ide-{floppy,tape}: fix padding for PIO transfers

* Return number of bytes left to transfer from idetape_{in,out}put_buffers()
  and number of bytes done from ide_tape_io_buffers().

* Fix padding for PIO transfers in ide_pc_intr() so read/write buffers are
  always completely processed and then the transfer is padded if necessary.

* Remove invalid error messages.

* Remove now superfluous padding from ide{_io_buffers,tape_input_buffers}().

While at it:

* Set pc->bh to NULL in idetape_input_buffers() after all bh-s are done.

* Cache !!(pc->flags & PC_FLAG_WRITING) in local variable in ide_pc_intr().

Cc: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

2 files changed, 35 insertions, 54 deletions

diff --git a/drivers/ide/ide-atapi.c b/drivers/ide/ide-atapi.c
index 3f3fc7c7b2fe..40f413b20bd8 100644
--- a/drivers/ide/ide-atapi.c
+++ b/drivers/ide/ide-atapi.c
@@ -110,13 +110,6 @@ int ide_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
                 }
         }
 
-        if (bcount) {
-                printk(KERN_ERR "%s: %d leftover bytes, %s\n", drive->name,
-                        bcount, write ? "padding with zeros"
-                                      : "discarding data");
-                ide_pad_transfer(drive, write, bcount);
-        }
-
         return done;
 }
 EXPORT_SYMBOL_GPL(ide_io_buffers);
@@ -330,9 +323,10 @@ static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
         struct request *rq = hwif->rq;
         const struct ide_tp_ops *tp_ops = hwif->tp_ops;
         xfer_func_t *xferfunc;
-        unsigned int timeout, temp;
+        unsigned int timeout, done;
         u16 bcount;
         u8 stat, ireason, dsc = 0;
+        u8 write = !!(pc->flags & PC_FLAG_WRITING);
 
         debug_log("Enter %s - interrupt handler\n", __func__);
 
@@ -441,8 +435,7 @@ static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
                 return ide_do_reset(drive);
         }
 
-        if (((ireason & ATAPI_IO) == ATAPI_IO) ==
-                !!(pc->flags & PC_FLAG_WRITING)) {
+        if (((ireason & ATAPI_IO) == ATAPI_IO) == write) {
                 /* Hopefully, we will never get here */
                 printk(KERN_ERR "%s: We wanted to %s, but the device wants us "
                                 "to %s!\n", drive->name,
@@ -451,45 +444,33 @@ static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
                 return ide_do_reset(drive);
         }
 
-        if (!(pc->flags & PC_FLAG_WRITING)) {
-                /* Reading - Check that we have enough space */
-                temp = pc->xferred + bcount;
-                if (temp > pc->req_xfer) {
-                        if (temp > pc->buf_size) {
-                                printk(KERN_ERR "%s: The device wants to send "
-                                                "us more data than expected - "
-                                                "discarding data\n",
-                                                drive->name);
-
-                                ide_pad_transfer(drive, 0, bcount);
-                                goto next_irq;
-                        }
-                        debug_log("The device wants to send us more data than "
-                                  "expected - allowing transfer\n");
-                }
-                xferfunc = tp_ops->input_data;
-        } else
-                xferfunc = tp_ops->output_data;
+        xferfunc = write ? tp_ops->output_data : tp_ops->input_data;
 
         if ((drive->media == ide_floppy && !pc->buf) ||
             (drive->media == ide_tape && pc->bh)) {
-                int done = drive->pc_io_buffers(drive, pc, bcount,
-                                  !!(pc->flags & PC_FLAG_WRITING));
+                done = drive->pc_io_buffers(drive, pc, bcount, write);
 
                 /* FIXME: don't do partial completions */
                 if (drive->media == ide_floppy)
                         ide_complete_rq(drive, 0,
                                         done ? done : ide_rq_bytes(rq));
-        } else
-                xferfunc(drive, NULL, pc->cur_pos, bcount);
+        } else {
+                done = min_t(unsigned int, bcount, pc->req_xfer - pc->xferred);
+                xferfunc(drive, NULL, pc->cur_pos, done);
+        }
 
         /* Update the current position */
-        pc->xferred += bcount;
-        pc->cur_pos += bcount;
+        pc->xferred += done;
+        pc->cur_pos += done;
+
+        bcount -= done;
+
+        if (bcount)
+                ide_pad_transfer(drive, write, bcount);
+
+        debug_log("[cmd %x] transferred %d bytes, padded %d bytes\n",
+                  rq->cmd[0], done, bcount);
 
-        debug_log("[cmd %x] transferred %d bytes on that intr.\n",
-                  rq->cmd[0], bcount);
-next_irq:
         /* And set the interrupt handler again */
         ide_set_handler(drive, ide_pc_intr, timeout);
         return ide_started;
diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
index cafc67d9e2e8..cb942a9b580f 100644
--- a/drivers/ide/ide-tape.c
+++ b/drivers/ide/ide-tape.c
@@ -297,19 +297,15 @@ static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
         return tape;
 }
 
-static void idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
+static int idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
                                   unsigned int bcount)
 {
         struct idetape_bh *bh = pc->bh;
         int count;
 
         while (bcount) {
-                if (bh == NULL) {
-                        printk(KERN_ERR "ide-tape: bh == NULL in "
-                                "idetape_input_buffers\n");
-                        ide_pad_transfer(drive, 0, bcount);
-                        return;
-                }
+                if (bh == NULL)
+                        break;
                 count = min(
                         (unsigned int)(bh->b_size - atomic_read(&bh->b_count)),
                         bcount);
@@ -323,21 +319,21 @@ static void idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
                                 atomic_set(&bh->b_count, 0);
                 }
         }
+
         pc->bh = bh;
+
+        return bcount;
 }
 
-static void idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
+static int idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
                                    unsigned int bcount)
 {
         struct idetape_bh *bh = pc->bh;
         int count;
 
         while (bcount) {
-                if (bh == NULL) {
-                        printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
-                                        __func__);
-                        return;
-                }
+                if (bh == NULL)
+                        break;
                 count = min((unsigned int)pc->b_count, (unsigned int)bcount);
                 drive->hwif->tp_ops->output_data(drive, NULL, pc->b_data, count);
                 bcount -= count;
@@ -352,6 +348,8 @@ static void idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
                         }
                 }
         }
+
+        return bcount;
 }
 
 static void idetape_update_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc)
@@ -563,12 +561,14 @@ static void ide_tape_handle_dsc(ide_drive_t *drive)
 static int ide_tape_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
                                 unsigned int bcount, int write)
 {
+        unsigned int bleft;
+
         if (write)
-                idetape_output_buffers(drive, pc, bcount);
+                bleft = idetape_output_buffers(drive, pc, bcount);
         else
-                idetape_input_buffers(drive, pc, bcount);
+                bleft = idetape_input_buffers(drive, pc, bcount);
 
-        return bcount;
+        return bcount - bleft;
 }
 
 /*