[PATCH 4.4 69/72] Revert "mtip32xx: use runtime tag to initialize command header"

From: Greg Kroah-Hartman
Date: Fri Apr 06 2018 - 10:55:26 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

This reverts commit 9bf9e352ed51d4cdee107675609ba12b42d00c5b which was
commit a4e84aae8139aca9fbfbced1f45c51ca81b57488 upstream.

Ben writes:
MQ IO schedulers were introduced in 4.11, so this shouldn't be
needed in older branches. It also causes a performance
regression (fixed upstream). Please revert this for 4.4 and
4.9.

So let's revert it!

Reported-by: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx>
Cc: Ming Lei <ming.lei@xxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxx>
Cc: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/block/mtip32xx/mtip32xx.c | 36 ++++++++++++------------------------
1 file changed, 12 insertions(+), 24 deletions(-)

--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -169,25 +169,6 @@ static bool mtip_check_surprise_removal(
return false; /* device present */
}

-/* we have to use runtime tag to setup command header */
-static void mtip_init_cmd_header(struct request *rq)
-{
- struct driver_data *dd = rq->q->queuedata;
- struct mtip_cmd *cmd = blk_mq_rq_to_pdu(rq);
- u32 host_cap_64 = readl(dd->mmio + HOST_CAP) & HOST_CAP_64;
-
- /* Point the command headers at the command tables. */
- cmd->command_header = dd->port->command_list +
- (sizeof(struct mtip_cmd_hdr) * rq->tag);
- cmd->command_header_dma = dd->port->command_list_dma +
- (sizeof(struct mtip_cmd_hdr) * rq->tag);
-
- if (host_cap_64)
- cmd->command_header->ctbau = __force_bit2int cpu_to_le32((cmd->command_dma >> 16) >> 16);
-
- cmd->command_header->ctba = __force_bit2int cpu_to_le32(cmd->command_dma & 0xFFFFFFFF);
-}
-
static struct mtip_cmd *mtip_get_int_command(struct driver_data *dd)
{
struct request *rq;
@@ -199,9 +180,6 @@ static struct mtip_cmd *mtip_get_int_com
if (IS_ERR(rq))
return NULL;

- /* Internal cmd isn't submitted via .queue_rq */
- mtip_init_cmd_header(rq);
-
return blk_mq_rq_to_pdu(rq);
}

@@ -3840,8 +3818,6 @@ static int mtip_queue_rq(struct blk_mq_h
struct request *rq = bd->rq;
int ret;

- mtip_init_cmd_header(rq);
-
if (unlikely(mtip_check_unal_depth(hctx, rq)))
return BLK_MQ_RQ_QUEUE_BUSY;

@@ -3873,6 +3849,7 @@ static int mtip_init_cmd(void *data, str
{
struct driver_data *dd = data;
struct mtip_cmd *cmd = blk_mq_rq_to_pdu(rq);
+ u32 host_cap_64 = readl(dd->mmio + HOST_CAP) & HOST_CAP_64;

/*
* For flush requests, request_idx starts at the end of the
@@ -3889,6 +3866,17 @@ static int mtip_init_cmd(void *data, str

memset(cmd->command, 0, CMD_DMA_ALLOC_SZ);

+ /* Point the command headers at the command tables. */
+ cmd->command_header = dd->port->command_list +
+ (sizeof(struct mtip_cmd_hdr) * request_idx);
+ cmd->command_header_dma = dd->port->command_list_dma +
+ (sizeof(struct mtip_cmd_hdr) * request_idx);
+
+ if (host_cap_64)
+ cmd->command_header->ctbau = __force_bit2int cpu_to_le32((cmd->command_dma >> 16) >> 16);
+
+ cmd->command_header->ctba = __force_bit2int cpu_to_le32(cmd->command_dma & 0xFFFFFFFF);
+
sg_init_table(cmd->sg, MTIP_MAX_SG);
return 0;
}