Changes since v3 [1]:
- Drop cxl_memdev_activate(). An open-coded pointer assignment is
sufficient relative to cdev_device_add() publishing the device (Jason)
[1]: http://lore.kernel.org/r/161714738634.2168142.10860201861152789544.stgit@dwillia2-desk3.amr.corp.intel.com
---
A collection of fixes initially inspired by Jason's recognition of
dev_set_name() error handling mistakes on other driver review, but also
from a deeper discussion of idiomatic device operation shutdown flows.
The end result is easier to reason about and validate. Thank you, Jason.
The sysfs_emit() fixup and unpublishing of device power management files
are independent sanity cleanups.
---
Dan Williams (4):
cxl/mem: Use sysfs_emit() for attribute show routines
cxl/mem: Fix synchronization mechanism for device removal vs ioctl operations
cxl/mem: Do not rely on device_add() side effects for dev_set_name() failures
cxl/mem: Disable cxl device power management
drivers/cxl/mem.c | 141 +++++++++++++++++++++++++++++++----------------------
1 file changed, 82 insertions(+), 59 deletions(-)
base-commit: a38fd8748464831584a19438cbb3082b5a2dab15
While none the CXL sysfs attributes are threatening to overrun a
PAGE_SIZE of output, it is good form to use the recommended helpers.
Fixes: b39cb1052a5c ("cxl/mem: Register CXL memX devices")
Reported-by: Jason Gunthorpe <[email protected]>
Reviewed-by: Ben Widawsky <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]>
Signed-off-by: Dan Williams <[email protected]>
---
drivers/cxl/mem.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index ecfc9ccdba8d..30bf4f0f3c17 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -1066,7 +1066,7 @@ static ssize_t firmware_version_show(struct device *dev,
struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
struct cxl_mem *cxlm = cxlmd->cxlm;
- return sprintf(buf, "%.16s\n", cxlm->firmware_version);
+ return sysfs_emit(buf, "%.16s\n", cxlm->firmware_version);
}
static DEVICE_ATTR_RO(firmware_version);
@@ -1076,7 +1076,7 @@ static ssize_t payload_max_show(struct device *dev,
struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
struct cxl_mem *cxlm = cxlmd->cxlm;
- return sprintf(buf, "%zu\n", cxlm->payload_size);
+ return sysfs_emit(buf, "%zu\n", cxlm->payload_size);
}
static DEVICE_ATTR_RO(payload_max);
@@ -1087,7 +1087,7 @@ static ssize_t ram_size_show(struct device *dev, struct device_attribute *attr,
struct cxl_mem *cxlm = cxlmd->cxlm;
unsigned long long len = range_len(&cxlm->ram_range);
- return sprintf(buf, "%#llx\n", len);
+ return sysfs_emit(buf, "%#llx\n", len);
}
static struct device_attribute dev_attr_ram_size =
@@ -1100,7 +1100,7 @@ static ssize_t pmem_size_show(struct device *dev, struct device_attribute *attr,
struct cxl_mem *cxlm = cxlmd->cxlm;
unsigned long long len = range_len(&cxlm->pmem_range);
- return sprintf(buf, "%#llx\n", len);
+ return sysfs_emit(buf, "%#llx\n", len);
}
static struct device_attribute dev_attr_pmem_size =
While device_add() will happen to catch dev_set_name() failures it is a
broken pattern to follow given that the core may try to fall back to a
different name.
Add explicit checking for dev_set_name() failures to be cleaned up by
put_device(). Skip cdev_device_add() and proceed directly to
put_device() if the name set fails.
This type of bug is easier to see if 'alloc' is split from 'add'
operations that require put_device() on failure. So cxl_memdev_alloc()
is split out as a result.
Fixes: b39cb1052a5c ("cxl/mem: Register CXL memX devices")
Reported-by: Jason Gunthorpe <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]>
Signed-off-by: Dan Williams <[email protected]>
---
drivers/cxl/mem.c | 39 +++++++++++++++++++++++++++++----------
1 file changed, 29 insertions(+), 10 deletions(-)
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index c77d375fad95..e59b373694d3 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -1180,7 +1180,7 @@ static void cxl_memdev_unregister(void *_cxlmd)
put_device(dev);
}
-static int cxl_mem_add_memdev(struct cxl_mem *cxlm)
+static struct cxl_memdev *cxl_memdev_alloc(struct cxl_mem *cxlm)
{
struct pci_dev *pdev = cxlm->pdev;
struct cxl_memdev *cxlmd;
@@ -1190,11 +1190,11 @@ static int cxl_mem_add_memdev(struct cxl_mem *cxlm)
cxlmd = kzalloc(sizeof(*cxlmd), GFP_KERNEL);
if (!cxlmd)
- return -ENOMEM;
+ return ERR_PTR(-ENOMEM);
rc = ida_alloc_range(&cxl_memdev_ida, 0, CXL_MEM_MAX_DEVS, GFP_KERNEL);
if (rc < 0)
- goto err_id;
+ goto err;
cxlmd->id = rc;
dev = &cxlmd->dev;
@@ -1203,10 +1203,31 @@ static int cxl_mem_add_memdev(struct cxl_mem *cxlm)
dev->bus = &cxl_bus_type;
dev->devt = MKDEV(cxl_mem_major, cxlmd->id);
dev->type = &cxl_memdev_type;
- dev_set_name(dev, "mem%d", cxlmd->id);
cdev = &cxlmd->cdev;
cdev_init(cdev, &cxl_memdev_fops);
+ return cxlmd;
+
+err:
+ kfree(cxlmd);
+ return ERR_PTR(rc);
+}
+
+static int cxl_mem_add_memdev(struct cxl_mem *cxlm)
+{
+ struct cxl_memdev *cxlmd;
+ struct device *dev;
+ struct cdev *cdev;
+ int rc;
+
+ cxlmd = cxl_memdev_alloc(cxlm);
+ if (IS_ERR(cxlmd))
+ return PTR_ERR(cxlmd);
+
+ dev = &cxlmd->dev;
+ rc = dev_set_name(dev, "mem%d", cxlmd->id);
+ if (rc)
+ goto err;
/*
* Activate ioctl operations, no cxl_memdev_rwsem manipulation
@@ -1214,23 +1235,21 @@ static int cxl_mem_add_memdev(struct cxl_mem *cxlm)
*/
cxlmd->cxlm = cxlm;
+ cdev = &cxlmd->cdev;
rc = cdev_device_add(cdev, dev);
if (rc)
- goto err_add;
+ goto err;
return devm_add_action_or_reset(dev->parent, cxl_memdev_unregister,
cxlmd);
-err_add:
+err:
/*
* The cdev was briefly live, shutdown any ioctl operations that
* saw that state.
*/
cxl_memdev_shutdown(cxlmd);
- ida_free(&cxl_memdev_ida, cxlmd->id);
-err_id:
- kfree(cxlmd);
-
+ put_device(dev);
return rc;
}