PATCH: linux-2.5.24/Documentation/DMA-mapping.txt update for struct scatterlist change

From: Adam J. Richter (
Date: Tue Jun 25 2002 - 14:24:17 EST

Hi Linus,

        linux-2.5.24/Documentation/DMA-mapping.txt contains a few
sentences about struct scatterlist that are no longer accurate, now
that scatterlist.address has been deleetd in Linux-2.5. Dave Miller
says that I should "feel free to submit a patch" to fix this. So,
here it is.

Adam J. Richter __ ______________ 575 Oroville Road \ / Milpitas, California 95035
+1 408 309-6081 | g g d r a s i l United States of America
                         "Free Software For The Rest Of Us."

--- linux-2.5.24/Documentation/DMA-mapping.txt 2002-06-20 15:53:53.000000000 -0700
+++ linux/Documentation/DMA-mapping.txt 2002-06-25 12:16:49.000000000 -0700
@@ -759,22 +759,20 @@
    Struct scatterlist must contain, at a minimum, the following
         struct page *page;
         unsigned int offset;
         unsigned int length;
- This means that your pci_{map,unmap}_sg() and all other
- interfaces dealing with scatterlists must be able to cope
- properly with page being non NULL.
- A scatterlist is in one of two states. The base address is
- either specified by "address" or by a "page+offset" pair.
- If "address" is NULL, then "page+offset" is being used.
- If "page" is NULL, then "address" is being used.
+ The base address is specified by a "page+offset" pair.
+ Previous versions of struct scatterlist contained a "void *address"
+ field that was sometimes used instead of page+offset. As of Linux
+ 2.5., page+offset is always used, and the "address" field has been
+ deleted.
 2) More to come...
 This document, and the API itself, would not be in it's current
 form without the feedback and suggestions from numerous individuals.
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