block/swim: Fix IO error at end of medium

Reading to the end of a 720K disk results in an IO error instead of EOF
because the block layer thinks the disk has 2880 sectors. (Partly this
is a result of inverted logic of the ONEMEG_MEDIA bit that's now fixed.)

Initialize the density and head count in swim_add_floppy() to agree
with the device size passed to set_capacity() during drive probe.

Call set_capacity() again upon device open, after refreshing the density
and head count values.

Cc: Laurent Vivier <lvivier@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: stable@vger.kernel.org # v4.14+
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Acked-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 8 insertions, 5 deletions

diff --git a/drivers/block/swim.c b/drivers/block/swim.c
index c8c8b9da3edd..2c75761b61e8 100644
--- a/drivers/block/swim.c
+++ b/drivers/block/swim.c
@@ -612,7 +612,6 @@ static void setup_medium(struct floppy_state *fs)
                 struct floppy_struct *g;
                 fs->disk_in = 1;
                 fs->write_protected = swim_readbit(base, WRITE_PROT);
-                fs->type = swim_readbit(base, TWOMEG_MEDIA);
 
                 if (swim_track00(base))
                         printk(KERN_ERR
@@ -620,6 +619,9 @@ static void setup_medium(struct floppy_state *fs)
 
                 swim_track00(base);
 
+                fs->type = swim_readbit(base, TWOMEG_MEDIA) ?
+                        HD_MEDIA : DD_MEDIA;
+                fs->head_number = swim_readbit(base, SINGLE_SIDED) ? 1 : 2;
                 get_floppy_geometry(fs, 0, &g);
                 fs->total_secs = g->size;
                 fs->secpercyl = g->head * g->sect;
@@ -656,6 +658,8 @@ static int floppy_open(struct block_device *bdev, fmode_t mode)
                 goto out;
         }
 
+        set_capacity(fs->disk, fs->total_secs);
+
         if (mode & FMODE_NDELAY)
                 return 0;
 
@@ -808,10 +812,9 @@ static int swim_add_floppy(struct swim_priv *swd, enum drive_location location)
 
         swim_motor(base, OFF);
 
-        if (swim_readbit(base, SINGLE_SIDED))
-                fs->head_number = 1;
-        else
-                fs->head_number = 2;
+        fs->type = HD_MEDIA;
+        fs->head_number = 2;
+
         fs->ref_count = 0;
         fs->ejected = 1;