Allocate an rpc buffer
void * rpc_malloc(struct rpc_task * task, size_t size);
task
RPC task that will use this buffer
size
requested byte size
To prevent rpciod from hanging, this allocator never sleeps, returning NULL and suppressing warning if the request cannot be serviced immediately. The caller can arrange to sleep in a way that is safe for rpciod.
Most requests are 'small' (under 2KiB) and can be serviced from a mempool, ensuring that NFS reads and writes can always proceed, and that there is good locality of reference for these buffers.
In order to avoid memory starvation triggering more writebacks of NFS requests, we avoid using GFP_KERNEL.