scsi: esp_scsi: Track residual for PIO transfers

[ Upstream commit fd47d919d0c336e7c22862b51ee94927ffea227a ]

If a target disconnects during a PIO data transfer the command may fail
when the target reconnects:

scsi host1: DMA length is zero!
scsi host1: cur adr[04380000] len[00000000]

The scsi bus is then reset. This happens because the residual reached
zero before the transfer was completed.

The usual residual calculation relies on the Transfer Count registers.
That works for DMA transfers but not for PIO transfers. Fix the problem
by storing the PIO transfer residual and using that to correctly
calculate bytes_sent.

Fixes: 6fe07aaffbf0 ("[SCSI] m68k: new mac_esp scsi driver")
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/scsi/esp_scsi.c b/drivers/scsi/esp_scsi.c
index 55548dc5cec39da14ec4b23c33ae4d1a609d30e6..cc674370b4b031633c5e373f9366681f2aca9863 100644 (file)
--- a/drivers/scsi/esp_scsi.c
+++ b/drivers/scsi/esp_scsi.c
@@ -1316,6 +1316,7 @@ static int esp_data_bytes_sent(struct esp *esp, struct esp_cmd_entry *ent,
 
        bytes_sent = esp->data_dma_len;
        bytes_sent -= ecount;
+       bytes_sent -= esp->send_cmd_residual;
 
        if (!(ent->flags & ESP_CMD_FLAG_WRITE))
                bytes_sent -= fifo_cnt;

diff --git a/drivers/scsi/esp_scsi.h b/drivers/scsi/esp_scsi.h
index cd68805e8d787e1d2ca9acaedd667d87bc201eb7..20b229b53639cf24321ddf60d896c389ba0532a9 100644 (file)
--- a/drivers/scsi/esp_scsi.h
+++ b/drivers/scsi/esp_scsi.h
@@ -524,6 +524,8 @@ struct esp {
 
        void                    *dma;
        int                     dmarev;
+
+       u32                     send_cmd_residual;
 };
 
 /* A front-end driver for the ESP chip should do the following in

diff --git a/drivers/scsi/mac_esp.c b/drivers/scsi/mac_esp.c
index 79fb6a4f661f8461e2508874252c37c9c71066ae..ec9d1a7f3daddfa5dfa58296970d26f03a7d35b1 100644 (file)
--- a/drivers/scsi/mac_esp.c
+++ b/drivers/scsi/mac_esp.c
@@ -426,6 +426,8 @@ static void mac_esp_send_pio_cmd(struct esp *esp, u32 addr, u32 esp_count,
                        scsi_esp_cmd(esp, ESP_CMD_TI);
                }
        }
+
+       esp->send_cmd_residual = esp_count;
 }
 
 static int mac_esp_irq_pending(struct esp *esp)