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Commit 15e3d5a2 authored Oct 03, 2015 by Christoph Hellwig Committed by James Bottomley Oct 07, 2015

3w-9xxx: don't unmap bounce buffered commands



3w controller don't dma map small single SGL entry commands but instead
bounce buffer them.  Add a helper to identify these commands and don't
call scsi_dma_unmap for them.

Based on an earlier patch from James Bottomley.

Fixes: 118c85 ("3w-9xxx: fix command completion race")
Reported-by: Tóth Attila <atoth@atoth.sote.hu>
Tested-by: Tóth Attila <atoth@atoth.sote.hu>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Adam Radford <aradford@gmail.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>

parent 1378889c

drivers/scsi/3w-9xxx.c

+21 −7

Original line number	Diff line number	Diff line
		@@ -212,6 +212,17 @@ static const struct file_operations twa_fops = {
		.llseek = noop_llseek,
		};

		/*
		* The controllers use an inline buffer instead of a mapped SGL for small,
		* single entry buffers. Note that we treat a zero-length transfer like
		* a mapped SGL.
		*/
		static bool twa_command_mapped(struct scsi_cmnd *cmd)
		{
		return scsi_sg_count(cmd) != 1 \|\|
		scsi_bufflen(cmd) >= TW_MIN_SGL_LENGTH;
		}

		/* This function will complete an aen request from the isr */
		static int twa_aen_complete(TW_Device_Extension *tw_dev, int request_id)
		{
		@@ -1339,6 +1350,7 @@ static irqreturn_t twa_interrupt(int irq, void *dev_instance)
		}

		/* Now complete the io */
		if (twa_command_mapped(cmd))
		scsi_dma_unmap(cmd);
		cmd->scsi_done(cmd);
		tw_dev->state[request_id] = TW_S_COMPLETED;
		@@ -1582,6 +1594,7 @@ static int twa_reset_device_extension(TW_Device_Extension *tw_dev)
		struct scsi_cmnd *cmd = tw_dev->srb[i];

		cmd->result = (DID_RESET << 16);
		if (twa_command_mapped(cmd))
		scsi_dma_unmap(cmd);
		cmd->scsi_done(cmd);
		}
		@@ -1765,11 +1778,13 @@ static int twa_scsi_queue_lck(struct scsi_cmnd SCpnt, void (done)(struct scsi_
		retval = twa_scsiop_execute_scsi(tw_dev, request_id, NULL, 0, NULL);
		switch (retval) {
		case SCSI_MLQUEUE_HOST_BUSY:
		if (twa_command_mapped(SCpnt))
		scsi_dma_unmap(SCpnt);
		twa_free_request_id(tw_dev, request_id);
		break;
		case 1:
		SCpnt->result = (DID_ERROR << 16);
		if (twa_command_mapped(SCpnt))
		scsi_dma_unmap(SCpnt);
		done(SCpnt);
		tw_dev->state[request_id] = TW_S_COMPLETED;
		@@ -1831,8 +1846,7 @@ static int twa_scsiop_execute_scsi(TW_Device_Extension *tw_dev, int request_id,
		/* Map sglist from scsi layer to cmd packet */

		if (scsi_sg_count(srb)) {
		if ((scsi_sg_count(srb) == 1) &&
		(scsi_bufflen(srb) < TW_MIN_SGL_LENGTH)) {
		if (!twa_command_mapped(srb)) {
		if (srb->sc_data_direction == DMA_TO_DEVICE \|\|
		srb->sc_data_direction == DMA_BIDIRECTIONAL)
		scsi_sg_copy_to_buffer(srb,
		@@ -1905,7 +1919,7 @@ static void twa_scsiop_execute_scsi_complete(TW_Device_Extension *tw_dev, int re
		{
		struct scsi_cmnd *cmd = tw_dev->srb[request_id];

		if (scsi_bufflen(cmd) < TW_MIN_SGL_LENGTH &&
		if (!twa_command_mapped(cmd) &&
		(cmd->sc_data_direction == DMA_FROM_DEVICE \|\|
		cmd->sc_data_direction == DMA_BIDIRECTIONAL)) {
		if (scsi_sg_count(cmd) == 1) {