On Thu, Mar 13 2008, James Bottomley wrote: > \On Fri, 2008-03-07 at 18:54 +0100, Andi Kleen wrote: > > When a user is doing IO in the kernel and wants to avoid bouncing > > it is best to just ask the block layer to allocate the memory for it. > > This patch adds two simple wrappers: blk_kmalloc and blk_alloc_pages > > and respective free functions to do this. > > > > blk_alloc_pages is a little unusual in that it takes size > > instead of order arguments -- i did this because I have later > > patches to convert it over to a new allocator which does not > > require power of two for pages. > > I really don't like this ... it's wedging something in the block layer > that shouldn't be there just to avoid doing it properly in terms of > allocations on the device dma_mask. > > I also think the kfree takes a length part is asking for trouble because > it's pretty fragile. > > However, if Jens will ack it, I'll (reluctantly) add it. I agree with you, I don't like it at all (for a variety of reasons). Since callers need to remember size for free anyway (I've always hated such interfaces), they may as well do their own allocations. I don't think the block abstraction buys us anything. If anything, add a generic allocator helper that you can pass a mask to instead. -- Jens Axboe -- 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
