[SCSI] Convert SCSI mid-layer to scsi_execute_async
Add scsi helpers to create really-large-requests and convert
scsi-ml to scsi_execute_async().
Per Jens's previous comments, I placed this function in scsi_lib.c.
I made it follow all the queue's limits - I think I did at least :), so
I removed the warning on the function header.
I think the scsi_execute_* functions should eventually take a request_queue
and be placed some place where the dm-multipath hw_handler can use them
if that failover code is going to stay in the kernel. That conversion
patch will be sent in another mail though.
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 18c5d25..53ea62d 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -1315,23 +1315,6 @@
}
/**
- * scsi_eh_lock_done - done function for eh door lock request
- * @scmd: SCSI command block for the door lock request
- *
- * Notes:
- * We completed the asynchronous door lock request, and it has either
- * locked the door or failed. We must free the command structures
- * associated with this request.
- **/
-static void scsi_eh_lock_done(struct scsi_cmnd *scmd)
-{
- struct scsi_request *sreq = scmd->sc_request;
-
- scsi_release_request(sreq);
-}
-
-
-/**
* scsi_eh_lock_door - Prevent medium removal for the specified device
* @sdev: SCSI device to prevent medium removal
*
@@ -1353,29 +1336,17 @@
**/
static void scsi_eh_lock_door(struct scsi_device *sdev)
{
- struct scsi_request *sreq = scsi_allocate_request(sdev, GFP_KERNEL);
+ unsigned char cmnd[MAX_COMMAND_SIZE];
- if (unlikely(!sreq)) {
- printk(KERN_ERR "%s: request allocate failed,"
- "prevent media removal cmd not sent\n", __FUNCTION__);
- return;
- }
+ cmnd[0] = ALLOW_MEDIUM_REMOVAL;
+ cmnd[1] = 0;
+ cmnd[2] = 0;
+ cmnd[3] = 0;
+ cmnd[4] = SCSI_REMOVAL_PREVENT;
+ cmnd[5] = 0;
- sreq->sr_cmnd[0] = ALLOW_MEDIUM_REMOVAL;
- sreq->sr_cmnd[1] = 0;
- sreq->sr_cmnd[2] = 0;
- sreq->sr_cmnd[3] = 0;
- sreq->sr_cmnd[4] = SCSI_REMOVAL_PREVENT;
- sreq->sr_cmnd[5] = 0;
- sreq->sr_data_direction = DMA_NONE;
- sreq->sr_bufflen = 0;
- sreq->sr_buffer = NULL;
- sreq->sr_allowed = 5;
- sreq->sr_done = scsi_eh_lock_done;
- sreq->sr_timeout_per_command = 10 * HZ;
- sreq->sr_cmd_len = COMMAND_SIZE(sreq->sr_cmnd[0]);
-
- scsi_insert_special_req(sreq, 1);
+ scsi_execute_async(sdev, cmnd, DMA_NONE, NULL, 0, 0, 10 * HZ,
+ 5, NULL, NULL, GFP_KERNEL);
}
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 1f27827..eb0cfbf 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -63,39 +63,6 @@
};
#undef SP
-
-/*
- * Function: scsi_insert_special_req()
- *
- * Purpose: Insert pre-formed request into request queue.
- *
- * Arguments: sreq - request that is ready to be queued.
- * at_head - boolean. True if we should insert at head
- * of queue, false if we should insert at tail.
- *
- * Lock status: Assumed that lock is not held upon entry.
- *
- * Returns: Nothing
- *
- * Notes: This function is called from character device and from
- * ioctl types of functions where the caller knows exactly
- * what SCSI command needs to be issued. The idea is that
- * we merely inject the command into the queue (at the head
- * for now), and then call the queue request function to actually
- * process it.
- */
-int scsi_insert_special_req(struct scsi_request *sreq, int at_head)
-{
- /*
- * Because users of this function are apt to reuse requests with no
- * modification, we have to sanitise the request flags here
- */
- sreq->sr_request->flags &= ~REQ_DONTPREP;
- blk_insert_request(sreq->sr_device->request_queue, sreq->sr_request,
- at_head, sreq);
- return 0;
-}
-
static void scsi_run_queue(struct request_queue *q);
/*
@@ -249,8 +216,13 @@
/*
* head injection *required* here otherwise quiesce won't work
+ *
+ * Because users of this function are apt to reuse requests with no
+ * modification, we have to sanitise the request flags here
*/
- scsi_insert_special_req(sreq, 1);
+ sreq->sr_request->flags &= ~REQ_DONTPREP;
+ blk_insert_request(sreq->sr_device->request_queue, sreq->sr_request,
+ 1, sreq);
}
EXPORT_SYMBOL(scsi_do_req);
@@ -327,6 +299,196 @@
}
EXPORT_SYMBOL(scsi_execute_req);
+struct scsi_io_context {
+ void *data;
+ void (*done)(void *data, char *sense, int result, int resid);
+ char sense[SCSI_SENSE_BUFFERSIZE];
+};
+
+static void scsi_end_async(struct request *req)
+{
+ struct scsi_io_context *sioc = req->end_io_data;
+
+ if (sioc->done)
+ sioc->done(sioc->data, sioc->sense, req->errors, req->data_len);
+
+ kfree(sioc);
+ __blk_put_request(req->q, req);
+}
+
+static int scsi_merge_bio(struct request *rq, struct bio *bio)
+{
+ struct request_queue *q = rq->q;
+
+ bio->bi_flags &= ~(1 << BIO_SEG_VALID);
+ if (rq_data_dir(rq) == WRITE)
+ bio->bi_rw |= (1 << BIO_RW);
+ blk_queue_bounce(q, &bio);
+
+ if (!rq->bio)
+ blk_rq_bio_prep(q, rq, bio);
+ else if (!q->back_merge_fn(q, rq, bio))
+ return -EINVAL;
+ else {
+ rq->biotail->bi_next = bio;
+ rq->biotail = bio;
+ rq->hard_nr_sectors += bio_sectors(bio);
+ rq->nr_sectors = rq->hard_nr_sectors;
+ }
+
+ return 0;
+}
+
+static int scsi_bi_endio(struct bio *bio, unsigned int bytes_done, int error)
+{
+ if (bio->bi_size)
+ return 1;
+
+ bio_put(bio);
+ return 0;
+}
+
+/**
+ * scsi_req_map_sg - map a scatterlist into a request
+ * @rq: request to fill
+ * @sg: scatterlist
+ * @nsegs: number of elements
+ * @bufflen: len of buffer
+ * @gfp: memory allocation flags
+ *
+ * scsi_req_map_sg maps a scatterlist into a request so that the
+ * request can be sent to the block layer. We do not trust the scatterlist
+ * sent to use, as some ULDs use that struct to only organize the pages.
+ */
+static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl,
+ int nsegs, unsigned bufflen, gfp_t gfp)
+{
+ struct request_queue *q = rq->q;
+ int nr_pages = (bufflen + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ unsigned int data_len = 0, len, bytes, off;
+ struct page *page;
+ struct bio *bio = NULL;
+ int i, err, nr_vecs = 0;
+
+ for (i = 0; i < nsegs; i++) {
+ page = sgl[i].page;
+ off = sgl[i].offset;
+ len = sgl[i].length;
+ data_len += len;
+
+ while (len > 0) {
+ bytes = min_t(unsigned int, len, PAGE_SIZE - off);
+
+ if (!bio) {
+ nr_vecs = min_t(int, BIO_MAX_PAGES, nr_pages);
+ nr_pages -= nr_vecs;
+
+ bio = bio_alloc(gfp, nr_vecs);
+ if (!bio) {
+ err = -ENOMEM;
+ goto free_bios;
+ }
+ bio->bi_end_io = scsi_bi_endio;
+ }
+
+ if (bio_add_pc_page(q, bio, page, bytes, off) !=
+ bytes) {
+ bio_put(bio);
+ err = -EINVAL;
+ goto free_bios;
+ }
+
+ if (bio->bi_vcnt >= nr_vecs) {
+ err = scsi_merge_bio(rq, bio);
+ if (err) {
+ bio_endio(bio, bio->bi_size, 0);
+ goto free_bios;
+ }
+ bio = NULL;
+ }
+
+ page++;
+ len -= bytes;
+ off = 0;
+ }
+ }
+
+ rq->buffer = rq->data = NULL;
+ rq->data_len = data_len;
+ return 0;
+
+free_bios:
+ while ((bio = rq->bio) != NULL) {
+ rq->bio = bio->bi_next;
+ /*
+ * call endio instead of bio_put incase it was bounced
+ */
+ bio_endio(bio, bio->bi_size, 0);
+ }
+
+ return err;
+}
+
+/**
+ * scsi_execute_async - insert request
+ * @sdev: scsi device
+ * @cmd: scsi command
+ * @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
+ **/
+int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd,
+ int data_direction, void *buffer, unsigned bufflen,
+ int use_sg, int timeout, int retries, void *privdata,
+ void (*done)(void *, char *, int, int), gfp_t gfp)
+{
+ struct request *req;
+ struct scsi_io_context *sioc;
+ int err = 0;
+ int write = (data_direction == DMA_TO_DEVICE);
+
+ sioc = kzalloc(sizeof(*sioc), gfp);
+ if (!sioc)
+ return DRIVER_ERROR << 24;
+
+ req = blk_get_request(sdev->request_queue, write, gfp);
+ if (!req)
+ goto free_sense;
+
+ 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;
+
+ req->cmd_len = COMMAND_SIZE(cmd[0]);
+ memcpy(req->cmd, cmd, req->cmd_len);
+ req->sense = sioc->sense;
+ req->sense_len = 0;
+ req->timeout = timeout;
+ req->flags |= REQ_BLOCK_PC | REQ_QUIET;
+ req->end_io_data = sioc;
+
+ sioc->data = privdata;
+ sioc->done = done;
+
+ blk_execute_rq_nowait(req->q, NULL, req, 1, scsi_end_async);
+ return 0;
+
+free_req:
+ blk_put_request(req);
+free_sense:
+ kfree(sioc);
+ return DRIVER_ERROR << 24;
+}
+EXPORT_SYMBOL_GPL(scsi_execute_async);
+
/*
* Function: scsi_init_cmd_errh()
*
diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h
index a8d121c..f04e7e1 100644
--- a/drivers/scsi/scsi_priv.h
+++ b/drivers/scsi/scsi_priv.h
@@ -40,7 +40,6 @@
extern int scsi_dispatch_cmd(struct scsi_cmnd *cmd);
extern int scsi_setup_command_freelist(struct Scsi_Host *shost);
extern void scsi_destroy_command_freelist(struct Scsi_Host *shost);
-extern int scsi_insert_special_req(struct scsi_request *sreq, int);
extern void scsi_init_cmd_from_req(struct scsi_cmnd *cmd,
struct scsi_request *sreq);
extern void __scsi_release_request(struct scsi_request *sreq);
diff --git a/fs/bio.c b/fs/bio.c
index 460554b..4d21ee3 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -386,6 +386,25 @@
}
/**
+ * bio_add_pc_page - attempt to add page to bio
+ * @bio: destination bio
+ * @page: page to add
+ * @len: vec entry length
+ * @offset: vec entry offset
+ *
+ * Attempt to add a page to the bio_vec maplist. This can fail for a
+ * number of reasons, such as the bio being full or target block
+ * device limitations. The target block device must allow bio's
+ * smaller than PAGE_SIZE, so it is always possible to add a single
+ * page to an empty bio. This should only be used by REQ_PC bios.
+ */
+int bio_add_pc_page(request_queue_t *q, struct bio *bio, struct page *page,
+ unsigned int len, unsigned int offset)
+{
+ return __bio_add_page(q, bio, page, len, offset);
+}
+
+/**
* bio_add_page - attempt to add page to bio
* @bio: destination bio
* @page: page to add
@@ -1228,6 +1247,7 @@
EXPORT_SYMBOL(bio_phys_segments);
EXPORT_SYMBOL(bio_hw_segments);
EXPORT_SYMBOL(bio_add_page);
+EXPORT_SYMBOL(bio_add_pc_page);
EXPORT_SYMBOL(bio_get_nr_vecs);
EXPORT_SYMBOL(bio_map_user);
EXPORT_SYMBOL(bio_unmap_user);
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 685fd37..b60ffe3 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -292,6 +292,8 @@
extern void bio_init(struct bio *);
extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
+extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
+ unsigned int, unsigned int);
extern int bio_get_nr_vecs(struct block_device *);
extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
unsigned long, unsigned int, int);
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 063e32f..e94ca4d 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -274,6 +274,12 @@
extern int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd,
int data_direction, void *buffer, unsigned bufflen,
struct scsi_sense_hdr *, int timeout, int retries);
+extern int scsi_execute_async(struct scsi_device *sdev,
+ const unsigned char *cmd, int data_direction,
+ void *buffer, unsigned bufflen, int use_sg,
+ int timeout, int retries, void *privdata,
+ void (*done)(void *, char *, int, int),
+ gfp_t gfp);
static inline unsigned int sdev_channel(struct scsi_device *sdev)
{