From 57589690d423150d4464d86b2f2be60aff93804e Mon Sep 17 00:00:00 2001 From: Finn Thain Date: Tue, 16 Oct 2018 16:31:25 +1100 Subject: [PATCH] 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 Signed-off-by: Finn Thain Tested-by: Michael Schmitz Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/scsi/esp_scsi.c | 1 + drivers/scsi/esp_scsi.h | 2 ++ drivers/scsi/mac_esp.c | 2 ++ 3 files changed, 5 insertions(+) diff --git a/drivers/scsi/esp_scsi.c b/drivers/scsi/esp_scsi.c index 71cb05b..60be074 100644 --- a/drivers/scsi/esp_scsi.c +++ b/drivers/scsi/esp_scsi.c @@ -1349,6 +1349,7 @@ 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; /* * The am53c974 has a DMA 'pecularity'. The doc states: diff --git a/drivers/scsi/esp_scsi.h b/drivers/scsi/esp_scsi.h index 84dcbe4..55be43f 100644 --- a/drivers/scsi/esp_scsi.h +++ b/drivers/scsi/esp_scsi.h @@ -540,6 +540,8 @@ 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 26c67c4..1002124 100644 --- 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) -- 2.7.4