Messages in this thread | ![/](/images/icornerl.gif) | | Date | Sun, 9 Nov 2003 15:44:40 -0500 (EST) | From | Alan Stern <> | Subject | How to allocate pages for a scatter-gather buffer? |
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Jens:
Thanks for your help in tracking down that problem with the usb-storage sddr09 driver.
Now a slightly different question. Suppose I want to allocate some pages as a scatter-gather buffer for I/O to a device. I've got the device's dma_mask; what's the right way to convert that to a GFP bitmask for alloc_pages() or get_free_pages()?
Also, assuming I'll have to use memcpy() to transfer data into or out of the scatter-gather buffer (so it will have to get a kernel virtual mapping at some point), am I better off using alloc_pages() followed by kmap_atomic()/kunmap_atomic() or get_free_pages()? Or even kmalloc()?
Alan Stern
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