From: Bodo Stroesser Date: Mon, 2 Dec 2013 17:52:10 +0000 (+0100) Subject: [SCSI] st: fix enlarge_buffer X-Git-Tag: next-20131220~13^2~2 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=322d8f1e91eb653b41796d05f541013ef2b60be2;p=karo-tx-linux.git [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 Acked-by: Kai Mäkisara Signed-off-by: James Bottomley --- 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)