29/03/2018 07:38, Shahaf Shuler: > Wednesday, March 21, 2018 9:48 PM, Ferruh Yigit: > > DEV_RX_OFFLOAD_KEEP_CRC offload flag added. > > > > DEV_RX_OFFLOAD_CRC_STRIP flag will remain one more release but default > > behavior in PMDs is to strip the CRC independent from this flag. > > > > Until DEV_RX_OFFLOAD_CRC_STRIP flag is removed: > > - Setting both KEEP_CRC & CRC_STRIP is INVALID > > - Setting only CRC_STRIP PMD should strip the CRC > > - Setting only KEEP_CRC PMD should keep the CRC > > - Not setting both PMD should strip the CRC > > We cannot have such default behavior, it may break existing applications. > > The API of ethdev offloads says (even though it is not well documented) : > DEV_RX_OFFLOAD_CRC_STRIP (emphasis the STRIP). > meaning, if set -> STRIP, if not set -> don't strip. I am aware to at least > one application which wants to have the CRC, and for that purpose it > naturally don't set the offload flag. > > The fact some PMDs lack the ability to toggle the CRC stripping should be > exposed in the "limitations" section of their related guide. > > Up to here, this is the behavior as defined by the API. > > Now, we want to change it, and I think it makes sense. However I think we > should take similar approach to what we did with the ethdev offloads API: > 1. at first stage a new offload flag is exposed DEV_RX_OFFLOAD_KEEP_CRC and > implemented on the PMDs.
This is what is proposed above, except that we change the default behaviour. If we introduce a new flag which is the contrary of the old one, we need to choose which one is the default, so which one has no effect. > 2. there is a conversion function on ethdev. Which for example converts > ~DEV_RX_OFFLOAD_CRC_STRIP -> DEV_RX_OFFLOAD_KEEP_CRC for the PMDs. > 3. deprecation of DEV_RX_OFFLOAD_CRC_STRIP for applications and remove of the > conversion functions.
