[PATCH] Don't change direction flags in struct request.
in [Kernel]
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From: Hugh Daschbach on 1 Mar 2010 19:10 The EMC multipath device handler should not change the I/O direction flags of its trespass command request. The CFQ elevator may BUG if the direction flags on an I/O request are changed after allocation. cfq_set_request() and cfq_put_request() count READ and WRITE requests separately. Changing the I/O request direction after blk_get_request() allocates the request throws off this CFQ accounting. Signed-off-by: Hugh Daschbach <hdasch(a)broadcom.com> --- drivers/scsi/device_handler/scsi_dh_emc.c | 8 ++++---- 1 files changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/scsi/device_handler/scsi_dh_emc.c b/drivers/scsi/device_handler/scsi_dh_emc.c index 6196675..3709342 100644 --- a/drivers/scsi/device_handler/scsi_dh_emc.c +++ b/drivers/scsi/device_handler/scsi_dh_emc.c @@ -269,10 +269,12 @@ static struct request *get_req(struct scsi_device *sdev, int cmd, unsigned char *buffer) { struct request *rq; + int mode = READ; int len = 0; - rq = blk_get_request(sdev->request_queue, - (cmd == MODE_SELECT) ? WRITE : READ, GFP_NOIO); + if (cmd == MODE_SELECT || cmd == MODE_SELECT_10) + mode = WRITE; + rq = blk_get_request(sdev->request_queue, mode, GFP_NOIO); if (!rq) { sdev_printk(KERN_INFO, sdev, "get_req: blk_get_request failed"); return NULL; @@ -284,12 +286,10 @@ static struct request *get_req(struct scsi_device *sdev, int cmd, switch (cmd) { case MODE_SELECT: len = sizeof(short_trespass); - rq->cmd_flags |= REQ_RW; rq->cmd[1] = 0x10; break; case MODE_SELECT_10: len = sizeof(long_trespass); - rq->cmd_flags |= REQ_RW; rq->cmd[1] = 0x10; break; case INQUIRY: -- 1.6.6.196.g1f735 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |