Messages in this thread Patch in this message | | | Date | Sun, 16 May 2004 12:13:13 +0300 | From | Faik Uygur <> | Subject | Re: [PATCH] use idr_get_new to allocate a bus id in drivers/i2c/i2c-core.c |
| |
On Sat, 15 May 2004, Andrew Morton wrote:
> The IDR interface is a bit cumbersome. Even though you called > idr_pre_get(), there's no guarantee that the memory which it preallocated > is still present when you call idr_get_new().
Thanks for the correction.
> Is the kernel likely to ever have so many bus IDs that we actually need > this patch? Or do you specifically want first-fit-from-zero for some > reason?
Actually there is no special need for this. It is just what i think would be the expected behaviour. There was a thread two weeks ago about this issue:
http://marc.theaimsgroup.com/?l=linux-kernel&m=108370586601550&w=2
here is the updated patch:
diff -Nru a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c --- a/drivers/i2c/i2c-core.c Sun May 16 11:55:29 2004 +++ b/drivers/i2c/i2c-core.c Sun May 16 11:55:29 2004 @@ -28,6 +28,7 @@ #include <linux/slab.h> #include <linux/i2c.h> #include <linux/init.h> +#include <linux/idr.h> #include <linux/seq_file.h> #include <asm/uaccess.h> @@ -35,6 +36,7 @@ static LIST_HEAD(adapters); static LIST_HEAD(drivers); static DECLARE_MUTEX(core_lists); +static DEFINE_IDR(i2c_adapter_idr); int i2c_device_probe(struct device *dev) { @@ -113,13 +115,19 @@ */ int i2c_add_adapter(struct i2c_adapter *adap) { - static int nr = 0; + int id, res = 0; struct list_head *item; struct i2c_driver *driver; down(&core_lists); - adap->nr = nr++; + if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0) { + res = -ENOMEM; + goto out_unlock; + } + + id = idr_get_new(&i2c_adapter_idr, NULL); + adap->nr = id & MAX_ID_MASK; init_MUTEX(&adap->bus_lock); init_MUTEX(&adap->clist_lock); list_add_tail(&adap->list,&adapters); @@ -151,10 +159,12 @@ /* We ignore the return code; if it fails, too bad */ driver->attach_adapter(adap); } - up(&core_lists); dev_dbg(&adap->dev, "registered as adapter #%d\n", adap->nr); - return 0; + + out_unlock: + up(&core_lists); + return res; } @@ -207,6 +217,9 @@ /* wait for sysfs to drop all references */ wait_for_completion(&adap->dev_released); wait_for_completion(&adap->class_dev_released); + + /* free dynamically allocated bus id */ + idr_remove(&i2c_adapter_idr, adap->nr); dev_dbg(&adap->dev, "adapter unregistered\n");
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |