[SCSI] fix write buffer length in scsi_req_map_sg()
sg's may have setup a the buffer with a different length than
the transfer length so we should be using the bufflen passed
in as the request's data len.
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index a417a6ff..277f1b6 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -301,7 +301,7 @@
{
struct request_queue *q = rq->q;
int nr_pages = (bufflen + sgl[0].offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
- unsigned int data_len = 0, len, bytes, off;
+ unsigned int data_len = bufflen, len, bytes, off;
struct page *page;
struct bio *bio = NULL;
int i, err, nr_vecs = 0;
@@ -310,10 +310,15 @@
page = sgl[i].page;
off = sgl[i].offset;
len = sgl[i].length;
- data_len += len;
- while (len > 0) {
+ while (len > 0 && data_len > 0) {
+ /*
+ * sg sends a scatterlist that is larger than
+ * the data_len it wants transferred for certain
+ * IO sizes
+ */
bytes = min_t(unsigned int, len, PAGE_SIZE - off);
+ bytes = min(bytes, data_len);
if (!bio) {
nr_vecs = min_t(int, BIO_MAX_PAGES, nr_pages);
@@ -345,12 +350,13 @@
page++;
len -= bytes;
+ data_len -=bytes;
off = 0;
}
}
rq->buffer = rq->data = NULL;
- rq->data_len = data_len;
+ rq->data_len = bufflen;
return 0;
free_bios:
