On 6/16/20 2:53 PM, Joe Perches wrote:
On Mon, 2020-06-15 at 21:57 -0400, Waiman Long wrote:v4: - Break out the memzero_explicit() change as suggested by Dan Carpenter so that it can be backported to stable. - Drop the "crypto: Remove unnecessary memzero_explicit()" patch for now as there can be a bit more discussion on what is best. It will be introduced as a separate patch later on after this one is merged.To this larger audience and last week without reply: https://lore.kernel.org/lkml/573b3fbd5927c643920e1364230c296b23e7584d.camel@xxxxxxxxxxx/ Are there _any_ fastpath uses of kfree or vfree?
I am not sure about that, but both of them can be slow.
is_kernel_rodata() is inlined, but is_vmalloc_addr() isn't. So the overhead can be a bit bigger.Many patches have been posted recently to fix mispairings of specific types of alloc and free functions. To eliminate these mispairings at a runtime cost of four comparisons, should the kfree/vfree/kvfree/kfree_const functions be consolidated into a single kfree? Something like the below: void kfree(const void *addr) { if (is_kernel_rodata((unsigned long)addr)) return; if (is_vmalloc_addr(addr)) _vfree(addr); else _kfree(addr); }
Cheers, Longman