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authorBodo Stroesser <bstroesser@ts.fujitsu.com>2013-12-02 21:52:10 +0400
committerJames Bottomley <JBottomley@Parallels.com>2013-12-20 08:56:28 +0400
commit769989a4a09d7c825e182cf60604c06d8f2f70e4 (patch)
tree273cb753047de8d2f10cd916acbabc8bc1587af6 /drivers/scsi/st.c
parent762a86a901417280b2af9e2004f05d7481f30441 (diff)
downloadlinux-769989a4a09d7c825e182cf60604c06d8f2f70e4.tar.xz
[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>
Diffstat (limited to 'drivers/scsi/st.c')
-rw-r--r--drivers/scsi/st.c5
1 files changed, 1 insertions, 4 deletions
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index ff44b3c2cff2..a1d6986261a3 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -3719,7 +3719,7 @@ static struct st_buffer *new_tape_buffer(int need_dma, int max_sg)
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 @@ static int enlarge_buffer(struct st_buffer * STbuffer, int new_size, int need_dm
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)