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authorChristoph Hellwig <hch@lst.de>2015-10-03 19:16:07 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-10-22 14:43:27 -0700
commitbaf19f15c8d54395b338a34004ff1f0c1d7c15e7 (patch)
tree53cae67ac449f8c67820b5cdb66c2b9d6e207551
parenta8ef8d4e5bbc5035a1e9789592ca7e8db09c2ea8 (diff)
3w-9xxx: don't unmap bounce buffered commands
commit 15e3d5a285ab9283136dba34bbf72886d9146706 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/scsi/3w-9xxx.c28
1 files changed, 21 insertions, 7 deletions
diff --git a/drivers/scsi/3w-9xxx.c b/drivers/scsi/3w-9xxx.c
index add419d6ff34..a56a7b243e91 100644
--- a/drivers/scsi/3w-9xxx.c
+++ b/drivers/scsi/3w-9xxx.c
@@ -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)
{
@@ -1339,7 +1350,8 @@ static irqreturn_t twa_interrupt(int irq, void *dev_instance)
}
/* Now complete the io */
- scsi_dma_unmap(cmd);
+ if (twa_command_mapped(cmd))
+ scsi_dma_unmap(cmd);
cmd->scsi_done(cmd);
tw_dev->state[request_id] = TW_S_COMPLETED;
twa_free_request_id(tw_dev, request_id);
@@ -1582,7 +1594,8 @@ static int twa_reset_device_extension(TW_Device_Extension *tw_dev)
struct scsi_cmnd *cmd = tw_dev->srb[i];
cmd->result = (DID_RESET << 16);
- scsi_dma_unmap(cmd);
+ if (twa_command_mapped(cmd))
+ scsi_dma_unmap(cmd);
cmd->scsi_done(cmd);
}
}
@@ -1765,12 +1778,14 @@ 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:
- scsi_dma_unmap(SCpnt);
+ 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);
- scsi_dma_unmap(SCpnt);
+ if (twa_command_mapped(SCpnt))
+ scsi_dma_unmap(SCpnt);
done(SCpnt);
tw_dev->state[request_id] = TW_S_COMPLETED;
twa_free_request_id(tw_dev, request_id);
@@ -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) {