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authorMike Christie <michaelc@cs.wisc.edu>2007-03-13 12:52:29 -0500
committerJames Bottomley <jejb@mulgrave.localdomain>2007-10-12 14:38:17 -0400
commitbd441deaf341c524b28fd72831ebf6fef88f1c41 (patch)
treef75f1170a90b55992a340c64e2ed52ecbfb19bce
parent358147403d1506ee43335c152fa3864d90f5ef6e (diff)
[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>
-rw-r--r--drivers/scsi/scsi_lib.c14
1 files changed, 10 insertions, 4 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index a417a6ff9f9..277f1b64e9a 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -301,7 +301,7 @@ static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl,
{
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 @@ static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl,
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 @@ static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl,
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: