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Move it outside the lock to minimize the time the mutex is held, reducing contention for concurrent accesses. Signed-off-by: Josh Law --- drivers/staging/axis-fifo/axis-fifo.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/drivers/staging/axis-fifo/axis-fifo.c b/drivers/staging/axis-fifo/axis-fifo.c index aad2206b481a..d5533235cefc 100644 --- a/drivers/staging/axis-fifo/axis-fifo.c +++ b/drivers/staging/axis-fifo/axis-fifo.c @@ -233,9 +233,15 @@ static ssize_t axis_fifo_write(struct file *f, const char __user *buf, (words_to_write > (fifo->tx_fifo_depth - 4))) return -EINVAL; + txbuf = vmemdup_user(buf, len); + if (IS_ERR(txbuf)) + return PTR_ERR(txbuf); + if (f->f_flags & O_NONBLOCK) { - if (!mutex_trylock(&fifo->write_lock)) - return -EAGAIN; + if (!mutex_trylock(&fifo->write_lock)) { + ret = -EAGAIN; + goto err_free; + } if (words_to_write > ioread32(fifo->base_addr + XLLF_TDFV_OFFSET)) { @@ -252,21 +258,17 @@ static ssize_t axis_fifo_write(struct file *f, const char __user *buf, goto end_unlock; } - txbuf = vmemdup_user(buf, len); - if (IS_ERR(txbuf)) { - ret = PTR_ERR(txbuf); - goto end_unlock; - } - for (int i = 0; i < words_to_write; ++i) iowrite32(txbuf[i], fifo->base_addr + XLLF_TDFD_OFFSET); iowrite32(len, fifo->base_addr + XLLF_TLR_OFFSET); ret = len; - kvfree(txbuf); + end_unlock: mutex_unlock(&fifo->write_lock); +err_free: + kvfree(txbuf); return ret; } -- 2.43.0