[media] s2255drv: dynamic memory allocation efficiency fix

Driver was allocating a kernel buffer each time it was sending a command.
It is better to allocate this buffer once at startup.

Signed-off-by: Dean Anderson <linux-dev@sensoray.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

diff --git a/drivers/media/usb/s2255/s2255drv.c b/drivers/media/usb/s2255/s2255drv.c
index 517901b25bf8414fce8f2b1b82abc1481a6d620c..4c483adafbe96218e6bc7618743119d3e15864f6 100644 (file)
--- a/drivers/media/usb/s2255/s2255drv.c
+++ b/drivers/media/usb/s2255/s2255drv.c
@@ -260,6 +260,7 @@ struct s2255_dev {
        atomic_t                num_channels;
        int                     frames;
        struct mutex            lock;   /* channels[].vdev.lock */
+       struct mutex            cmdlock; /* protects cmdbuf */
        struct usb_device       *udev;
        struct usb_interface    *interface;
        u8                      read_endpoint;
@@ -273,6 +274,8 @@ struct s2255_dev {
        /* dsp firmware version (f2255usb.bin) */
        int                     dsp_fw_ver;
        u16                     pid; /* product id */
+#define S2255_CMDBUF_SIZE 512
+       __le32                  *cmdbuf;
 };
 
 static inline struct s2255_dev *to_s2255_dev(struct v4l2_device *v4l2_dev)
@@ -1121,11 +1124,12 @@ static int s2255_set_mode(struct s2255_vc *vc,
                          struct s2255_mode *mode)
 {
        int res;
-       __le32 *buffer;
        unsigned long chn_rev;
        struct s2255_dev *dev = to_s2255_dev(vc->vdev.v4l2_dev);
        int i;
+       __le32 *buffer = dev->cmdbuf;
 
+       mutex_lock(&dev->cmdlock);
        chn_rev = G_chnmap[vc->idx];
        dprintk(dev, 3, "%s channel: %d\n", __func__, vc->idx);
        /* if JPEG, set the quality */
@@ -1139,11 +1143,6 @@ static int s2255_set_mode(struct s2255_vc *vc,
        vc->mode = *mode;
        vc->req_image_size = get_transfer_size(mode);
        dprintk(dev, 1, "%s: reqsize %ld\n", __func__, vc->req_image_size);
-       buffer = kzalloc(512, GFP_KERNEL);
-       if (buffer == NULL) {
-               dev_err(&dev->udev->dev, "out of mem\n");
-               return -ENOMEM;
-       }
        /* set the mode */
        buffer[0] = IN_DATA_TOKEN;
        buffer[1] = (__le32) cpu_to_le32(chn_rev);
@@ -1154,7 +1153,6 @@ static int s2255_set_mode(struct s2255_vc *vc,
        res = s2255_write_config(dev->udev, (unsigned char *)buffer, 512);
        if (debug)
                s2255_print_cfg(dev, mode);
-       kfree(buffer);
        /* wait at least 3 frames before continuing */
        if (mode->restart) {
                wait_event_timeout(vc->wait_setmode,
@@ -1168,22 +1166,20 @@ static int s2255_set_mode(struct s2255_vc *vc,
        /* clear the restart flag */
        vc->mode.restart = 0;
        dprintk(dev, 1, "%s chn %d, result: %d\n", __func__, vc->idx, res);
+       mutex_unlock(&dev->cmdlock);
        return res;
 }
 
 static int s2255_cmd_status(struct s2255_vc *vc, u32 *pstatus)
 {
        int res;
-       __le32 *buffer;
        u32 chn_rev;
        struct s2255_dev *dev = to_s2255_dev(vc->vdev.v4l2_dev);
+       __le32 *buffer = dev->cmdbuf;
+
+       mutex_lock(&dev->cmdlock);
        chn_rev = G_chnmap[vc->idx];
        dprintk(dev, 4, "%s chan %d\n", __func__, vc->idx);
-       buffer = kzalloc(512, GFP_KERNEL);
-       if (buffer == NULL) {
-               dev_err(&dev->udev->dev, "out of mem\n");
-               return -ENOMEM;
-       }
        /* form the get vid status command */
        buffer[0] = IN_DATA_TOKEN;
        buffer[1] = (__le32) cpu_to_le32(chn_rev);
@@ -1191,7 +1187,6 @@ static int s2255_cmd_status(struct s2255_vc *vc, u32 *pstatus)
        *pstatus = 0;
        vc->vidstatus_ready = 0;
        res = s2255_write_config(dev->udev, (unsigned char *)buffer, 512);
-       kfree(buffer);
        wait_event_timeout(vc->wait_vidstatus,
                           (vc->vidstatus_ready != 0),
                           msecs_to_jiffies(S2255_VIDSTATUS_TIMEOUT));
@@ -1201,6 +1196,7 @@ static int s2255_cmd_status(struct s2255_vc *vc, u32 *pstatus)
        }
        *pstatus = vc->vidstatus;
        dprintk(dev, 4, "%s, vid status %d\n", __func__, *pstatus);
+       mutex_unlock(&dev->cmdlock);
        return res;
 }
 
@@ -1724,6 +1720,7 @@ static void s2255_destroy(struct s2255_dev *dev)
        mutex_destroy(&dev->lock);
        usb_put_dev(dev->udev);
        v4l2_device_unregister(&dev->v4l2_dev);
+       kfree(dev->cmdbuf);
        kfree(dev);
 }
 
@@ -2350,18 +2347,14 @@ static int s2255_start_readpipe(struct s2255_dev *dev)
 /* starts acquisition process */
 static int s2255_start_acquire(struct s2255_vc *vc)
 {
-       unsigned char *buffer;
        int res;
        unsigned long chn_rev;
        int j;
        struct s2255_dev *dev = to_s2255_dev(vc->vdev.v4l2_dev);
-       chn_rev = G_chnmap[vc->idx];
-       buffer = kzalloc(512, GFP_KERNEL);
-       if (buffer == NULL) {
-               dev_err(&dev->udev->dev, "out of mem\n");
-               return -ENOMEM;
-       }
+       __le32 *buffer = dev->cmdbuf;
 
+       mutex_lock(&dev->cmdlock);
+       chn_rev = G_chnmap[vc->idx];
        vc->last_frame = -1;
        vc->bad_payload = 0;
        vc->cur_frame = 0;
@@ -2371,24 +2364,26 @@ static int s2255_start_acquire(struct s2255_vc *vc)
        }
 
        /* send the start command */
-       *(__le32 *) buffer = IN_DATA_TOKEN;
-       *((__le32 *) buffer + 1) = (__le32) cpu_to_le32(chn_rev);
-       *((__le32 *) buffer + 2) = CMD_START;
+       buffer[0] = IN_DATA_TOKEN;
+       buffer[1] = (__le32) cpu_to_le32(chn_rev);
+       buffer[2] = CMD_START;
        res = s2255_write_config(dev->udev, (unsigned char *)buffer, 512);
        if (res != 0)
                dev_err(&dev->udev->dev, "CMD_START error\n");
 
        dprintk(dev, 2, "start acquire exit[%d] %d\n", vc->idx, res);
-       kfree(buffer);
+       mutex_unlock(&dev->cmdlock);
        return 0;
 }
 
 static int s2255_stop_acquire(struct s2255_vc *vc)
 {
-       unsigned char *buffer;
        int res;
        unsigned long chn_rev;
        struct s2255_dev *dev = to_s2255_dev(vc->vdev.v4l2_dev);
+       __le32 *buffer = dev->cmdbuf;
+
+       mutex_lock(&dev->cmdlock);
        chn_rev = G_chnmap[vc->idx];
        buffer = kzalloc(512, GFP_KERNEL);
        if (buffer == NULL) {
@@ -2396,15 +2391,17 @@ static int s2255_stop_acquire(struct s2255_vc *vc)
                return -ENOMEM;
        }
        /* send the stop command */
-       *(__le32 *) buffer = IN_DATA_TOKEN;
-       *((__le32 *) buffer + 1) = (__le32) cpu_to_le32(chn_rev);
-       *((__le32 *) buffer + 2) = CMD_STOP;
+       buffer[0] = IN_DATA_TOKEN;
+       buffer[1] = (__le32) cpu_to_le32(chn_rev);
+       buffer[2] = CMD_STOP;
+
        res = s2255_write_config(dev->udev, (unsigned char *)buffer, 512);
        if (res != 0)
                dev_err(&dev->udev->dev, "CMD_STOP error\n");
-       kfree(buffer);
+
        vc->b_acquire = 0;
        dprintk(dev, 4, "%s: chn %d, res %d\n", __func__, vc->idx, res);
+       mutex_unlock(&dev->cmdlock);
        return res;
 }
 
@@ -2451,18 +2448,27 @@ static int s2255_probe(struct usb_interface *interface,
        int retval = -ENOMEM;
        __le32 *pdata;
        int fw_size;
+
        /* allocate memory for our device state and initialize it to zero */
        dev = kzalloc(sizeof(struct s2255_dev), GFP_KERNEL);
        if (dev == NULL) {
                s2255_dev_err(&interface->dev, "out of memory\n");
                return -ENOMEM;
        }
+
+       dev->cmdbuf = kzalloc(S2255_CMDBUF_SIZE, GFP_KERNEL);
+       if (dev->cmdbuf == NULL) {
+               s2255_dev_err(&interface->dev, "out of memory\n");
+               return -ENOMEM;
+       }
+
        atomic_set(&dev->num_channels, 0);
        dev->pid = le16_to_cpu(id->idProduct);
        dev->fw_data = kzalloc(sizeof(struct s2255_fw), GFP_KERNEL);
        if (!dev->fw_data)
                goto errorFWDATA1;
        mutex_init(&dev->lock);
+       mutex_init(&dev->cmdlock);
        /* grab usb_device and save it */
        dev->udev = usb_get_dev(interface_to_usbdev(interface));
        if (dev->udev == NULL) {
@@ -2568,6 +2574,7 @@ errorUDEV:
        kfree(dev->fw_data);
        mutex_destroy(&dev->lock);
 errorFWDATA1:
+       kfree(dev->cmdbuf);
        kfree(dev);
        pr_warn("Sensoray 2255 driver load failed: 0x%x\n", retval);
        return retval;