On Wed, Mar 28, 2018 at 03:43:40PM +0300, Leon Romanovsky wrote: > From: Parav Pandit <parav@xxxxxxxxxxxx> > > Currently following inconsistencies exist. > 1. ib_query_gid() returns GID from the software cache for a RoCE port > and returns GID from the HCA for an IB port. > This is incorrect because software GID cache is maintained regardless > of HCA port type. > > 2. GID is queries from the HCA via ib_query_gid and updated in the > software cache for IB link layer. Both of them might not be in sync. > > ULPs such as SRP initiator, SRP target, IPoIB driver have historically > used ib_query_gid() API to query the GID. However CM used cached version > during CM processing, When software cache was introduced, this > inconsitency remained. > > In order to simplify, improve readability and avoid link layer > specific above inconsistencies, this patch brings following changes. > > 1. ib_query_gid() always refers to the cache layer regardless of link > layer. > > 2. cache module who reads the GID entry from HCA and builds the cache, > directly invokes the HCA provider verb's query_gid() callback function. > > 3. ib_query_port() is being called in early stage where GID cache is not > yet build while reading port immutable property. Therefore it needs to > read the default GID from the HCA for IB link layer to publish the > subnet prefix. > > Signed-off-by: Parav Pandit <parav@xxxxxxxxxxxx> > Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx> > --- > drivers/infiniband/core/cache.c | 4 ++-- > drivers/infiniband/core/device.c | 12 +++--------- > 2 files changed, 5 insertions(+), 11 deletions(-) This is quite a big thing to change.. I'd really like to see it done though, the confusing API just does not seem necessary. I know the 'cache' was originally created because we needed to access the GID entries without sleeping. But why wasn't everything converted to use the cache? The only reason I can think of is that there are situations where the cache does not have new-enough data? Ie a MAD updated the HCA and now have some race between cache and HCA? Is that possible? I'm nervous. Do you think it would make sense to add some kind of 'force refresh' flag to this API and set it for all the places that currently don't use the cache API? 'force refresh' would guarentee that the latest data from the IB HCA is returned as we have today, but otherwise still present the common cache API, and be a NOP flag for roce? Sean: What do you think? Can you remember that far back any better? Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
