allocating bounce and k_xfers at every iteration was a source of
excess delays.
---
drivers/spi/spidev.c | 35 +++++++++++++++++++++++++++++------
1 file changed, 29 insertions(+), 6 deletions(-)
diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index 2e0655d..dda7632 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -85,6 +85,8 @@ struct spidev_data {
struct mutex buf_lock;
unsigned users;
u8 *buffer;
+ struct spi_ioc_transfer *bounce;
+ struct spi_transfer *k_xfers;
};
static LIST_HEAD(device_list);
@@ -227,9 +229,9 @@ static int spidev_message(struct spidev_data *spidev,
int status = -EFAULT;
spi_message_init(&msg);
- k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL);
- if (k_xfers == NULL)
- return -ENOMEM;
+ if (n_xfers * sizeof(*k_tmp) > bufsiz)
+ return -ENOMEM;
+ k_xfers = spidev->k_xfers;
/* Construct spi_message, copying any tx data to bounce buffer.
* We walk the array of user-provided transfers, using each one
@@ -302,7 +304,6 @@ static int spidev_message(struct spidev_data *spidev,
status = total;
done:
- kfree(k_xfers);
return status;
}
@@ -451,8 +452,12 @@ spidev_ioctl(struct file *filp, unsigned int cmd, unsigned
long arg)
if (n_ioc == 0)
break;
+ if(tmp > bufsiz) {
+ retval = -EINVAL;
+ break;
+ }
/* copy into scratch area */
- ioc = kmalloc(tmp, GFP_KERNEL);
+ ioc = spidev->bounce;
if (!ioc) {
retval = -ENOMEM;
break;
@@ -465,7 +470,6 @@ spidev_ioctl(struct file *filp, unsigned int cmd, unsigned
long arg)
/* translate to spi_message, execute */
retval = spidev_message(spidev, ioc, n_ioc);
- kfree(ioc);
break;
}
@@ -504,6 +508,19 @@ static int spidev_open(struct inode *inode, struct file
*filp)
dev_dbg(&spidev->spi->dev, "open/ENOMEM\n");
status = -ENOMEM;
}
+ spidev->bounce = kmalloc(bufsiz, GFP_KERNEL);
+ if (!spidev->bounce) {
+ dev_dbg(&spidev->spi->dev, "open/ENOMEM\n");
+ kfree(spidev->buffer);
+ status = -ENOMEM;
+ }
+ spidev->k_xfers = kmalloc(bufsiz, GFP_KERNEL);
+ if (!spidev->k_xfers) {
+ dev_dbg(&spidev->spi->dev, "open/ENOMEM\n");
+ kfree(spidev->buffer);
+ kfree(spidev->bounce);
+ status = -ENOMEM;
+ }
}
if (status == 0) {
spidev->users++;
@@ -534,6 +551,12 @@ static int spidev_release(struct inode *inode, struct file
*filp)
kfree(spidev->buffer);
spidev->buffer = NULL;
+ kfree(spidev->bounce);
+ spidev->bounce = NULL;
+
+ kfree(spidev->k_xfers);
+ spidev->k_xfers = NULL;
+
/* ... after we unbound from the underlying device? */
spin_lock_irq(&spidev->spi_lock);
dofree = (spidev->spi == NULL);
--
2.1.0
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