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cxlflash: Fix potential oops following LUN removal 

When a LUN is removed, the sdev that is associated with the LUN
remains intact until its reference count drops to 0. In order
to prevent an sdev from being removed while a context is still
associated with it, obtain an additional reference per-context
for each LUN attached to the context.

This resolves a potential Oops in the release handler when a
dealing with a LUN that has already been removed.

Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>
Reviewed-by: Brian King <brking@linux.vnet.ibm.com>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
This commit is contained in:
Matthew R. Ochs 2015-10-21 15:11:18 -05:00 committed by James Bottomley
parent 471a5a60aa
commit 22fe1ae80f
1 changed files with 23 additions and 12 deletions
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35
drivers/scsi/cxlflash/superpipe.c
View File

@ -880,6 +880,9 @@ static int _cxlflash_disk_detach(struct scsi_device *sdev,
sys_close(lfd);
}
/* Release the sdev reference that bound this LUN to the context */
scsi_device_put(sdev);
out:
if (put_ctx)
put_context(ctxi);
@ -1287,11 +1290,17 @@ static int cxlflash_disk_attach(struct scsi_device *sdev,
}
}
rc = scsi_device_get(sdev);
if (unlikely(rc)) {
dev_err(dev, "%s: Unable to get sdev reference!\n", __func__);
goto out;
}
lun_access = kzalloc(sizeof(*lun_access), GFP_KERNEL);
if (unlikely(!lun_access)) {
dev_err(dev, "%s: Unable to allocate lun_access!\n", __func__);
rc = -ENOMEM;
goto out;
goto err0;
}
lun_access->lli = lli;
@ -1311,21 +1320,21 @@ static int cxlflash_disk_attach(struct scsi_device *sdev,
dev_err(dev, "%s: Could not initialize context %p\n",
__func__, ctx);
rc = -ENODEV;
goto err0;
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;
goto err2;
}
/* Translate read/write O_* flags from fcntl.h to AFU permission bits */
@ -1335,7 +1344,7 @@ static int cxlflash_disk_attach(struct scsi_device *sdev,
if (unlikely(!ctxi)) {
dev_err(dev, "%s: Failed to create context! (%d)\n",
__func__, ctxid);
goto err2;
goto err3;
}
work = &ctxi->work;
@ -1346,13 +1355,13 @@ static int cxlflash_disk_attach(struct scsi_device *sdev,
if (unlikely(rc)) {
dev_dbg(dev, "%s: Could not start context rc=%d\n",
__func__, rc);
goto err3;
goto err4;
}
rc = afu_attach(cfg, ctxi);
if (unlikely(rc)) {
dev_err(dev, "%s: Could not attach AFU rc %d\n", __func__, rc);
goto err4;
goto err5;
}
/*
@ -1388,13 +1397,13 @@ out:
__func__, ctxid, fd, attach->block_size, rc, attach->last_lba);
return rc;
err4:
err5:
cxl_stop_context(ctx);
err3:
err4:
put_context(ctxi);
destroy_context(cfg, ctxi);
ctxi = NULL;
err2:
err3:
/*
* Here, we're overriding the fops with a dummy all-NULL fops because
* fput() calls the release fop, which will cause us to mistakenly
@ -1406,10 +1415,12 @@ err2:
fput(file);
put_unused_fd(fd);
fd = -1;
err1:
err2:
cxl_release_context(ctx);
err0:
err1:
kfree(lun_access);
err0:
scsi_device_put(sdev);
goto out;
}