[SCSI] st: fix enlarge_buffer
This patch removes a bug in enlarge_buffer() that can make a
read or write fail under special conditions.
After changing TRY_DIRECT_IO to 0 and ST_MAX_SG to 32 in
st_options.h, a program that writes a first block of 128k and
than a second bigger block (e.g. 256k) fails. The second write
returns errno EOVERFLOW, as enlarge_buffer() checks the sg list
and detects that it already is full.
As enlarge_buffer uses different page allocation orders
depending on the size of the buffer needed, the check does not
make sense.
Signed-off-by: Bodo Stroesser <bstroesser@ts.fujitsu.com>
Acked-by: Kai Mäkisara <kai.makisara@kolumbus.fi>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index ff44b3c..a1d6986 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -3719,7 +3719,7 @@
static int enlarge_buffer(struct st_buffer * STbuffer, int new_size, int need_dma)
{
- int segs, nbr, max_segs, b_size, order, got;
+ int segs, max_segs, b_size, order, got;
gfp_t priority;
if (new_size <= STbuffer->buffer_size)
@@ -3729,9 +3729,6 @@
normalize_buffer(STbuffer); /* Avoid extra segment */
max_segs = STbuffer->use_sg;
- nbr = max_segs - STbuffer->frp_segs;
- if (nbr <= 0)
- return 0;
priority = GFP_KERNEL | __GFP_NOWARN;
if (need_dma)