8:36 a.m.
nd_cmd_out_size is called by __nd_ioctl to size the buffer passed to
acpi_nfit_ctl. If the DSM function being called has a variable
sized output, nd_cmd_out_size will look at the return field to
determine buffer size. However, the DSM call hasn't been made yet,
so output size is core residue.
Have nd_cmd_out_size be bimodal with version "early" to be called
before the DSM call is made. For variable sized output fields
have it return ND_IOCTL_MAX_BUFLEN. __nd_ioctl sees new return
values and adjust buffer size accordingly.
The downside to this approach are:
1) Requires user buffer input size to be ND_IOCTL_MAX_BUFLEN (4 MB) for
calls to DSM with variable return.
2) The needless copyin of 4MB
An alternative approach (not yet prototyped) would move the call
to nd_cmd_out_size until after the return from acpi_nfit_ctl. Here,
the call has been made and return size would be known.
The size of the buffer allocated in would always be ND_IOCTL_MAX_BUFLEN.
Signed-off-by: Jerry Hoemann <jerry.hoemann(a)hpe.com>
---
drivers/nvdimm/bus.c | 30 ++++++++++++++++++++++++------
1 file changed, 24 insertions(+), 6 deletions(-)
diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index 23d4a17..50f8cc6 100644
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -713,9 +713,9 @@ u32 nd_cmd_in_size(struct nvdimm *nvdimm, int cmd,
}
EXPORT_SYMBOL_GPL(nd_cmd_in_size);
-u32 nd_cmd_out_size(struct nvdimm *nvdimm, int cmd,
+u32 nd_cmd_out_size_early(struct nvdimm *nvdimm, int cmd,
const struct nd_cmd_desc *desc, int idx, const u32 *in_field,
- const u32 *out_field, unsigned long remainder)
+ const u32 *out_field, unsigned long remainder, int early)
{
if (idx >= desc->out_num)
return UINT_MAX;
@@ -725,9 +725,13 @@ u32 nd_cmd_out_size(struct nvdimm *nvdimm, int cmd,
if (nvdimm && cmd == ND_CMD_GET_CONFIG_DATA && idx == 1)
return in_field[1];
- else if (nvdimm && cmd == ND_CMD_VENDOR && idx == 2)
+ else if (nvdimm && cmd == ND_CMD_VENDOR && idx == 2) {
+ if (early)
+ return ND_IOCTL_MAX_BUFLEN;
return out_field[1];
- else if (!nvdimm && cmd == ND_CMD_ARS_STATUS && idx == 2) {
+ } else if (!nvdimm && cmd == ND_CMD_ARS_STATUS && idx == 2) {
+ if (early)
+ return ND_IOCTL_MAX_BUFLEN;
/*
* Per table 9-276 ARS Data in ACPI 6.1, out_field[1] is
* "Size of Output Buffer in bytes, including this
@@ -753,6 +757,13 @@ u32 nd_cmd_out_size(struct nvdimm *nvdimm, int cmd,
return UINT_MAX;
}
+
+u32 nd_cmd_out_size(struct nvdimm *nvdimm, int cmd,
+ const struct nd_cmd_desc *desc, int idx, const u32 *in_field,
+ const u32 *out_field, unsigned long remainder)
+{
+ return nd_cmd_out_size_early(nvdimm, cmd, desc, idx, in_field, out_field, remainder,
0);
+}
EXPORT_SYMBOL_GPL(nd_cmd_out_size);
void wait_nvdimm_bus_probe_idle(struct device *dev)
@@ -890,10 +901,17 @@ static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm
*nvdimm,
/* process an output envelope */
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);
+ u32 out_size = nd_cmd_out_size_early(nvdimm, cmd, desc, i,
+ (u32 *) in_env, (u32 *) out_env, 0, 1);
u32 copy;
+ if (out_size == ND_IOCTL_MAX_BUFLEN) {
+ /* variable sized output */
+ out_len = out_size;
+ out_len -= in_len;
+ break;
+ }
+
if (out_size == UINT_MAX) {
dev_dbg(dev, "%s:%s unknown output size cmd: %s field: %d\n",
__func__, dimm_name, cmd_name, i);
--
1.8.3.1