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

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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>
This commit is contained in:
Christoph Hellwig 2015-10-03 19:16:07 +02:00 committed by James Bottomley
parent 1378889c56
commit 15e3d5a285
1 changed files with 21 additions and 7 deletions
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20
drivers/scsi/3w-9xxx.c
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@ -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) {