f3d9832e56
ipv6_add_addr is called in process context with rtnl lock held (e.g., manual config of an address) or during softirq processing (e.g., autoconf and address from a router advertisement). Currently, ipv6_add_addr calls rcu_read_lock_bh shortly after entry and does not call unlock until exit, minus the call around the address validator notifier. Similarly, addrconf_hash_lock is taken after the validator notifier and held until exit. This forces the allocation of inet6_ifaddr to always be atomic. Refactor ipv6_add_addr as follows: 1. add an input boolean to discriminate the call path (process context or softirq). This new flag controls whether the alloc can be done with GFP_KERNEL or GFP_ATOMIC. 2. Move the rcu_read_lock_bh and unlock calls only around functions that do rcu updates. 3. Remove the in6_dev_hold and put added by3ad7d2468f("Ipvlan should return an error when an address is already in use."). This was done presumably because rcu_read_unlock_bh needs to be called before calling the validator. Since rcu_read_lock is not needed before the validator runs revert the hold and put added by3ad7d2468fand only do the hold when setting ifp->idev. 4. move duplicate address check and insertion of new address in the global address hash into a helper. The helper is called after an ifa is allocated and filled in. This allows the ifa for manually configured addresses to be done with GFP_KERNEL and reduces the overall amount of time with rcu_read_lock held and hash table spinlock held. Signed-off-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.