kernel/linux.git/include/uapi/linux/target_core_user.h, branch v6.6.132

scsi: target: uapi: Replace fake flex-array with flexible-array member

2023-03-24T20:59:09+00:00

Zero-length arrays as fake flexible arrays are deprecated and we are moving towards adopting C99 flexible-array members instead. Address the following warning found with GCC-13 and -fstrict-flex-arrays=3 enabled: CC drivers/target/target_core_user.o drivers/target/target_core_user.c: In function ‘queue_cmd_ring’: drivers/target/target_core_user.c:1096:15: warning: array subscript 0 is outside array bounds of ‘struct iovec[0]’ [-Warray-bounds=] 1096 | iov = &entry->req.iov[0]; | ^~~~~~~~~~~~~~~~~~ In file included from drivers/target/target_core_user.c:31: ./include/uapi/linux/target_core_user.h:122:38: note: while referencing ‘iov’ 122 | struct iovec iov[0]; | ^~~ This helps with the ongoing efforts to tighten the FORTIFY_SOURCE routines on memcpy() and help us make progress towards globally enabling -fstrict-flex-arrays=3 [1]. Link: https://github.com/KSPP/linux/issues/21 Link: https://github.com/KSPP/linux/issues/270 Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1] Signed-off-by: Gustavo A. R. Silva Link: https://lore.kernel.org/r/ZBSchMvTdl7VObKI@work Reviewed-by: Bodo Stroesser Reviewed-by: Kees Cook Signed-off-by: Martin K. Petersen

treewide: uapi: Replace zero-length arrays with flexible-array members

2022-06-28T19:26:05+00:00

There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2]. This code was transformed with the help of Coccinelle: (linux-5.19-rc2$ spatch --jobs $(getconf _NPROCESSORS_ONLN) --sp-file script.cocci --include-headers --dir . > output.patch) @@ identifier S, member, array; type T1, T2; @@ struct S { ... T1 member; T2 array[ - 0 ]; }; -fstrict-flex-arrays=3 is coming and we need to land these changes to prevent issues like these in the short future: ../fs/minix/dir.c:337:3: warning: 'strcpy' will always overflow; destination buffer has size 0, but the source string has length 2 (including NUL byte) [-Wfortify-source] strcpy(de3->name, "."); ^ Since these are all [0] to [] changes, the risk to UAPI is nearly zero. If this breaks anything, we can use a union with a new member name. [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays Link: https://github.com/KSPP/linux/issues/78 Build-tested-by: kernel test robot Link: https://lore.kernel.org/lkml/62b675ec.wKX6AOZ6cbE71vtF%25lkp@intel.com/ Acked-by: Dan Williams # For ndctl.h Signed-off-by: Gustavo A. R. Silva

scsi: target: tcmu: Add new feature KEEP_BUF

2021-08-03T11:27:42+00:00

When running command pipelining for WRITE direction commands (e.g. tape device write), userspace sends cmd completion to cmd ring before processing write data. In that case userspace has to copy data before sending completion, because cmd completion also implicitly releases the data buffer in data area. The new feature KEEP_BUF allows userspace to optionally keep the buffer after completion by setting new bit TCMU_UFLAG_KEEP_BUF in tcmu_cmd_entry_hdr->uflags. In that case buffer has to be released explicitly by writing the cmd_id to new action item free_kept_buf. All kept buffers are released during reset_ring and if userspace closes uio device (tcmu_release). Link: https://lore.kernel.org/r/20210713175021.20103-1-bostroesser@gmail.com Reviewed-by: Mike Christie Signed-off-by: Bodo Stroesser Signed-off-by: Martin K. Petersen

scsi: target: tcmu: Implement tmr_notify callback

2020-07-29T02:25:30+00:00

This patch implements the tmr_notify callback for tcmu. When the callback is called, tcmu checks the list of aborted commands it received as parameter: - aborted commands in the qfull_queue are removed from the queue and target_complete_command is called - from the cmd_ids of aborted commands currently uncompleted in cmd ring it creates a list of aborted cmd_ids. Finally a TMR notification is written to cmd ring containing TMR type and cmd_id list. If there is no space in ring, the TMR notification is queued on a TMR specific queue. The TMR specific queue 'tmr_queue' can be seen as a extension of the cmd ring. At the end of each iexecution of tcmu_complete_commands() we check whether tmr_queue contains TMRs and try to move them onto the ring. If tmr_queue is not empty after that, we don't call run_qfull_queue() because commands must not overtake TMRs. This way we guarantee that cmd_ids in TMR notification received by userspace either match an active, not yet completed command or are no longer valid due to userspace having complete some cmd_ids meanwhile. New commands that were assigned to an aborted cmd_id will always appear on the cmd ring _after_ the TMR. Link: https://lore.kernel.org/r/20200726153510.13077-8-bstroesser@ts.fujitsu.com Reviewed-by: Mike Christie Signed-off-by: Bodo Stroesser Signed-off-by: Martin K. Petersen

scsi: target: tcmu: add read length support

2018-06-19T01:02:52+00:00

Generally target core and TCMUser seem to work fine for tape devices and media changers. But there is at least one situation where TCMUser is not able to support sequential access device emulation correctly. The situation is when an initiator sends a SCSI READ CDB with a length that is greater than the length of the tape block to read. We can distinguish two subcases: A) The initiator sent the READ CDB with the SILI bit being set. In this case the sequential access device has to transfer the data from the tape block (only the length of the tape block) and transmit a good status. The current interface between TCMUser and the userspace does not support reduction of the read data size by the userspace program. The patch below fixes this subcase by allowing the userspace program to specify a reduced data size in read direction. B) The initiator sent the READ CDB with the SILI bit not being set. In this case the sequential access device has to transfer the data from the tape block as in A), but additionally has to transmit CHECK CONDITION with the ILI bit set and NO SENSE in the sensebytes. The information field in the sensebytes must contain the residual count. With the below patch a user space program can specify the real read data length and appropriate sensebytes. TCMUser then uses the se_cmd flag SCF_TREAT_READ_AS_NORMAL, to force target core to transmit the real data size and the sensebytes. Note: the flag SCF_TREAT_READ_AS_NORMAL is introduced by Lee Duncan's patch "[PATCH v4] target: transport should handle st FM/EOM/ILI reads" from Tue, 15 May 2018 18:25:24 -0700. Signed-off-by: Bodo Stroesser Acked-by: Mike Christie Reviewed-by: Lee Duncan Signed-off-by: Martin K. Petersen

scsi: target: target_core_user.[ch]: convert comments into DOC:

2018-04-20T23:14:39+00:00

Make documentation on target-supported userspace-I/O design be usable by kernel-doc by using "DOC:". This is used in the driver-api Documentation chapter. Signed-off-by: Randy Dunlap To: "Nicholas A. Bellinger" Cc: linux-scsi@vger.kernel.org Cc: target-devel@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: "James E.J. Bottomley" Cc: "Martin K. Petersen" Cc: Jonathan Corbet Signed-off-by: Martin K. Petersen

License cleanup: add SPDX license identifier to uapi header files with no license

2017-11-02T10:19:54+00:00

Many user space API headers are missing licensing information, which makes it hard for compliance tools to determine the correct license. By default are files without license information under the default license of the kernel, which is GPLV2. Marking them GPLV2 would exclude them from being included in non GPLV2 code, which is obviously not intended. The user space API headers fall under the syscall exception which is in the kernels COPYING file: NOTE! This copyright does *not* cover user programs that use kernel services by normal system calls - this is merely considered normal use of the kernel, and does *not* fall under the heading of "derived work". otherwise syscall usage would not be possible. Update the files which contain no license information with an SPDX license identifier. The chosen identifier is 'GPL-2.0 WITH Linux-syscall-note' which is the officially assigned identifier for the Linux syscall exception. SPDX license identifiers are a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. See the previous patch in this series for the methodology of how this patch was researched. Reviewed-by: Kate Stewart Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

tcmu: perfom device add, del and reconfig synchronously

2017-07-07T06:11:39+00:00

This makes the device add, del reconfig operations sync. It fixes the issue where for add and reconfig, we do not know if userspace successfully completely the operation, so we leave invalid kernel structs or report incorrect status for the config/reconfig operations. Signed-off-by: Mike Christie Signed-off-by: Nicholas Bellinger

tcmu: reconfigure netlink attr changes

2017-07-07T06:11:36+00:00

1. TCMU_ATTR_TYPE is too generic when it describes only the reconfiguration type, so rename to TCMU_ATTR_RECONFIG_TYPE. 2. Only return the reconfig type when it is a TCMU_CMD_RECONFIG_DEVICE command. 3. CONFIG_* type is not needed. We can pass the value along with an ATTR to userspace, so it does not need to read sysfs/configfs. 4. Fix leak in tcmu_dev_path_store and rename to dev_config to reflect it is more than just a path that can be changed. 6. Don't update kernel struct value if netlink sending fails. Signed-off-by: Mike Christie Reviewed-by: "Bryant G. Ly" Signed-off-by: Nicholas Bellinger

tcmu: Add Type of reconfig into netlink

2017-07-07T06:11:32+00:00

This patch adds more info about the attribute being changed, so that usersapce can easily figure out what is happening. Signed-off-by: Bryant G. Ly Reviewed-By: Mike Christie Signed-off-by: Nicholas Bellinger