[S390] vmur: add "top of queue" sanity check for reader open (4eac3452) · Commits · 戴 / test

If the z/VM reader is already open, it can happen that after opening the Linux reader device, not the topmost file is processed. According the semantics of the Linux z/VM unit record device driver, always the topmost file has to be processed. With this fix an error is returned if that is not the case. Signed-off-by:

Michael Holzheu <holzheu@de.ibm.com> Signed-off-by:

Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/char/vmur.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -565,9 +565,14 @@ static int verify_device(struct urdev *urd)
		return -ENOMEM;
		rc = diag_read_file(urd->dev_id.devno, buf);
		kfree(buf);

		if ((rc != 0) && (rc != -ENODATA)) /* EOF does not hurt */
		return rc;
		/* check if the file on top of the queue is open now */
		rc = diag_read_next_file_info(&fcb, 0);
		if (rc)
		return rc;
		if (!(fcb.file_stat & FLG_IN_USE))
		return -EMFILE;
		return 0;
		default:
		return -ENOTSUPP;

drivers/s390/char/vmur.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -53,6 +53,7 @@ struct file_control_block {
		#define FLG_SYSTEM_HOLD 0x04
		#define FLG_CP_DUMP 0x10
		#define FLG_USER_HOLD 0x20
		#define FLG_IN_USE 0x80

		/*
		* A struct urdev is created for each ur device that is made available

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