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cxl/uapi: Tag commands from cxl_query_cmd()

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It was pointed out that commands not supported by the device or excluded
by the kernel were being returned in cxl_query_cmd().[1]

While libcxl correctly handles failing commands, it is more efficient to
not issue an invalid command in the first place.  This can't be done
without additional information being returned from cxl_query_cmd().  In
addition, information about the availability of commands can be useful
for debugging.

Add flags to struct cxl_command_info which reflect if a command is
enabled and/or exclusive to the kernel.

[1] https://lore.kernel.org/all/63b4ec4e37cc1_5178e2941d@dwillia2-xfh.jf.intel.com.notmuch/

Suggested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20221222-cxl-misc-v4-3-62f701c1cdd1@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Ira Weiny 2023-02-02 17:04:26 -08:00 committed by Dan Williams
parent 11ef026e46
commit 814a15f3b4
2 changed files with 24 additions and 4 deletions
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9
drivers/cxl/core/mbox.c
View File

@ -451,9 +451,14 @@ int cxl_query_cmd(struct cxl_memdev *cxlmd,
* structures.
*/
cxl_for_each_cmd(cmd) {
const struct cxl_command_info *info = &cmd->info;
struct cxl_command_info info = cmd->info;
if (copy_to_user(&q->commands[j++], info, sizeof(*info)))
if (test_bit(info.id, cxlmd->cxlds->enabled_cmds))
info.flags |= CXL_MEM_COMMAND_FLAG_ENABLED;
if (test_bit(info.id, cxlmd->cxlds->exclusive_cmds))
info.flags |= CXL_MEM_COMMAND_FLAG_EXCLUSIVE;
if (copy_to_user(&q->commands[j++], &info, sizeof(info)))
return -EFAULT;
if (j == n_commands)

19
include/uapi/linux/cxl_mem.h
View File

@ -72,6 +72,19 @@ static const struct {
* struct cxl_command_info - Command information returned from a query.
* @id: ID number for the command.
* @flags: Flags that specify command behavior.
*
* CXL_MEM_COMMAND_FLAG_USER_ENABLED
*
* The given command id is supported by the driver and is supported by
* a related opcode on the device.
*
* CXL_MEM_COMMAND_FLAG_EXCLUSIVE
*
* Requests with the given command id will terminate with EBUSY as the
* kernel actively owns management of the given resource. For example,
* the label-storage-area can not be written while the kernel is
* actively managing that space.
*
* @size_in: Expected input size, or ~0 if variable length.
* @size_out: Expected output size, or ~0 if variable length.
*
@ -81,7 +94,7 @@ static const struct {
* bytes of output.
*
* - @id = 10
* - @flags = 0
* - @flags = CXL_MEM_COMMAND_FLAG_ENABLED
* - @size_in = ~0
* - @size_out = 0
*
@ -91,7 +104,9 @@ struct cxl_command_info {
__u32 id;
__u32 flags;
#define CXL_MEM_COMMAND_FLAG_MASK GENMASK(0, 0)
#define CXL_MEM_COMMAND_FLAG_MASK GENMASK(1, 0)
#define CXL_MEM_COMMAND_FLAG_ENABLED BIT(0)
#define CXL_MEM_COMMAND_FLAG_EXCLUSIVE BIT(1)
__u32 size_in;
__u32 size_out;