libata: simplify ata_scsi_rbuf_fill()

Sparse complains about context imbalance in ata_scsi_rbuf_get() and
ata_scsi_rbuf_put() due to these functions respectively only taking
and releasing the ata_scsi_rbuf_lock spinlock. Since these functions are
only called from ata_scsi_rbuf_fill() with ata_scsi_rbuf_get() being
called with a copy_in argument always false, the code can be simplified
and ata_scsi_rbuf_{get|put} removed. This change both simplifies the
code and fixes the sparse warning.
Signed-off-by: NDamien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20210816014456.2191776-4-damien.lemoal@wdc.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

drivers/ata/libata-scsi.c

@@ -1765,53 +1765,6 @@ struct ata_scsi_args {
 	struct scsi_cmnd	*cmd;
 };
 
-/**
- *	ata_scsi_rbuf_get - Map response buffer.
- *	@cmd: SCSI command containing buffer to be mapped.
- *	@flags: unsigned long variable to store irq enable status
- *	@copy_in: copy in from user buffer
- *
- *	Prepare buffer for simulated SCSI commands.
- *
- *	LOCKING:
- *	spin_lock_irqsave(ata_scsi_rbuf_lock) on success
- *
- *	RETURNS:
- *	Pointer to response buffer.
- */
-static void *ata_scsi_rbuf_get(struct scsi_cmnd *cmd, bool copy_in,
-			       unsigned long *flags)
-{
-	spin_lock_irqsave(&ata_scsi_rbuf_lock, *flags);
-
-	memset(ata_scsi_rbuf, 0, ATA_SCSI_RBUF_SIZE);
-	if (copy_in)
-		sg_copy_to_buffer(scsi_sglist(cmd), scsi_sg_count(cmd),
-				  ata_scsi_rbuf, ATA_SCSI_RBUF_SIZE);
-	return ata_scsi_rbuf;
-}
-
-/**
- *	ata_scsi_rbuf_put - Unmap response buffer.
- *	@cmd: SCSI command containing buffer to be unmapped.
- *	@copy_out: copy out result
- *	@flags: @flags passed to ata_scsi_rbuf_get()
- *
- *	Returns rbuf buffer.  The result is copied to @cmd's buffer if
- *	@copy_back is true.
- *
- *	LOCKING:
- *	Unlocks ata_scsi_rbuf_lock.
- */
-static inline void ata_scsi_rbuf_put(struct scsi_cmnd *cmd, bool copy_out,
-				     unsigned long *flags)
-{
-	if (copy_out)
-		sg_copy_from_buffer(scsi_sglist(cmd), scsi_sg_count(cmd),
-				    ata_scsi_rbuf, ATA_SCSI_RBUF_SIZE);
-	spin_unlock_irqrestore(&ata_scsi_rbuf_lock, *flags);
-}
-
 /**
  *	ata_scsi_rbuf_fill - wrapper for SCSI command simulators
  *	@args: device IDENTIFY data / SCSI command of interest.
@@ -1830,14 +1783,19 @@ static inline void ata_scsi_rbuf_put(struct scsi_cmnd *cmd, bool copy_out,
 static void ata_scsi_rbuf_fill(struct ata_scsi_args *args,
 		unsigned int (*actor)(struct ata_scsi_args *args, u8 *rbuf))
 {
-	u8 *rbuf;
 	unsigned int rc;
 	struct scsi_cmnd *cmd = args->cmd;
 	unsigned long flags;
 
-	rbuf = ata_scsi_rbuf_get(cmd, false, &flags);
-	rc = actor(args, rbuf);
-	ata_scsi_rbuf_put(cmd, rc == 0, &flags);
+	spin_lock_irqsave(&ata_scsi_rbuf_lock, flags);
+
+	memset(ata_scsi_rbuf, 0, ATA_SCSI_RBUF_SIZE);
+	rc = actor(args, ata_scsi_rbuf);
+	if (rc == 0)
+		sg_copy_from_buffer(scsi_sglist(cmd), scsi_sg_count(cmd),
+				    ata_scsi_rbuf, ATA_SCSI_RBUF_SIZE);
+
+	spin_unlock_irqrestore(&ata_scsi_rbuf_lock, flags);
 
 	if (rc == 0)
 		cmd->result = SAM_STAT_GOOD;