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kernel/kfifo.c: add handling of chained scatterlists

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The current kfifo scatterlist implementation will not work with chained
scatterlists.  It assumes that struct scatterlist arrays are allocated
contiguously, which is not the case when chained scatterlists (struct
sg_table) are in use.

Signed-off-by: Stefani Seibold <stefani@seibold.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Stefani Seibold 2010-08-11 14:17:27 -07:00 committed by Linus Torvalds
parent 5af568cbd5
commit d78a3eda69
1 changed files with 6 additions and 7 deletions
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13
kernel/kfifo.c
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@ -10,7 +10,7 @@
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
@ -333,17 +333,16 @@ static int setup_sgl_buf(struct scatterlist *sgl, void *buf,
buf += PAGE_SIZE;
npage = virt_to_page(buf);
if (page_to_phys(page) != page_to_phys(npage) - l) {
sgl->page_link = 0;
sg_set_page(sgl++, page, l - off, off);
if (++n == nents)
sg_set_page(sgl, page, l - off, off);
sgl = sg_next(sgl);
if (++n == nents || sgl == NULL)
return n;
page = npage;
len -= l - off;
l = off = 0;
}
}
sgl->page_link = 0;
sg_set_page(sgl++, page, len, off);
sg_set_page(sgl, page, len, off);
return n + 1;
}
@ -363,7 +362,7 @@ static unsigned int setup_sgl(struct __kfifo *fifo, struct scatterlist *sgl,
}
l = min(len, size - off);
n = setup_sgl_buf(sgl, fifo->data + off, nents, l);
n = setup_sgl_buf(sgl, fifo->data + off, nents, l);
n += setup_sgl_buf(sgl + n, fifo->data, nents - n, len - l);
if (n)