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[SCSI] st: make all the fragment buffers the same size 

This patch simiplifies the fragment buffer management a bit, all the
buffers in the fragment list become the same size. This is necessary
to use the block layer API (sg driver was modified in the same way)
since the block layer API takes the same size page frames instead of
scatter gatter.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Kai Makisara <Kai.Makisara@kolumbus.fi>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
This commit is contained in:
FUJITA Tomonori 2008-12-18 14:49:39 +09:00 committed by James Bottomley
parent 97ae77a1cd
commit 9c905966c4
1 changed files with 9 additions and 9 deletions
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18
drivers/scsi/st.c
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@ -3747,20 +3747,20 @@ static int enlarge_buffer(struct st_buffer * STbuffer, int new_size, int need_dm
priority = GFP_KERNEL | __GFP_NOWARN;
if (need_dma)
priority |= GFP_DMA;
for (b_size = PAGE_SIZE, order=0; order <= 6 &&
b_size < new_size - STbuffer->buffer_size;
order++, b_size *= 2)
; /* empty */
if (STbuffer->frp_segs) {
b_size = STbuffer->frp[0].length;
order = get_order(b_size);
} else {
for (b_size = PAGE_SIZE, order = 0;
order <= 6 && b_size < new_size; order++, b_size *= 2)
; /* empty */
}
for (segs = STbuffer->frp_segs, got = STbuffer->buffer_size;
segs < max_segs && got < new_size;) {
STbuffer->frp[segs].page = alloc_pages(priority, order);
if (STbuffer->frp[segs].page == NULL) {
if (new_size - got <= (max_segs - segs) * b_size / 2) {
b_size /= 2; /* Large enough for the rest of the buffers */
order--;
continue;
}
DEB(STbuffer->buffer_size = got);
normalize_buffer(STbuffer);
return 0;