This is a note to let you know that I've just added the patch titled
3w-9xxx: don't unmap bounce buffered commands
to the 4.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
3w-9xxx-don-t-unmap-bounce-buffered-commands.patch
and it can be found in the queue-4.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 15e3d5a285ab9283136dba34bbf72886d9146706 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@xxxxxx>
Date: Sat, 3 Oct 2015 19:16:07 +0200
Subject: 3w-9xxx: don't unmap bounce buffered commands
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Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
From: Christoph Hellwig <hch@xxxxxx>
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@xxxxxxxxxxxxx>
Tested-by: Tóth Attila <atoth@xxxxxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Acked-by: Adam Radford <aradford@xxxxxxxxx>
Signed-off-by: James Bottomley <JBottomley@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/scsi/3w-9xxx.c | 28 +++++++++++++++++++++-------
1 file changed, 21 insertions(+), 7 deletions(-)
--- a/drivers/scsi/3w-9xxx.c
+++ b/drivers/scsi/3w-9xxx.c
@@ -212,6 +212,17 @@ static const struct file_operations twa_
.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
}
/* 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
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 scs
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_De
/* 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_comp
{
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) {
Patches currently in stable-queue which might be from hch@xxxxxx are
queue-4.2/3w-9xxx-don-t-unmap-bounce-buffered-commands.patch
queue-4.2/nfs-fix-pg_test-page-count-calculation.patch
queue-4.2/target-attach-extended_copy-local-i-o-descriptors-to-xcopy_pt_sess.patch
queue-4.2/target-fix-pr-registration-aptpl-rcu-conversion-regression.patch
queue-4.2/blk-mq-avoid-setting-hctx-tags-cpumask-before-allocation.patch
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