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| author | Caleb Sander Mateos <csander@purestorage.com> | 2025-06-20 09:10:03 -0600 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2025-06-30 20:13:42 -0600 |
| commit | 763ff02ce287c2e5c8a012d40bd2f3dab99ae5d5 (patch) | |
| tree | 3b8fe03b14f24060613990073768c4ebd4508fd1 /include | |
| parent | ublk: don't take ublk_queue in ublk_unregister_io_buf() (diff) | |
| download | linux-763ff02ce287c2e5c8a012d40bd2f3dab99ae5d5.tar.gz linux-763ff02ce287c2e5c8a012d40bd2f3dab99ae5d5.zip | |
ublk: allow UBLK_IO_(UN)REGISTER_IO_BUF on any task
Currently, UBLK_IO_REGISTER_IO_BUF and UBLK_IO_UNREGISTER_IO_BUF are
only permitted on the ublk_io's daemon task. But this restriction is
unnecessary. ublk_register_io_buf() calls __ublk_check_and_get_req() to
look up the request from the tagset and atomically take a reference on
the request without accessing the ublk_io. ublk_unregister_io_buf()
doesn't use the q_id or tag at all.
So allow these opcodes even on tasks other than io->task.
Handle UBLK_IO_UNREGISTER_IO_BUF before obtaining the ubq and io since
the buffer index being unregistered is not necessarily related to the
specified q_id and tag.
Add a feature flag UBLK_F_BUF_REG_OFF_DAEMON that userspace can use to
determine whether the kernel supports off-daemon buffer registration.
Suggested-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250620151008.3976463-10-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include')
| -rw-r--r-- | include/uapi/linux/ublk_cmd.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h index c9751bdfd937..ec77dabba45b 100644 --- a/include/uapi/linux/ublk_cmd.h +++ b/include/uapi/linux/ublk_cmd.h @@ -301,6 +301,16 @@ */ #define UBLK_F_PER_IO_DAEMON (1ULL << 13) +/* + * If this feature is set, UBLK_U_IO_REGISTER_IO_BUF/UBLK_U_IO_UNREGISTER_IO_BUF + * can be issued for an I/O on any task. q_id and tag are also ignored in + * UBLK_U_IO_UNREGISTER_IO_BUF's ublksrv_io_cmd. + * If it is unset, zero-copy buffers can only be registered and unregistered by + * the I/O's daemon task. The q_id and tag of the registered buffer are required + * in UBLK_U_IO_UNREGISTER_IO_BUF's ublksrv_io_cmd. + */ +#define UBLK_F_BUF_REG_OFF_DAEMON (1ULL << 14) + /* device state */ #define UBLK_S_DEV_DEAD 0 #define UBLK_S_DEV_LIVE 1 |