(buf + out_offset, out_count - out_offset,
"DMA rx prep err - \t%llu\n",
qp->dma_rx_prep_err);

out_offset += snprintf(buf + out_offset, out_count - out_offset,
"\n");
@@ -768,8 +758,6 @@ static void ntb_qp_link_down_reset(struct ntb_transport_qp *qp)
qp->tx_err_no_buf = 0;
qp->tx_memcpy = 0;
qp->tx_async = 0;
qp->dma_tx_prep_err = 0;
qp->dma_rx_prep_err = 0;
}

static void ntb_qp_link_cleanup(struct ntb_transport_qp *qp)
@@ -1317,7 +1305,6 @@ static int ntb_async_rx_submit(struct ntb_queue_entry *entry, void *offset)
struct dmaengine_unmap_data *unmap;
dma_cookie_t cookie;
void *buf = entry->buf;
int retries = 0;

len = entry->len;
device = chan->device;
@@ -1346,22 +1333,11 @@ static int ntb_async_rx_submit(struct ntb_queue_entry *entry, void *offset)

unmap->from_cnt = 1;

for (retries = 0; retries < DMA_RETRIES; retries++) {
txd = device->device_prep_dma_memcpy(chan,
unmap->addr[1],
unmap->addr[0], len,
DMA_PREP_INTERRUPT);
if (txd)
break;

set_current_state(TASK_INTERRUPTIBLE);
schedule_timeout(DMA_OUT_RESOURCE_TO);
}

if (!txd) {
qp->dma_rx_prep_err++;
txd = device->device_prep_dma_memcpy(chan, unmap->addr[1],
unmap->addr[0], len,
DMA_PREP_INTERRUPT);
if (!txd)
goto err_get_unmap;
}

txd->callback_result = ntb_rx_copy_callback;
txd->callback_param = entry;
@@ -1606,7 +1582,6 @@ static int ntb_async_tx_submit(struct ntb_transport_qp *qp,
struct dmaengine_unmap_data *unmap;
dma_addr_t dest;
dma_cookie_t cookie;
int retries = 0;

device = chan->device;
dest = qp->tx_mw_phys + qp->tx_max_frame * entry->tx_index;
@@ -1628,21 +1603,10 @@ static int ntb_async_tx_submit(struct ntb_transport_qp *qp,

unmap->to_cnt = 1;

for (retries = 0; retries < DMA_RETRIES; retries++) {
txd = device->device_prep_dma_memcpy(chan, dest,
unmap->addr[0], len,
DMA_PREP_INTERRUPT);
if (txd)
break;

set_current_state(TASK_INTERRUPTIBLE);
schedule_timeout(DMA_OUT_RESOURCE_TO);
}

if (!txd) {
qp->dma_tx_prep_err++;
txd = device->device_prep_dma_memcpy(chan, dest, unmap->addr[0], len,
DMA_PREP_INTERRUPT);
if (!txd)
goto err_get_unmap;
}

txd->callback_result = ntb_tx_copy_callback;
txd->callback_param = entry;

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