cxlflash: Reorder user context initialization

In order to support cxlflash in the PowerVM environment, underlying
hypervisor APIs have imposed a kernel API ordering change.

For the superpipe access to LUN, user applications need a context.
The cxlflash module creates this context by making a sequence of
cxl calls. In the current code, a context is initialized via
cxl_dev_context_init() followed by cxl_process_element(), a function
that obtains the process element id. Finally, cxl_start_work()
is called to attach the process element.

In the PowerVM environment, a process element id cannot be obtained
from the hypervisor until the process element is attached. The
cxlflash module is unable to create contexts without a valid
process element id.

To fix this problem, cxl_start_work() is called before obtaining
the process element id.

Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Acked-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 28 insertions, 28 deletions

diff --git a/drivers/scsi/cxlflash/superpipe.c b/drivers/scsi/cxlflash/superpipe.c
index 7ec0b7a92876..d8a5cb3cd2bd 100644
--- a/drivers/scsi/cxlflash/superpipe.c
+++ b/drivers/scsi/cxlflash/superpipe.c
@@ -1386,6 +1386,13 @@ static int cxlflash_disk_attach(struct scsi_device *sdev,
                 goto out_attach;
         }
 
+        ctxi = create_context(cfg);
+        if (unlikely(!ctxi)) {
+                dev_err(dev, "%s: Failed to create context! (%d)\n",
+                        __func__, ctxid);
+                goto err;
+        }
+
         ctx = cxl_dev_context_init(cfg->dev);
         if (IS_ERR_OR_NULL(ctx)) {
                 dev_err(dev, "%s: Could not initialize context %p\n",
@@ -1394,6 +1401,17 @@ static int cxlflash_disk_attach(struct scsi_device *sdev,
                 goto err;
         }
 
+        work = &ctxi->work;
+        work->num_interrupts = attach->num_interrupts;
+        work->flags = CXL_START_WORK_NUM_IRQS;
+
+        rc = cxl_start_work(ctx, work);
+        if (unlikely(rc)) {
+                dev_dbg(dev, "%s: Could not start context rc=%d\n",
+                        __func__, rc);
+                goto err;
+        }
+
         ctxid = cxl_process_element(ctx);
         if (unlikely((ctxid >= MAX_CONTEXT) || (ctxid < 0))) {
                 dev_err(dev, "%s: ctxid (%d) invalid!\n", __func__, ctxid);
@@ -1411,27 +1429,9 @@ static int cxlflash_disk_attach(struct scsi_device *sdev,
         /* Translate read/write O_* flags from fcntl.h to AFU permission bits */
         perms = SISL_RHT_PERM(attach->hdr.flags + 1);
 
-        ctxi = create_context(cfg);
-        if (unlikely(!ctxi)) {
-                dev_err(dev, "%s: Failed to create context! (%d)\n",
-                        __func__, ctxid);
-                goto err;
-        }
-
         /* Context mutex is locked upon return */
         init_context(ctxi, cfg, ctx, ctxid, fd, file, perms);
 
-        work = &ctxi->work;
-        work->num_interrupts = attach->num_interrupts;
-        work->flags = CXL_START_WORK_NUM_IRQS;
-
-        rc = cxl_start_work(ctx, work);
-        if (unlikely(rc)) {
-                dev_dbg(dev, "%s: Could not start context rc=%d\n",
-                        __func__, rc);
-                goto err;
-        }
-
         rc = afu_attach(cfg, ctxi);
         if (unlikely(rc)) {
                 dev_err(dev, "%s: Could not attach AFU rc %d\n", __func__, rc);
@@ -1532,24 +1532,24 @@ static int recover_context(struct cxlflash_cfg *cfg, struct ctx_info *ctxi)
                 goto out;
         }
 
+        rc = cxl_start_work(ctx, &ctxi->work);
+        if (unlikely(rc)) {
+                dev_dbg(dev, "%s: Could not start context rc=%d\n",
+                        __func__, rc);
+                goto err1;
+        }
+
         ctxid = cxl_process_element(ctx);
         if (unlikely((ctxid >= MAX_CONTEXT) || (ctxid < 0))) {
                 dev_err(dev, "%s: ctxid (%d) invalid!\n", __func__, ctxid);
                 rc = -EPERM;
-                goto err1;
+                goto err2;
         }
 
         file = cxl_get_fd(ctx, &cfg->cxl_fops, &fd);
         if (unlikely(fd < 0)) {
                 rc = -ENODEV;
                 dev_err(dev, "%s: Could not get file descriptor\n", __func__);
-                goto err1;
-        }
-
-        rc = cxl_start_work(ctx, &ctxi->work);
-        if (unlikely(rc)) {
-                dev_dbg(dev, "%s: Could not start context rc=%d\n",
-                        __func__, rc);
                 goto err2;
         }
 
@@ -1594,10 +1594,10 @@ out:
         return rc;
 
 err3:
-        cxl_stop_context(ctx);
-err2:
         fput(file);
         put_unused_fd(fd);
+err2:
+        cxl_stop_context(ctx);
 err1:
         cxl_release_context(ctx);
         goto out;