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

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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>
This commit is contained in:
Dan Williams 2019-07-17 18:08:09 -07:00
parent 700cd033a8
commit 6de5d06e65
1 changed files with 37 additions and 22 deletions
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55
drivers/nvdimm/bus.c
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@ -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;
}