From 6e0ae74b5ca2826fa6c86a157ed5227c766156b9 Mon Sep 17 00:00:00 2001 From: Narsimhulu Musini Date: Thu, 17 Mar 2016 00:51:12 -0700 Subject: [PATCH] snic: Handling control path queue issues Fix handles control path queue issues such as queue full and sudden removal of hardware. Signed-off-by: Narsimhulu Musini Signed-off-by: Sesidhar Baddela Signed-off-by: Martin K. Petersen --- drivers/scsi/snic/vnic_dev.c | 44 ++++++++++++++++++++++++++++++-------------- 1 file changed, 30 insertions(+), 14 deletions(-) diff --git a/drivers/scsi/snic/vnic_dev.c b/drivers/scsi/snic/vnic_dev.c index e0b5549bc9fb..dad5fc66effb 100644 --- a/drivers/scsi/snic/vnic_dev.c +++ b/drivers/scsi/snic/vnic_dev.c @@ -263,12 +263,20 @@ static int _svnic_dev_cmd2(struct vnic_dev *vdev, enum vnic_devcmd_cmd cmd, int wait) { struct devcmd2_controller *dc2c = vdev->devcmd2; - struct devcmd2_result *result = dc2c->result + dc2c->next_result; + struct devcmd2_result *result = NULL; unsigned int i; int delay; int err; u32 posted; + u32 fetch_idx; u32 new_posted; + u8 color; + + fetch_idx = ioread32(&dc2c->wq_ctrl->fetch_index); + if (fetch_idx == 0xFFFFFFFF) { /* check for hardware gone */ + /* Hardware surprise removal: return error */ + return -ENODEV; + } posted = ioread32(&dc2c->wq_ctrl->posted_index); @@ -278,6 +286,13 @@ static int _svnic_dev_cmd2(struct vnic_dev *vdev, enum vnic_devcmd_cmd cmd, } new_posted = (posted + 1) % DEVCMD2_RING_SIZE; + if (new_posted == fetch_idx) { + pr_err("%s: wq is full while issuing devcmd2 command %d, fetch index: %u, posted index: %u\n", + pci_name(vdev->pdev), _CMD_N(cmd), fetch_idx, posted); + + return -EBUSY; + } + dc2c->cmd_ring[posted].cmd = cmd; dc2c->cmd_ring[posted].flags = 0; @@ -299,14 +314,22 @@ static int _svnic_dev_cmd2(struct vnic_dev *vdev, enum vnic_devcmd_cmd cmd, if (dc2c->cmd_ring[posted].flags & DEVCMD2_FNORESULT) return 0; + result = dc2c->result + dc2c->next_result; + color = dc2c->color; + + /* + * Increment next_result, after posting the devcmd, irrespective of + * devcmd result, and it should be done only once. + */ + dc2c->next_result++; + if (dc2c->next_result == dc2c->result_size) { + dc2c->next_result = 0; + dc2c->color = dc2c->color ? 0 : 1; + } + for (delay = 0; delay < wait; delay++) { udelay(100); - if (result->color == dc2c->color) { - dc2c->next_result++; - if (dc2c->next_result == dc2c->result_size) { - dc2c->next_result = 0; - dc2c->color = dc2c->color ? 0 : 1; - } + if (result->color == color) { if (result->error) { err = (int) result->error; if (err != ERR_ECMDUNKNOWN || @@ -317,13 +340,6 @@ static int _svnic_dev_cmd2(struct vnic_dev *vdev, enum vnic_devcmd_cmd cmd, return err; } if (_CMD_DIR(cmd) & _CMD_DIR_READ) { - /* - * Adding the rmb() prevents the compiler - * and/or CPU from reordering the reads which - * would potentially result in reading stale - * values. - */ - rmb(); for (i = 0; i < VNIC_DEVCMD_NARGS; i++) vdev->args[i] = result->results[i]; } -- 2.11.0