Crrently scsi_execute_async takes a void *buffer argument that can
be either interpreted as a kernel buffer or scatterlist pointer
depending on what the use_sg argument is set to. There is no user
of the use_sg == 0 kernel buffer case and we should remove it in
favour of type safety.
And yes, long-term we should get rid of the current scsi_execute_async
interface entirely, struct scatterlist * doesn't make sense as a data
structure above the block layer.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Index: scsi-misc-2.6/drivers/scsi/scsi_lib.c
===================================================================
--- scsi-misc-2.6.orig/drivers/scsi/scsi_lib.c 2006-11-02 15:31:51.000000000 +0100
+++ scsi-misc-2.6/drivers/scsi/scsi_lib.c 2006-11-02 17:05:34.000000000 +0100
@@ -368,21 +368,24 @@
}
/**
- * scsi_execute_async - insert request
- * @sdev: scsi device
- * @cmd: scsi command
- * @cmd_len: length of scsi cdb
- * @data_direction: data direction
- * @buffer: data buffer (this can be a kernel buffer or scatterlist)
- * @bufflen: len of buffer
- * @use_sg: if buffer is a scatterlist this is the number of elements
- * @timeout: request timeout in seconds
- * @retries: number of times to retry request
- * @flags: or into request flags
+ * scsi_execute_async - execute SCSI command asynchronously
+ * @sdev: scsi device
+ * @cmd: scsi command block
+ * @cmd_len: length of scsi command block
+ * @data_direction: data direction
+ * @sg: data buffer in form of a scatterlist
+ * @data_length: total data length
+ * @use_sg: number of elements in the scatterlist
+ * @timeout: request timeout in seconds
+ * @retries: number of times to retry request
+ * @privdata: private data passed back to the done callback
+ * @done: I/O completion callback
+ * @gfp: memory allocation flags
**/
int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd,
- int cmd_len, int data_direction, void *buffer, unsigned bufflen,
- int use_sg, int timeout, int retries, void *privdata,
+ int cmd_len, int data_direction, struct scatterlist *sg,
+ unsigned data_length, int use_sg, int timeout,
+ int retries, void *privdata,
void (*done)(void *, char *, int, int), gfp_t gfp)
{
struct request *req;
@@ -390,6 +393,8 @@
int err = 0;
int write = (data_direction == DMA_TO_DEVICE);
+ BUG_ON(data_length && !use_sg);
+
sioc = kmem_cache_alloc(scsi_io_context_cache, gfp);
if (!sioc)
return DRIVER_ERROR << 24;
@@ -401,13 +406,11 @@
req->cmd_type = REQ_TYPE_BLOCK_PC;
req->cmd_flags |= REQ_QUIET;
- if (use_sg)
- err = scsi_req_map_sg(req, buffer, use_sg, bufflen, gfp);
- else if (bufflen)
- err = blk_rq_map_kern(req->q, req, buffer, bufflen, gfp);
-
- if (err)
- goto free_req;
+ if (use_sg) {
+ err = scsi_req_map_sg(req, sg, use_sg, data_length, gfp);
+ if (err)
+ goto free_req;
+ }
req->cmd_len = cmd_len;
memcpy(req->cmd, cmd, req->cmd_len);
Index: scsi-misc-2.6/include/scsi/scsi_device.h
===================================================================
--- scsi-misc-2.6.orig/include/scsi/scsi_device.h 2006-10-30 17:00:35.000000000 +0100
+++ scsi-misc-2.6/include/scsi/scsi_device.h 2006-11-02 17:05:49.000000000 +0100
@@ -293,7 +293,7 @@
struct scsi_sense_hdr *, int timeout, int retries);
extern int scsi_execute_async(struct scsi_device *sdev,
const unsigned char *cmd, int cmd_len, int data_direction,
- void *buffer, unsigned bufflen, int use_sg,
+ struct scatterlist *sg, unsigned data_length, int use_sg,
int timeout, int retries, void *privdata,
void (*done)(void *, char *, int, int),
gfp_t gfp);
-
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