firewire: nosy: convert to unlocked ioctl
The required serialization of NOSY_IOC_START and NOSY_IOC_STOP is
already provided by the client_list_lock.
NOSY_IOC_FILTER does not really require serialization since accesses
to tcode_mask are atomic on any sane CPU architecture. Nevertheless,
make it explicit that we want this to be atomic by means of
client_list_lock (which also surrounds the other tcode_mask access in
the IRQ handler). While we are at it, change the type of tcode_mask to
u32 for consistency with the user API.
NOSY_IOC_GET_STATS does not require serialization against itself. But
there is a bug here regarding concurrent updates of the two counters
by the IRQ handler. Fix it by taking the client_list_lock in this ioctl
too.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
diff --git a/drivers/firewire/nosy.c b/drivers/firewire/nosy.c
index ea392d0..6470514 100644
--- a/drivers/firewire/nosy.c
+++ b/drivers/firewire/nosy.c
@@ -108,7 +108,7 @@
struct client {
struct pcilynx *lynx;
- unsigned long tcode_mask;
+ u32 tcode_mask;
struct packet_buffer buffer;
struct list_head link;
};
@@ -351,17 +351,20 @@
return packet_buffer_get(&client->buffer, buffer, count);
}
-static int
-nosy_ioctl(struct inode *inode, struct file *file,
- unsigned int cmd, unsigned long arg)
+static long
+nosy_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct client *client = file->private_data;
+ spinlock_t *client_list_lock = &client->lynx->client_list_lock;
struct nosy_stats stats;
switch (cmd) {
case NOSY_IOC_GET_STATS:
+ spin_lock_irq(client_list_lock);
stats.total_packet_count = client->buffer.total_packet_count;
- stats.lost_packet_count = client->buffer.lost_packet_count;
+ stats.lost_packet_count = client->buffer.lost_packet_count;
+ spin_unlock_irq(client_list_lock);
+
if (copy_to_user((void *) arg, &stats, sizeof stats))
return -EFAULT;
else
@@ -376,7 +379,9 @@
return 0;
case NOSY_IOC_FILTER:
+ spin_lock_irq(client_list_lock);
client->tcode_mask = arg;
+ spin_unlock_irq(client_list_lock);
return 0;
default:
@@ -386,12 +391,12 @@
}
static const struct file_operations nosy_ops = {
- .owner = THIS_MODULE,
- .read = nosy_read,
- .ioctl = nosy_ioctl,
- .poll = nosy_poll,
- .open = nosy_open,
- .release = nosy_release,
+ .owner = THIS_MODULE,
+ .read = nosy_read,
+ .unlocked_ioctl = nosy_ioctl,
+ .poll = nosy_poll,
+ .open = nosy_open,
+ .release = nosy_release,
};
#define PHY_PACKET_SIZE 12 /* 1 payload, 1 inverse, 1 ack = 3 quadlets */
@@ -409,7 +414,7 @@
{
unsigned long flags;
struct client *client;
- unsigned long tcode_mask;
+ u32 tcode_mask;
size_t length;
struct link_packet *packet;
struct timeval tv;