On Tue, Mar 06, 2012 at 12:42:46PM -0500, Martin K. Petersen wrote: > >>>>> "Vivek" == Vivek Goyal <vgoyal@xxxxxxxxxx> writes: > > Vivek> So in this patch bio_is_rw() == bio_is_data(). Do they diverge in > Vivek> later patches? > > Yep. > > > Vivek> Some of the flags in REQ_NOMERGE_FLAGS are rq only and should not > Vivek> be used on bio. For example REQ_NOMERGE and REQ_STARTED. > > Right, but even if the caller passed down invalid flags they'd be masked > off when we create the request. > > > Vivek> Will it be better to define BIO_NOMERGE_FLAGS separately? > > I'd rather not have things defined two places. That leads us down the > path to the mess we have now. > > However, I don't have a problem with doing: > > #define BIO_NOMERGE_FLAGS (REQ_NOMERGE_FLAGS & REQ_COMMON_MASK) May be we can leave it as it is. Using REQ_COMMON_MASK makes things more confusing and if we want to use a bio only flag to determine whether bio should be merged or not, then it will be broken again. For example, hypothetically, if I said that any bio which has already been throttled (__REQ_THROTTLED), don't merge it, then above will not work. So may be it is better to leave it as it is and have the understanding that REQ_NOMERGE_FLAGS represents flags both for bio and reqeust. Given the fact that bio only bits will not be set in req and vice a versa, it is fine to use this either on bio or rq. May be 1-2 line of comment above REQ_NOMERGE_FLAG will help. Thanks Vivek -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
