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Commit 6de5d06e authored by Dan Williams's avatar Dan Williams
Browse files

libnvdimm/bus: Prepare the nd_ioctl() path to be re-entrant 



In preparation for not holding a lock over the execution of nd_ioctl(),
update the implementation to allow multiple threads to be attempting
ioctls at the same time. The bus lock still prevents multiple in-flight
->ndctl() invocations from corrupting each other's state, but static
global staging buffers are moved to the heap.

Reported-by: default avatarVishal Verma <vishal.l.verma@intel.com>
Reviewed-by: default avatarVishal Verma <vishal.l.verma@intel.com>
Tested-by: default avatarVishal Verma <vishal.l.verma@intel.com>
Link: https://lore.kernel.org/r/156341208947.292348.10560140326807607481.stgit@dwillia2-desk3.amr.corp.intel.com


Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 700cd033

drivers/nvdimm/bus.c

+37 −22
Original line number Diff line number Diff line
@@ -970,20 +970,19 @@ static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm, 
		int read_only, unsigned int ioctl_cmd, unsigned long arg)

{

	struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;

	static char out_env[ND_CMD_MAX_ENVELOPE];

	static char in_env[ND_CMD_MAX_ENVELOPE];

	const struct nd_cmd_desc *desc = NULL;

	unsigned int cmd = _IOC_NR(ioctl_cmd);

	struct device *dev = &nvdimm_bus->dev;

	void __user *p = (void __user *) arg;

	char *out_env = NULL, *in_env = NULL;

	const char *cmd_name, *dimm_name;

	u32 in_len = 0, out_len = 0;

	unsigned int func = cmd;

	unsigned long cmd_mask;

	struct nd_cmd_pkg pkg;

	int rc, i, cmd_rc;

	void *buf = NULL;

	u64 buf_len = 0;

	void *buf;



	if (nvdimm) {

		desc = nd_cmd_dimm_desc(cmd);
@@ -1023,6 +1022,9 @@ static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm, 
		}



	/* process an input envelope */

	in_env = kzalloc(ND_CMD_MAX_ENVELOPE, GFP_KERNEL);

	if (!in_env)

		return -ENOMEM;

	for (i = 0; i < desc->in_num; i++) {

		u32 in_size, copy;
@@ -1030,14 +1032,17 @@ static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm, 
		if (in_size == UINT_MAX) {

			dev_err(dev, "%s:%s unknown input size cmd: %s field: %d\n",

					__func__, dimm_name, cmd_name, i);

			return -ENXIO;

			rc = -ENXIO;

			goto out;

		}

		if (in_len < sizeof(in_env))

			copy = min_t(u32, sizeof(in_env) - in_len, in_size);

		if (in_len < ND_CMD_MAX_ENVELOPE)

			copy = min_t(u32, ND_CMD_MAX_ENVELOPE - in_len, in_size);

		else

			copy = 0;

		if (copy && copy_from_user(&in_env[in_len], p + in_len, copy))

			return -EFAULT;

		if (copy && copy_from_user(&in_env[in_len], p + in_len, copy)) {

			rc = -EFAULT;

			goto out;

		}

		in_len += in_size;

	}
@@ -1049,6 +1054,12 @@ static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm, 
	}



	/* process an output envelope */

	out_env = kzalloc(ND_CMD_MAX_ENVELOPE, GFP_KERNEL);

	if (!out_env) {

		rc = -ENOMEM;

		goto out;

	}



	for (i = 0; i < desc->out_num; i++) {

		u32 out_size = nd_cmd_out_size(nvdimm, cmd, desc, i,

				(u32 *) in_env, (u32 *) out_env, 0);
@@ -1057,15 +1068,18 @@ static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm, 
		if (out_size == UINT_MAX) {

			dev_dbg(dev, "%s unknown output size cmd: %s field: %d\n",

					dimm_name, cmd_name, i);

			return -EFAULT;

			rc = -EFAULT;

			goto out;

		}

		if (out_len < sizeof(out_env))

			copy = min_t(u32, sizeof(out_env) - out_len, out_size);

		if (out_len < ND_CMD_MAX_ENVELOPE)

			copy = min_t(u32, ND_CMD_MAX_ENVELOPE - out_len, out_size);

		else

			copy = 0;

		if (copy && copy_from_user(&out_env[out_len],

					p + in_len + out_len, copy))

			return -EFAULT;

					p + in_len + out_len, copy)) {

			rc = -EFAULT;

			goto out;

		}

		out_len += out_size;

	}
@@ -1073,12 +1087,15 @@ static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm, 
	if (buf_len > ND_IOCTL_MAX_BUFLEN) {

		dev_dbg(dev, "%s cmd: %s buf_len: %llu > %d\n", dimm_name,

				cmd_name, buf_len, ND_IOCTL_MAX_BUFLEN);

		return -EINVAL;

		rc = -EINVAL;

		goto out;

	}



	buf = vmalloc(buf_len);

	if (!buf)

		return -ENOMEM;

	if (!buf) {

		rc = -ENOMEM;

		goto out;

	}



	if (copy_from_user(buf, p, buf_len)) {

		rc = -EFAULT;
@@ -1100,17 +1117,15 @@ static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm, 
		nvdimm_account_cleared_poison(nvdimm_bus, clear_err->address,

				clear_err->cleared);

	}

	nvdimm_bus_unlock(&nvdimm_bus->dev);



	if (copy_to_user(p, buf, buf_len))

		rc = -EFAULT;



	vfree(buf);

	return rc;



out_unlock:

	nvdimm_bus_unlock(&nvdimm_bus->dev);

out:

	kfree(in_env);

	kfree(out_env);

	vfree(buf);

	return rc;

}