Re: [PATCH v3 4/5] iommufd: Add replace support in iommufd_access_set_ioas()

On Thu, Mar 02, 2023 at 08:23:54AM +0000, Tian, Kevin wrote:

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From: Nicolin Chen nicolinc@nvidia.com Sent: Saturday, February 25, 2023 9:52 AM

• /*
  

•  * Set ioas to NULL to block any further iommufd_access_pin_pages().
  

•  * iommufd_access_unpin_pages() can continue using access-
  

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ioas_unpin.

•  */
  

• access->ioas = NULL;
  

• mutex_unlock(&access->ioas_lock);
  

• access->ops->unmap(access->data, 0, ULONG_MAX);
  

• mutex_lock(&access->ioas_lock);
  

This should check whether @unmap is valid.

Will change to + if (access->ops->unmap) { + mutex_unlock(&access->ioas_lock); + access->ops->unmap(access->data, 0, ULONG_MAX); + mutex_lock(&access->ioas_lock); + }

Thanks! Nic