diff options
| author | Christoph Hellwig <hch@lst.de> | 2015-10-03 19:16:07 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-10-22 14:37:53 -0700 |
| commit | c3dadb26a96bd1895a6ab69e0042a52014b7986a (patch) | |
| tree | 805582fac1c030f80b5748f5b293bfda21c7d557 | |
| parent | 613df159a3db2421407d69ba4473bf4830060347 (diff) | |
| download | lwn-c3dadb26a96bd1895a6ab69e0042a52014b7986a.tar.gz lwn-c3dadb26a96bd1895a6ab69e0042a52014b7986a.zip | |
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.c | 28 |
1 files changed, 21 insertions, 7 deletions
diff --git a/drivers/scsi/3w-9xxx.c b/drivers/scsi/3w-9xxx.c index 5f57e3d35e26..6adf9abdf955 100644 --- a/drivers/scsi/3w-9xxx.c +++ b/drivers/scsi/3w-9xxx.c @@ -225,6 +225,17 @@ 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) { @@ -1351,7 +1362,8 @@ 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); @@ -1594,7 +1606,8 @@ 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); } } @@ -1777,12 +1790,14 @@ 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); @@ -1843,8 +1858,7 @@ 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, @@ -1917,7 +1931,7 @@ 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) { |