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authorNarsimhulu Musini <nmusini@cisco.com>2016-03-17 08:51:12 +0100
committerMartin K. Petersen <martin.petersen@oracle.com>2016-04-11 22:57:09 +0200
commit6e0ae74b5ca2826fa6c86a157ed5227c766156b9 (patch)
tree83fc00686403367a3d6d496609e3eadbe70774df /drivers/scsi/snic/vnic_dev.c
parentsnic: LUN goes offline due to scsi cmd timeouts (diff)
downloadlinux-6e0ae74b5ca2826fa6c86a157ed5227c766156b9.tar.xz
linux-6e0ae74b5ca2826fa6c86a157ed5227c766156b9.zip
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 <nmusini@cisco.com> Signed-off-by: Sesidhar Baddela <sebaddel@cisco.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/snic/vnic_dev.c')
-rw-r--r--drivers/scsi/snic/vnic_dev.c44
1 files 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];
}