s390/tape: Move idal allocation to core functions

Currently tapechar_check_idalbuffer() is part of tape_char.c and is used
to ensure the idal buffer is big enough for the requested I/O and
reallocates a new one if required. The same is done in tape_std.c when a
fixed block size is set using the mtsetblk command. This is essentially
duplicate code.

The allocation of the buffer that is required for I/O can be considered
core functionality. Move the idal buffer allocation to tape_core.c,
make it generally available, and reduce code duplication.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

4 files changed, 35 insertions, 47 deletions

diff --git a/drivers/s390/char/tape.h b/drivers/s390/char/tape.h
index 0596a9758662..349fa95dcedb 100644
--- a/drivers/s390/char/tape.h
+++ b/drivers/s390/char/tape.h
@@ -234,6 +234,7 @@ struct tape_device {
 /* Externals from tape_core.c */
 extern struct tape_request *tape_alloc_request(int cplength, int datasize);
 extern void tape_free_request(struct tape_request *);
+extern int tape_check_idalbuffer(struct tape_device *device, size_t size);
 extern int tape_do_io(struct tape_device *, struct tape_request *);
 extern int tape_do_io_async(struct tape_device *, struct tape_request *);
 extern int tape_do_io_interruptible(struct tape_device *, struct tape_request *);
diff --git a/drivers/s390/char/tape_char.c b/drivers/s390/char/tape_char.c
index 3d557b55bda8..e229585cfb9e 100644
--- a/drivers/s390/char/tape_char.c
+++ b/drivers/s390/char/tape_char.c
@@ -93,33 +93,6 @@ tapechar_cleanup_device(struct tape_device *device)
 	device->nt = NULL;
 }
 
-static int
-tapechar_check_idalbuffer(struct tape_device *device, size_t block_size)
-{
-	struct idal_buffer *new;
-
-	if (device->char_data.idal_buf != NULL &&
-	    device->char_data.idal_buf->size == block_size)
-		return 0;
-
-	if (block_size > MAX_BLOCKSIZE) {
-		DBF_EVENT(3, "Invalid blocksize (%zd > %d)\n",
-			block_size, MAX_BLOCKSIZE);
-		return -EINVAL;
-	}
-
-	/* The current idal buffer is not correct. Allocate a new one. */
-	new = idal_buffer_alloc(block_size, 0);
-	if (IS_ERR(new))
-		return -ENOMEM;
-
-	if (device->char_data.idal_buf != NULL)
-		idal_buffer_free(device->char_data.idal_buf);
-
-	device->char_data.idal_buf = new;
-
-	return 0;
-}
 
 /*
  * Tape device read function
@@ -156,7 +129,7 @@ tapechar_read(struct file *filp, char __user *data, size_t count, loff_t *ppos)
 		block_size = count;
 	}
 
-	rc = tapechar_check_idalbuffer(device, block_size);
+	rc = tape_check_idalbuffer(device, block_size);
 	if (rc)
 		return rc;
 
@@ -208,7 +181,7 @@ tapechar_write(struct file *filp, const char __user *data, size_t count, loff_t
 		nblocks = 1;
 	}
 
-	rc = tapechar_check_idalbuffer(device, block_size);
+	rc = tape_check_idalbuffer(device, block_size);
 	if (rc)
 		return rc;
 
diff --git a/drivers/s390/char/tape_core.c b/drivers/s390/char/tape_core.c
index 6ec812280221..30ace31a3bba 100644
--- a/drivers/s390/char/tape_core.c
+++ b/drivers/s390/char/tape_core.c
@@ -726,6 +726,34 @@ tape_free_request (struct tape_request * request)
 	kfree(request);
 }
 
+int
+tape_check_idalbuffer(struct tape_device *device, size_t size)
+{
+	struct idal_buffer *new;
+
+	if (device->char_data.idal_buf != NULL &&
+	    device->char_data.idal_buf->size == size)
+		return 0;
+
+	if (size > MAX_BLOCKSIZE) {
+		DBF_EVENT(3, "Invalid blocksize (%zd > %d)\n",
+			  size, MAX_BLOCKSIZE);
+		return -EINVAL;
+	}
+
+	/* The current idal buffer is not correct. Allocate a new one. */
+	new = idal_buffer_alloc(size, 0);
+	if (IS_ERR(new))
+		return -ENOMEM;
+
+	if (device->char_data.idal_buf != NULL)
+		idal_buffer_free(device->char_data.idal_buf);
+
+	device->char_data.idal_buf = new;
+
+	return 0;
+}
+
 static int
 __tape_start_io(struct tape_device *device, struct tape_request *request)
 {
diff --git a/drivers/s390/char/tape_std.c b/drivers/s390/char/tape_std.c
index e46ffc46f323..29abbc23f908 100644
--- a/drivers/s390/char/tape_std.c
+++ b/drivers/s390/char/tape_std.c
@@ -212,7 +212,7 @@ tape_std_mtload(struct tape_device *device, int count)
 int
 tape_std_mtsetblk(struct tape_device *device, int count)
 {
-	struct idal_buffer *new;
+	int rc;
 
 	DBF_LH(6, "tape_std_mtsetblk(%d)\n", count);
 	if (count <= 0) {
@@ -224,26 +224,12 @@ tape_std_mtsetblk(struct tape_device *device, int count)
 		device->char_data.block_size = 0;
 		return 0;
 	}
-	if (device->char_data.idal_buf != NULL &&
-	    device->char_data.idal_buf->size == count)
-		/* We already have a idal buffer of that size. */
-		return 0;
 
-	if (count > MAX_BLOCKSIZE) {
-		DBF_EVENT(3, "Invalid block size (%d > %d) given.\n",
-			count, MAX_BLOCKSIZE);
-		return -EINVAL;
-	}
+	rc = tape_check_idalbuffer(device, count);
+	if (rc)
+		return rc;
 
-	/* Allocate a new idal buffer. */
-	new = idal_buffer_alloc(count, 0);
-	if (IS_ERR(new))
-		return -ENOMEM;
-	if (device->char_data.idal_buf != NULL)
-		idal_buffer_free(device->char_data.idal_buf);
-	device->char_data.idal_buf = new;
 	device->char_data.block_size = count;
-
 	DBF_LH(6, "new blocksize is %d\n", device->char_data.block_size);
 
 	return 0;