[PATCH v18 60/83] sg: compress usercontext to uc

[Douglas Gilbert <dgilbert@interlog.com>]

Abbreviate sg_usercontext_* functions to start with sg_uc_ instead.
Rework associated function.

Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
---
 drivers/scsi/sg.c | 58 ++++++++++++++++++++++++-----------------------
 1 file changed, 30 insertions(+), 28 deletions(-)

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 045aa96addac..8e0ae40cde87 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -635,7 +635,7 @@ sg_fd_share_ptr(struct sg_fd *sfp)
  * Release resources associated with a prior, successful sg_open(). It can be
  * seen as the (final) close() call on a sg device file descriptor in the user
  * space. The real work releasing all resources associated with this file
- * descriptor is done by sg_remove_sfp_usercontext() which is scheduled by
+ * descriptor is done by sg_uc_remove_sfp() which is scheduled by
  * sg_remove_sfp().
  */
 static int
@@ -4630,24 +4630,25 @@ sg_mmap(struct file *filp, struct vm_area_struct *vma)
 	return res;
 }
 
+/*
+ * This user context function is called from sg_rq_end_io() when an orphaned
+ * request needs to be cleaned up (e.g. when control C is typed while an
+ * ioctl(SG_IO) is active).
+ */
 static void
-sg_rq_end_io_usercontext(struct work_struct *work)
+sg_uc_rq_end_io_orphaned(struct work_struct *work)
 {
 	struct sg_request *srp = container_of(work, struct sg_request,
 					      ew_orph.work);
 	struct sg_fd *sfp;
 
-	if (unlikely(!srp)) {
-		WARN_ONCE(1, "%s: srp unexpectedly NULL\n", __func__);
-		return;
-	}
 	sfp = srp->parentfp;
 	if (unlikely(!sfp)) {
 		WARN_ONCE(1, "%s: sfp unexpectedly NULL\n", __func__);
 		return;
 	}
 	SG_LOG(3, sfp, "%s: srp=0x%pK\n", __func__, srp);
-	if (unlikely(test_bit(SG_FRQ_DEACT_ORPHAN, srp->frq_bm))) {
+	if (test_bit(SG_FRQ_DEACT_ORPHAN, srp->frq_bm)) {
 		sg_finish_scsi_blk_rq(srp);	/* clean up orphan case */
 		sg_deact_request(sfp, srp);
 	}
@@ -4761,18 +4762,19 @@ sg_rq_end_io(struct request *rqq, blk_status_t status)
 	scsi_req_free_cmd(scsi_rp);
 	blk_put_request(rqq);
 
-	if (likely(rqq_state == SG_RQ_AWAIT_RCV)) {
-		/* Wake any sg_read()/ioctl(SG_IORECEIVE) awaiting this req */
-		if (!(srp->rq_flags & SGV4_FLAG_HIPRI))
-			wake_up_interruptible(&sfp->cmpl_wait);
-		if (sfp->async_qp && (!test_bit(SG_FRQ_IS_V4I, srp->frq_bm) ||
-				      (srp->rq_flags & SGV4_FLAG_SIGNAL)))
-			kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
-		kref_put(&sfp->f_ref, sg_remove_sfp);
-	} else {        /* clean up orphaned request that aren't being kept */
-		INIT_WORK(&srp->ew_orph.work, sg_rq_end_io_usercontext);
+	if (unlikely(rqq_state != SG_RQ_AWAIT_RCV)) {
+		/* clean up orphaned request that aren't being kept */
+		INIT_WORK(&srp->ew_orph.work, sg_uc_rq_end_io_orphaned);
 		schedule_work(&srp->ew_orph.work);
+		return;
 	}
+	/* Wake any sg_read()/ioctl(SG_IORECEIVE) awaiting this req */
+	if (!(srp->rq_flags & SGV4_FLAG_HIPRI))
+		wake_up_interruptible(&sfp->cmpl_wait);
+	if (sfp->async_qp && (!test_bit(SG_FRQ_IS_V4I, srp->frq_bm) ||
+			      (srp->rq_flags & SGV4_FLAG_SIGNAL)))
+		kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
+	kref_put(&sfp->f_ref, sg_remove_sfp);
 	return;
 }
 
@@ -6222,15 +6224,15 @@ sg_add_sfp(struct sg_device *sdp, struct file *filp)
 
 /*
  * A successful call to sg_release() will result, at some later time, to this
- * function being invoked. All requests associated with this file descriptor
- * should be completed or cancelled when this function is called (due to
- * sfp->f_ref). Also the file descriptor itself has not been accessible since
- * it was list_del()-ed by the preceding sg_remove_sfp() call. So no locking
- * is required. sdp should never be NULL but to make debugging more robust,
- * this function will not blow up in that case.
+ * "user context" function being invoked. All requests associated with this
+ * file descriptor should be completed or cancelled when this function is
+ * called (due to sfp->f_ref). Also the file descriptor itself has not been
+ * accessible since it was list_del()-ed by the preceding sg_remove_sfp()
+ * call. So no locking is required. sdp should never be NULL but to make
+ * debugging more robust, this function will not blow up in that case.
  */
 static void
-sg_remove_sfp_usercontext(struct work_struct *work)
+sg_uc_remove_sfp(struct work_struct *work)
 {
 	__maybe_unused int o_count;
 	int subm;
@@ -6295,7 +6297,7 @@ sg_remove_sfp(struct kref *kref)
 {
 	struct sg_fd *sfp = container_of(kref, struct sg_fd, f_ref);
 
-	INIT_WORK(&sfp->ew_fd.work, sg_remove_sfp_usercontext);
+	INIT_WORK(&sfp->ew_fd.work, sg_uc_remove_sfp);
 	schedule_work(&sfp->ew_fd.work);
 }
 
@@ -6342,11 +6344,11 @@ sg_rq_st_str(enum sg_rq_state rq_st, bool long_str)
 		return long_str ? "inflight" : "act";
 	case SG_RQ_AWAIT_RCV:
 		return long_str ? "await_receive" : "rcv";
-	case SG_RQ_BUSY:
+	case SG_RQ_BUSY:	/* state transitioning */
 		return long_str ? "busy" : "bsy";
-	case SG_RQ_SHR_SWAP:	/* only an active read-side has this */
+	case SG_RQ_SHR_SWAP:	/* read-side: awaiting write-side req start */
 		return long_str ? "share swap" : "s_wp";
-	case SG_RQ_SHR_IN_WS:	/* only an active read-side has this */
+	case SG_RQ_SHR_IN_WS:	/* read-side: waiting for inflight write-side */
 		return long_str ? "share write-side active" : "ws_a";
 	default:
 		return long_str ? "unknown" : "unk";
-- 
2.25.1