linux.git/drivers/target/target_core_user.c, branch v5.17

scsi: target: tcmu: Allocate zeroed pages for data area

2021-10-19T02:38:35+00:00

Tcmu populates the data area (used for communication with userspace) with
pages that are allocated by calling alloc_page(GFP_NOIO).  Therefore
previous content of the allocated pages is exposed to user space. Avoid
this by adding __GFP_ZERO flag.

Zeroing the pages does (nearly) not affect tcmu throughput, because
allocated pages are re-used for the data transfers of later SCSI cmds.

Link: https://lore.kernel.org/r/20211013171606.25197-1-bostroesser@gmail.com
Signed-off-by: Bodo Stroesser 
Signed-off-by: Martin K. Petersen

scsi: target: tcmu: Use struct_size() helper in kmalloc()

2021-10-05T03:29:38+00:00

Make use of the struct_size() helper instead of an open-coded version, in
order to avoid any potential type mistakes or integer overflows that, in
the worst scenario, could lead to heap overflows.

Link: https://github.com/KSPP/linux/issues/160
Link: https://lore.kernel.org/r/20210927224344.GA190701@embeddedor
Reviewed-by: Bodo Stroesser 
Signed-off-by: Gustavo A. R. Silva 
Signed-off-by: Martin K. Petersen

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

Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

2021-07-02T22:14:36+00:00

Pull SCSI updates from James Bottomley:
 "This series consists of the usual driver updates (ufs, ibmvfc,
  megaraid_sas, lpfc, elx, mpi3mr, qedi, iscsi, storvsc, mpt3sas) with
  elx and mpi3mr being new drivers.

  The major core change is a rework to drop the status byte handling
  macros and the old bit shifted definitions and the rest of the updates
  are minor fixes"

* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (287 commits)
  scsi: aha1740: Avoid over-read of sense buffer
  scsi: arcmsr: Avoid over-read of sense buffer
  scsi: ips: Avoid over-read of sense buffer
  scsi: ufs: ufs-mediatek: Add missing of_node_put() in ufs_mtk_probe()
  scsi: elx: libefc: Fix IRQ restore in efc_domain_dispatch_frame()
  scsi: elx: libefc: Fix less than zero comparison of a unsigned int
  scsi: elx: efct: Fix pointer error checking in debugfs init
  scsi: elx: efct: Fix is_originator return code type
  scsi: elx: efct: Fix link error for _bad_cmpxchg
  scsi: elx: efct: Eliminate unnecessary boolean check in efct_hw_command_cancel()
  scsi: elx: efct: Do not use id uninitialized in efct_lio_setup_session()
  scsi: elx: efct: Fix error handling in efct_hw_init()
  scsi: elx: efct: Remove redundant initialization of variable lun
  scsi: elx: efct: Fix spelling mistake "Unexected" -> "Unexpected"
  scsi: lpfc: Fix build error in lpfc_scsi.c
  scsi: target: iscsi: Remove redundant continue statement
  scsi: qla4xxx: Remove redundant continue statement
  scsi: ppa: Switch to use module_parport_driver()
  scsi: imm: Switch to use module_parport_driver()
  scsi: mpt3sas: Fix error return value in _scsih_expander_add()
  ...

scsi: target: tcmu: Fix boolreturn.cocci warnings

2021-05-21T21:14:21+00:00

drivers/target/target_core_user.c:1424:9-10: WARNING: return of 0/1 in function 'tcmu_handle_completions' with return type bool

 Return statements in functions returning bool should use
 true/false instead of 1/0.

Generated by: scripts/coccinelle/misc/boolreturn.cocci

Link: https://lore.kernel.org/r/20210515230358.GA97544@60d1edce16e0
Fixes: 9814b55cde05 ("scsi: target: tcmu: Return from tcmu_handle_completions() if cmd_id not found")
CC: Bodo Stroesser 
Reported-by: kernel test robot 
Acked-by: Bodo Stroesser 
Signed-off-by: kernel test robot 
Signed-off-by: Martin K. Petersen

scsi: target: tcmu: Fix xarray RCU warning

2021-05-21T20:15:48+00:00

Commit f5ce815f34bc ("scsi: target: tcmu: Support DATA_BLOCK_SIZE = N *
PAGE_SIZE") introduced xas_next() calls to iterate xarray elements.  These
calls triggered the WARNING "suspicious RCU usage" at tcmu device set up
[1]. In the call stack of xas_next(), xas_load() was called.  According to
its comment, this function requires "the xa_lock or the RCU lock".

To avoid the warning:

 - Guard the small loop calling xas_next() in tcmu_get_empty_block with RCU
   lock.

 - In the large loop in tcmu_copy_data using RCU lock would possibly
   disable preemtion for a long time (copy multi MBs). Therefore replace
   XA_STATE, xas_set and xas_next with a single xa_load.

[1]

[ 1899.867091] =============================
[ 1899.871199] WARNING: suspicious RCU usage
[ 1899.875310] 5.13.0-rc1+ #41 Not tainted
[ 1899.879222] -----------------------------
[ 1899.883299] include/linux/xarray.h:1182 suspicious rcu_dereference_check() usage!
[ 1899.890940] other info that might help us debug this:
[ 1899.899082] rcu_scheduler_active = 2, debug_locks = 1
[ 1899.905719] 3 locks held by kworker/0:1/1368:
[ 1899.910161]  #0: ffffa1f8c8b98738 ((wq_completion)target_submission){+.+.}-{0:0}, at: process_one_work+0x1ee/0x580
[ 1899.920732]  #1: ffffbd7040cd7e78 ((work_completion)(&q->sq.work)){+.+.}-{0:0}, at: process_one_work+0x1ee/0x580
[ 1899.931146]  #2: ffffa1f8d1c99768 (&udev->cmdr_lock){+.+.}-{3:3}, at: tcmu_queue_cmd+0xea/0x160 [target_core_user]
[ 1899.941678] stack backtrace:
[ 1899.946093] CPU: 0 PID: 1368 Comm: kworker/0:1 Not tainted 5.13.0-rc1+ #41
[ 1899.953070] Hardware name: System manufacturer System Product Name/PRIME Z270-A, BIOS 1302 03/15/2018
[ 1899.962459] Workqueue: target_submission target_queued_submit_work [target_core_mod]
[ 1899.970337] Call Trace:
[ 1899.972839]  dump_stack+0x6d/0x89
[ 1899.976222]  xas_descend+0x10e/0x120
[ 1899.979875]  xas_load+0x39/0x50
[ 1899.983077]  tcmu_get_empty_blocks+0x115/0x1c0 [target_core_user]
[ 1899.989318]  queue_cmd_ring+0x1da/0x630 [target_core_user]
[ 1899.994897]  ? rcu_read_lock_sched_held+0x3f/0x70
[ 1899.999695]  ? trace_kmalloc+0xa6/0xd0
[ 1900.003501]  ? __kmalloc+0x205/0x380
[ 1900.007167]  tcmu_queue_cmd+0x12f/0x160 [target_core_user]
[ 1900.012746]  __target_execute_cmd+0x23/0xa0 [target_core_mod]
[ 1900.018589]  transport_generic_new_cmd+0x1f3/0x370 [target_core_mod]
[ 1900.025046]  transport_handle_cdb_direct+0x34/0x50 [target_core_mod]
[ 1900.031517]  target_queued_submit_work+0x43/0xe0 [target_core_mod]
[ 1900.037837]  process_one_work+0x268/0x580
[ 1900.041952]  ? process_one_work+0x580/0x580
[ 1900.046195]  worker_thread+0x55/0x3b0
[ 1900.049921]  ? process_one_work+0x580/0x580
[ 1900.054192]  kthread+0x143/0x160
[ 1900.057499]  ? kthread_create_worker_on_cpu+0x40/0x40
[ 1900.062661]  ret_from_fork+0x1f/0x30

Link: https://lore.kernel.org/r/20210519135440.26773-1-bostroesser@gmail.com
Fixes: f5ce815f34bc ("scsi: target: tcmu: Support DATA_BLOCK_SIZE = N * PAGE_SIZE")
Reported-by: Shin'ichiro Kawasaki 
Tested-by: Shin'ichiro Kawasaki 
Signed-off-by: Bodo Stroesser 
Signed-off-by: Martin K. Petersen

scsi: target: tcmu: Rename TCM_DEV_BIT_PLUGGED to TCMU_DEV_BIT_PLUGGED

2021-05-15T02:58:27+00:00

The bit definition TCM_DEV_BIT_PLUGGED should correctly be named
TCMU_DEV_BIT_PLUGGED, since all other bits in the same bitfield have prefix
TCMU_.

Link: https://lore.kernel.org/r/20210512140654.31249-1-bostroesser@gmail.com
Signed-off-by: Bodo Stroesser 
Signed-off-by: Martin K. Petersen

scsi: target: tcmu: Return from tcmu_handle_completions() if cmd_id not found

2021-04-29T02:55:00+00:00

If tcmu_handle_completions() finds an invalid cmd_id while looping over cmd
responses from userspace it sets TCMU_DEV_BIT_BROKEN and breaks the
loop. This means that it does further handling for the tcmu device.

Skip that handling by replacing 'break' with 'return'.

Additionally change tcmu_handle_completions() from unsigned int to bool,
since the value used in return already is bool.

Link: https://lore.kernel.org/r/20210423150123.24468-1-bostroesser@gmail.com
Signed-off-by: Bodo Stroesser 
Signed-off-by: Martin K. Petersen

scsi: target: tcmu: Make data_pages_per_blk changeable via configfs

2021-04-13T02:40:56+00:00

Make data_pages_per_blk changeable similar to the way it is done for
max_data_area_mb. One can change the value by typing:

  echo "data_pages_per_blk=N" >control

The value is printed when doing:

  cat info

In addition, a new readonly attribute 'data_pages_per_blk' returns the
value on read.

Link: https://lore.kernel.org/r/20210324195758.2021-7-bostroesser@gmail.com
Signed-off-by: Bodo Stroesser 
Signed-off-by: Martin K. Petersen

scsi: target: tcmu: Replace block size definitions with new udev members

2021-04-13T02:40:56+00:00

Replace DATA_PAGES_PER_BLK and DATA_BLOCK_SIZE with new struct elements
tcmu_dev->data_pages_per_blk and tcmu_dev->data_blk_size.  These new
variables are still loaded with constant definition DATA_PAGES_PER_BLK_DEF
(= 1) and DATA_PAGES_PER_BLK_DEF * PAGE_SIZE.

There is no way yet to set the values via configfs.

Link: https://lore.kernel.org/r/20210324195758.2021-6-bostroesser@gmail.com
Signed-off-by: Bodo Stroesser 
Signed-off-by: Martin K. Petersen