Mutex and Spinlock locked together

Check this out:

drivers/infiniband/core/cache.c

function: ib_cache_gid_add

Line: 338

mutex_lock(&table->lock);
        write_lock_irq(&table->rwlock);
.
.
.
.
 write_unlock_irq(&table->rwlock);
        mutex_unlock(&table->lock);

On Thu, Feb 25, 2016 at 3:42 PM, priyaranjan [off-list ref]
wrote:

quoted

On Thu, Feb 25, 2016 at 2:53 PM, Devesh Sharma [off-list ref]

wrote:

quoted

Hi

quoted

In running kernel there are many places you can look to get the usage.

But the bottom line is

Can you tell me the specific use case?  or give me the file name/driver
where this is used.

quoted

* You can take a spinlock under a mutex. e.g.

mutex_lock--->spinlock-----critical section-----spinunlock--->mutex_unlock.

quoted

* You can not take a mutex under a spinlock. e.g. spinlock--->mutex_lock

-----critical section ....mutex_unlock---->spinunlock is not allowed.


On Thu, Feb 25, 2016 at 11:37 AM, priyaranjan [off-list ref]
wrote:
Hello All,

Do you have any idea of a situation where we would need mutex and spinlock
to be locked together? I think there is an example for this in Linux
kernel. Can anyone help me?

Regards,
Priyaranjan

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