From 7801edb0b8b66e83c13623b483bc2e846c007c9d Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Mon, 21 Dec 2009 14:37:33 -0800 Subject: [PATCH] media video cx23888 driver: ported to new kfifo API Fix the cx23888 driver to use the new kfifo API. Using kfifo_reset() may result in a possible race conditions. This patch fixes it by using a spinlock around the kfifo_reset() function. Signed-off-by: Stefani Seibold Cc: Mauro Carvalho Chehab Reviewed-by: Andy Walls Acked-by: Andy Walls Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/media/video/cx23885/cx23888-ir.c | 44 ++++++++++-------------- 1 file changed, 19 insertions(+), 25 deletions(-) diff --git a/drivers/media/video/cx23885/cx23888-ir.c b/drivers/media/video/cx23885/cx23888-ir.c index 3ccc8afeccf3..2bf57a4527d3 100644 --- a/drivers/media/video/cx23885/cx23888-ir.c +++ b/drivers/media/video/cx23885/cx23888-ir.c @@ -124,15 +124,12 @@ struct cx23888_ir_state { atomic_t rxclk_divider; atomic_t rx_invert; - struct kfifo *rx_kfifo; + struct kfifo rx_kfifo; spinlock_t rx_kfifo_lock; struct v4l2_subdev_ir_parameters tx_params; struct mutex tx_params_lock; atomic_t txclk_divider; - - struct kfifo *tx_kfifo; - spinlock_t tx_kfifo_lock; }; static inline struct cx23888_ir_state *to_state(struct v4l2_subdev *sd) @@ -522,6 +519,7 @@ static int cx23888_ir_irq_handler(struct v4l2_subdev *sd, u32 status, { struct cx23888_ir_state *state = to_state(sd); struct cx23885_dev *dev = state->dev; + unsigned long flags; u32 cntrl = cx23888_ir_read4(dev, CX23888_IR_CNTRL_REG); u32 irqen = cx23888_ir_read4(dev, CX23888_IR_IRQEN_REG); @@ -594,8 +592,9 @@ static int cx23888_ir_irq_handler(struct v4l2_subdev *sd, u32 status, if (i == 0) break; j = i * sizeof(u32); - k = kfifo_put(state->rx_kfifo, - (unsigned char *) rx_data, j); + k = kfifo_in_locked(&state->rx_kfifo, + (unsigned char *) rx_data, j, + &state->rx_kfifo_lock); if (k != j) kror++; /* rx_kfifo over run */ } @@ -631,8 +630,11 @@ static int cx23888_ir_irq_handler(struct v4l2_subdev *sd, u32 status, cx23888_ir_write4(dev, CX23888_IR_CNTRL_REG, cntrl); *handled = true; } - if (kfifo_len(state->rx_kfifo) >= CX23888_IR_RX_KFIFO_SIZE / 2) + + spin_lock_irqsave(&state->rx_kfifo_lock, flags); + if (kfifo_len(&state->rx_kfifo) >= CX23888_IR_RX_KFIFO_SIZE / 2) events |= V4L2_SUBDEV_IR_RX_FIFO_SERVICE_REQ; + spin_unlock_irqrestore(&state->rx_kfifo_lock, flags); if (events) v4l2_subdev_notify(sd, V4L2_SUBDEV_IR_RX_NOTIFY, &events); @@ -657,7 +659,7 @@ static int cx23888_ir_rx_read(struct v4l2_subdev *sd, u8 *buf, size_t count, return 0; } - n = kfifo_get(state->rx_kfifo, buf, n); + n = kfifo_out_locked(&state->rx_kfifo, buf, n, &state->rx_kfifo_lock); n /= sizeof(u32); *num = n * sizeof(u32); @@ -785,7 +787,12 @@ static int cx23888_ir_rx_s_parameters(struct v4l2_subdev *sd, o->interrupt_enable = p->interrupt_enable; o->enable = p->enable; if (p->enable) { - kfifo_reset(state->rx_kfifo); + unsigned long flags; + + spin_lock_irqsave(&state->rx_kfifo_lock, flags); + kfifo_reset(&state->rx_kfifo); + /* reset tx_fifo too if there is one... */ + spin_unlock_irqrestore(&state->rx_kfifo_lock, flags); if (p->interrupt_enable) irqenable_rx(dev, IRQEN_RSE | IRQEN_RTE | IRQEN_ROE); control_rx_enable(dev, p->enable); @@ -892,7 +899,6 @@ static int cx23888_ir_tx_s_parameters(struct v4l2_subdev *sd, o->interrupt_enable = p->interrupt_enable; o->enable = p->enable; if (p->enable) { - kfifo_reset(state->tx_kfifo); if (p->interrupt_enable) irqenable_tx(dev, IRQEN_TSE); control_tx_enable(dev, p->enable); @@ -1168,18 +1174,8 @@ int cx23888_ir_probe(struct cx23885_dev *dev) return -ENOMEM; spin_lock_init(&state->rx_kfifo_lock); - state->rx_kfifo = kfifo_alloc(CX23888_IR_RX_KFIFO_SIZE, GFP_KERNEL, - &state->rx_kfifo_lock); - if (state->rx_kfifo == NULL) - return -ENOMEM; - - spin_lock_init(&state->tx_kfifo_lock); - state->tx_kfifo = kfifo_alloc(CX23888_IR_TX_KFIFO_SIZE, GFP_KERNEL, - &state->tx_kfifo_lock); - if (state->tx_kfifo == NULL) { - kfifo_free(state->rx_kfifo); + if (kfifo_alloc(&state->rx_kfifo, CX23888_IR_RX_KFIFO_SIZE, GFP_KERNEL)) return -ENOMEM; - } state->dev = dev; state->id = V4L2_IDENT_CX23888_IR; @@ -1211,8 +1207,7 @@ int cx23888_ir_probe(struct cx23885_dev *dev) sizeof(struct v4l2_subdev_ir_parameters)); v4l2_subdev_call(sd, ir, tx_s_parameters, &default_params); } else { - kfifo_free(state->rx_kfifo); - kfifo_free(state->tx_kfifo); + kfifo_free(&state->rx_kfifo); } return ret; } @@ -1231,8 +1226,7 @@ int cx23888_ir_remove(struct cx23885_dev *dev) state = to_state(sd); v4l2_device_unregister_subdev(sd); - kfifo_free(state->rx_kfifo); - kfifo_free(state->tx_kfifo); + kfifo_free(&state->rx_kfifo); kfree(state); /* Nothing more to free() as state held the actual v4l2_subdev object */ return 0; -- 2.30.2