v2 version that addresses all the earlier review comments
minus patches that were already merged.
I think this one is ready for merge now. Andrew, could you please
Signed-off-by: Andi Kleen
With BKL-less sysctls most of the writable string sysctls are racy. There
is no locking on the reader side, so a reader could see an inconsistent
string or worse miss the terminating null and walk of beyond it.
This patch kit adds a new "rcu string" variant to avoid these
problems and convers the racy users. One the writer side the strings are
always copied to new memory and the readers use rcu_read_lock()
to get a stable view. For readers who access the string over
sleeps the reader copies the string.
This is all hidden in a new generic "rcu_string" ADT which can be also
used for other purposes.
This finally implements all the letters in RCU, most other users
leave out the 'C'.
I left some obscure users in architectures (sparc, mips) alone and audited
all of the others. The sparc reboot_cmd one has references to asm files
which I didn't want to touch and the mips variant seemd just too obscure.
All the others are not racy.