[S390] vmur: diag14 only works with buffers below 2GB

If memory buffers above 2GB are used, diagnose 14 raises a specification
exception. This fix ensures that buffer allocation is done below the 2GB
boundary.

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

diff --git a/drivers/s390/char/vmur.c b/drivers/s390/char/vmur.c
index a9d5862..04b19bd 100644 (file)
--- a/drivers/s390/char/vmur.c
+++ b/drivers/s390/char/vmur.c
@@ -472,7 +472,7 @@ static ssize_t diag14_read(struct file *file, char __user *ubuf, size_t count,
                return rc;
 
        len = min((size_t) PAGE_SIZE, count);
-       buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+       buf = (char *) __get_free_page(GFP_KERNEL | GFP_DMA);
        if (!buf)
                return -ENOMEM;
 
@@ -499,7 +499,7 @@ static ssize_t diag14_read(struct file *file, char __user *ubuf, size_t count,
        *offs += copied;
        rc = copied;
 fail:
-       kfree(buf);
+       free_page((unsigned long) buf);
        return rc;
 }
 
@@ -542,63 +542,97 @@ static int diag_read_next_file_info(struct file_control_block *buf, int spid)
        }
 }
 
-static int verify_device(struct urdev *urd)
+static int verify_uri_device(struct urdev *urd)
 {
-       struct file_control_block fcb;
+       struct file_control_block *fcb;
        char *buf;
        int rc;
 
+       fcb = kmalloc(sizeof(*fcb), GFP_KERNEL | GFP_DMA);
+       if (!fcb)
+               return -ENOMEM;
+
+       /* check for empty reader device (beginning of chain) */
+       rc = diag_read_next_file_info(fcb, 0);
+       if (rc)
+               goto fail_free_fcb;
+
+       /* if file is in hold status, we do not read it */
+       if (fcb->file_stat & (FLG_SYSTEM_HOLD | FLG_USER_HOLD)) {
+               rc = -EPERM;
+               goto fail_free_fcb;
+       }
+
+       /* open file on virtual reader  */
+       buf = (char *) __get_free_page(GFP_KERNEL | GFP_DMA);
+       if (!buf) {
+               rc = -ENOMEM;
+               goto fail_free_fcb;
+       }
+       rc = diag_read_file(urd->dev_id.devno, buf);
+       if ((rc != 0) && (rc != -ENODATA)) /* EOF does not hurt */
+               goto fail_free_buf;
+
+       /* check if the file on top of the queue is open now */
+       rc = diag_read_next_file_info(fcb, 0);
+       if (rc)
+               goto fail_free_buf;
+       if (!(fcb->file_stat & FLG_IN_USE)) {
+               rc = -EMFILE;
+               goto fail_free_buf;
+       }
+       rc = 0;
+
+fail_free_buf:
+       free_page((unsigned long) buf);
+fail_free_fcb:
+       kfree(fcb);
+       return rc;
+}
+
+static int verify_device(struct urdev *urd)
+{
        switch (urd->class) {
        case DEV_CLASS_UR_O:
                return 0; /* no check needed here */
        case DEV_CLASS_UR_I:
-               /* check for empty reader device (beginning of chain) */
-               rc = diag_read_next_file_info(&fcb, 0);
-               if (rc)
-                       return rc;
-               /* if file is in hold status, we do not read it */
-               if (fcb.file_stat & (FLG_SYSTEM_HOLD | FLG_USER_HOLD))
-                       return -EPERM;
-               /* open file on virtual reader  */
-               buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
-               if (!buf)
-                       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;
+               return verify_uri_device(urd);
        default:
                return -ENOTSUPP;
        }
 }
 
-static int get_file_reclen(struct urdev *urd)
+static int get_uri_file_reclen(struct urdev *urd)
 {
-       struct file_control_block fcb;
+       struct file_control_block *fcb;
        int rc;
 
+       fcb = kmalloc(sizeof(*fcb), GFP_KERNEL | GFP_DMA);
+       if (!fcb)
+               return -ENOMEM;
+       rc = diag_read_next_file_info(fcb, 0);
+       if (rc)
+               goto fail_free;
+       if (fcb->file_stat & FLG_CP_DUMP)
+               rc = 0;
+       else
+               rc = fcb->rec_len;
+
+fail_free:
+       kfree(fcb);
+       return rc;
+}
+
+static int get_file_reclen(struct urdev *urd)
+{
        switch (urd->class) {
        case DEV_CLASS_UR_O:
                return 0;
        case DEV_CLASS_UR_I:
-               rc = diag_read_next_file_info(&fcb, 0);
-               if (rc)
-                       return rc;
-               break;
+               return get_uri_file_reclen(urd);
        default:
                return -ENOTSUPP;
        }
-       if (fcb.file_stat & FLG_CP_DUMP)
-               return 0;
-
-       return fcb.rec_len;
 }
 
 static int ur_open(struct inode *inode, struct file *file)