Messages in this thread | | | Date | Tue, 2 Jan 2007 11:01:36 +0000 | From | Christoph Hellwig <> | Subject | Re: [patch] remove redundant iov segment check |
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> I wonder if it wouldn't be better to make this change as part of a > larger change that moves towards an explicit iovec container struct > rather than bare 'struct iov *' and 'nr_segs' arguments. The struct > could have a flag that expressed whether the elements had been > checked. A helper could be called by the upper and lower code paths > which does the checking, marks the flag, and avoids checking again if > the flag is set. > > We've wanted an explicit struct in the past to avoid the multiple > walks of iovecs that various paths do for their own reasons. The > iovec walk that is checking for length wrapping could also be > building a bitmap of length alignment that O_DIRECT could be using to > test 512B alignment without having to walk the iovec again.
I suspect it should be rather trivial to get this started. As a first step we simply add a
struct iodesc { int nr_segs; struct iovec ioc[] };
And then we can add fields where nessecary. First a full_length one to avoid the loops to calculate thw whole I/O size, then flags for the alignment check, etc.. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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