lkml.org 
[lkml]   [2019]   [Aug]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 5.2 02/56] libnvdimm/bus: Prepare the nd_ioctl() path to be re-entrant
Date
commit 6de5d06e657acdbcf9637dac37916a4a5309e0f4 upstream.

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: Vishal Verma <vishal.l.verma@intel.com>
Reviewed-by: Vishal Verma <vishal.l.verma@intel.com>
Tested-by: Vishal 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: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/nvdimm/bus.c | 59 +++++++++++++++++++++++++++-----------------
1 file changed, 37 insertions(+), 22 deletions(-)

diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index dfb93228d6a73..a38572bf486bb 100644
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -973,20 +973,19 @@ 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);
@@ -1026,6 +1025,9 @@ 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;

@@ -1033,14 +1035,17 @@ 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;
}

@@ -1052,6 +1057,12 @@ 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);
@@ -1060,15 +1071,18 @@ 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;
}

@@ -1076,12 +1090,15 @@ 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;
@@ -1103,17 +1120,15 @@ 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:
+out_unlock:
nvdimm_bus_unlock(&nvdimm_bus->dev);
- out:
+out:
+ kfree(in_env);
+ kfree(out_env);
vfree(buf);
return rc;
}
--
2.20.1


\
 
 \ /
  Last update: 2019-08-08 21:09    [W:0.334 / U:1.004 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site