genlmsg_multicast_allns now returns the correct statuses when a message is
sent to a listener. However in the case of adding a device we want to wait
for the listener otherwise we may miss the the device during startup.
Signed-off-by: NCathy Avery <cavery@redhat.com>
Acked-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

This patch does not change any functionality but avoids that sparse
complains about the queue_cmd_ring() function and its callers.

Fixes: 6fd0ce79 ("tcmu: prep queue_cmd_ring to be used by unmap wq")
Reviewed-by: NDavid Disseldorp <ddiss@suse.de>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Cc: Mike Christie <mchristi@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

We use unsigned long, size_t and u64 for dev_size. This has us standardize
on u64.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Reviewed-by: NXiubo Li <xiubli@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Instead of doing strdup and kstrto* just use match_int for dev params.

It will be ok to use int instead of unsigned long in tcmu_set_dev_attrib
because that is only being used for max sectors and block size and the
supported values for them are well under the max possible integer value.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Reviewed-by: NXiubo Li <xiubli@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

This patch prevents a bug where data_bitmap is allocated in
tcmu_configure_device, userspace changes the max_blocks setting, the device
is mapped to a LUN, then we try to access the data_bitmap based on the new
max_blocks limit which may now be out of range.

To prevent this, we just check if data_bitmap has been setup. If it has
then we fail the max_blocks update operation.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Reviewed-by: NXiubo Li <xiubli@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

The tcmu dev is added to the list of tcmu devices during configuration.  At
this time the tcmu setup has completed, but lio core has not completed its
setup. The device is not yet usable so do not try to unmap blocks from it
Signed-off-by: NMike Christie <mchristi@redhat.com>
Reviewed-by: NXiubo Li <xiubli@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Do not allow userspace to block or reset the ring until the device has been
configured. This will prevent the bug where userspace can write to those
files and access mb_addr before it has been setup.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Reviewed-by: NXiubo Li <xiubli@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Use the lio core helper to check if the device is configured.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Reviewed-by: NXiubo Li <xiubli@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Use INIT_LIST_HEAD to initialize node list head.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Reviewed-by: NXiubo Li <xiubli@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

The caller of queue_cmd_ring grabs and releases the lock, so the
tcmu_setup_cmd_timer failure handling inside queue_cmd_ring should not call
mutex_unlock.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Reviewed-by: NXiubo Li <xiubli@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Fix warning:

smatch warnings:
drivers/target/target_core_user.c:301 tcmu_genl_cmd_done() warn: KERN_*
level not at start of string
Signed-off-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

This patch based on Xiubo's patches adds 2 tcmu attr to block and reset the
netlink interface. It's used during userspace daemon reinitialization after
the daemon has crashed while there is outstanding nl requests. The daemon
can block the nl interface, kill outstanding requests in the kernel and
then reopen the netlink socket and unblock it to allow new requests.

[mkp: typo]
Signed-off-by: NMike Christie <mchristi@redhat.com>
Tested-by: NXiubo Li <xiubli@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Some misc cleanup of the nl rework patches.

1. Fix space instead of tabs use and extra newline

2. Drop initializing variables to 0 when not needed

3. Just pass the skb_buff and msg_header pointers to
   tcmu_netlink_event_send.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Tested-by: NXiubo Li <xiubli@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Just return EBUSY if a nl request comes in while processing one. The upper
layers do not support sending multiple create/remove requests at the same
time (you cannot have a create and remove at the same time or do multiple
creates or removes at the same time) and doing a reconfig while a
create/remove is still executing does not make sense.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Tested-by: NXiubo Li <xiubli@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

The next patch is going to fix the hung nl command issue so this adds a
list of outstanding nl commands that we can later abort when the daemon is
restarted.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

When this code changed, this was never cleaned up.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Tested-by: NXiubo Li <xiubli@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Since the TCMU_RING_SIZE macro is not using here will discard it and at the
same time clean up the code style.
Signed-off-by: NXiubo Li <xiubli@redhat.com>
Acked-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

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: NBodo Stroesser <bstroesser@ts.fujitsu.com>
Acked-by: NMike Christie <mchristi@redhat.com>
Reviewed-by: NLee Duncan <lduncan@suse.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

The kzalloc() function has a 2-factor argument form, kcalloc(). This
patch replaces cases of:

        kzalloc(a * b, gfp)

with:
        kcalloc(a * b, gfp)

as well as handling cases of:

        kzalloc(a * b * c, gfp)

with:

        kzalloc(array3_size(a, b, c), gfp)

as it's slightly less ugly than:

        kzalloc_array(array_size(a, b), c, gfp)

This does, however, attempt to ignore constant size factors like:

        kzalloc(4 * 1024, gfp)

though any constants defined via macros get caught up in the conversion.

Any factors with a sizeof() of "unsigned char", "char", and "u8" were
dropped, since they're redundant.

The Coccinelle script used for this was:

// Fix redundant parens around sizeof().
@@
type TYPE;
expression THING, E;
@@

(
  kzalloc(
-	(sizeof(TYPE)) * E
+	sizeof(TYPE) * E
  , ...)
|
  kzalloc(
-	(sizeof(THING)) * E
+	sizeof(THING) * E
  , ...)
)

// Drop single-byte sizes and redundant parens.
@@
expression COUNT;
typedef u8;
typedef __u8;
@@

(
  kzalloc(
-	sizeof(u8) * (COUNT)
+	COUNT
  , ...)
|
  kzalloc(
-	sizeof(__u8) * (COUNT)
+	COUNT
  , ...)
|
  kzalloc(
-	sizeof(char) * (COUNT)
+	COUNT
  , ...)
|
  kzalloc(
-	sizeof(unsigned char) * (COUNT)
+	COUNT
  , ...)
|
  kzalloc(
-	sizeof(u8) * COUNT
+	COUNT
  , ...)
|
  kzalloc(
-	sizeof(__u8) * COUNT
+	COUNT
  , ...)
|
  kzalloc(
-	sizeof(char) * COUNT
+	COUNT
  , ...)
|
  kzalloc(
-	sizeof(unsigned char) * COUNT
+	COUNT
  , ...)
)

// 2-factor product with sizeof(type/expression) and identifier or constant.
@@
type TYPE;
expression THING;
identifier COUNT_ID;
constant COUNT_CONST;
@@

(
- kzalloc
+ kcalloc
  (
-	sizeof(TYPE) * (COUNT_ID)
+	COUNT_ID, sizeof(TYPE)
  , ...)
|
- kzalloc
+ kcalloc
  (
-	sizeof(TYPE) * COUNT_ID
+	COUNT_ID, sizeof(TYPE)
  , ...)
|
- kzalloc
+ kcalloc
  (
-	sizeof(TYPE) * (COUNT_CONST)
+	COUNT_CONST, sizeof(TYPE)
  , ...)
|
- kzalloc
+ kcalloc
  (
-	sizeof(TYPE) * COUNT_CONST
+	COUNT_CONST, sizeof(TYPE)
  , ...)
|
- kzalloc
+ kcalloc
  (
-	sizeof(THING) * (COUNT_ID)
+	COUNT_ID, sizeof(THING)
  , ...)
|
- kzalloc
+ kcalloc
  (
-	sizeof(THING) * COUNT_ID
+	COUNT_ID, sizeof(THING)
  , ...)
|
- kzalloc
+ kcalloc
  (
-	sizeof(THING) * (COUNT_CONST)
+	COUNT_CONST, sizeof(THING)
  , ...)
|
- kzalloc
+ kcalloc
  (
-	sizeof(THING) * COUNT_CONST
+	COUNT_CONST, sizeof(THING)
  , ...)
)

// 2-factor product, only identifiers.
@@
identifier SIZE, COUNT;
@@

- kzalloc
+ kcalloc
  (
-	SIZE * COUNT
+	COUNT, SIZE
  , ...)

// 3-factor product with 1 sizeof(type) or sizeof(expression), with
// redundant parens removed.
@@
expression THING;
identifier STRIDE, COUNT;
type TYPE;
@@

(
  kzalloc(
-	sizeof(TYPE) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kzalloc(
-	sizeof(TYPE) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kzalloc(
-	sizeof(TYPE) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kzalloc(
-	sizeof(TYPE) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kzalloc(
-	sizeof(THING) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kzalloc(
-	sizeof(THING) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kzalloc(
-	sizeof(THING) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kzalloc(
-	sizeof(THING) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
)

// 3-factor product with 2 sizeof(variable), with redundant parens removed.
@@
expression THING1, THING2;
identifier COUNT;
type TYPE1, TYPE2;
@@

(
  kzalloc(
-	sizeof(TYPE1) * sizeof(TYPE2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  kzalloc(
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  kzalloc(
-	sizeof(THING1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  kzalloc(
-	sizeof(THING1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  kzalloc(
-	sizeof(TYPE1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
|
  kzalloc(
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
)

// 3-factor product, only identifiers, with redundant parens removed.
@@
identifier STRIDE, SIZE, COUNT;
@@

(
  kzalloc(
-	(COUNT) * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kzalloc(
-	COUNT * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kzalloc(
-	COUNT * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kzalloc(
-	(COUNT) * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kzalloc(
-	COUNT * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kzalloc(
-	(COUNT) * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kzalloc(
-	(COUNT) * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kzalloc(
-	COUNT * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
)

// Any remaining multi-factor products, first at least 3-factor products,
// when they're not all constants...
@@
expression E1, E2, E3;
constant C1, C2, C3;
@@

(
  kzalloc(C1 * C2 * C3, ...)
|
  kzalloc(
-	(E1) * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
|
  kzalloc(
-	(E1) * (E2) * E3
+	array3_size(E1, E2, E3)
  , ...)
|
  kzalloc(
-	(E1) * (E2) * (E3)
+	array3_size(E1, E2, E3)
  , ...)
|
  kzalloc(
-	E1 * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
)

// And then all remaining 2 factors products when they're not all constants,
// keeping sizeof() as the second factor argument.
@@
expression THING, E1, E2;
type TYPE;
constant C1, C2, C3;
@@

(
  kzalloc(sizeof(THING) * C2, ...)
|
  kzalloc(sizeof(TYPE) * C2, ...)
|
  kzalloc(C1 * C2 * C3, ...)
|
  kzalloc(C1 * C2, ...)
|
- kzalloc
+ kcalloc
  (
-	sizeof(TYPE) * (E2)
+	E2, sizeof(TYPE)
  , ...)
|
- kzalloc
+ kcalloc
  (
-	sizeof(TYPE) * E2
+	E2, sizeof(TYPE)
  , ...)
|
- kzalloc
+ kcalloc
  (
-	sizeof(THING) * (E2)
+	E2, sizeof(THING)
  , ...)
|
- kzalloc
+ kcalloc
  (
-	sizeof(THING) * E2
+	E2, sizeof(THING)
  , ...)
|
- kzalloc
+ kcalloc
  (
-	(E1) * E2
+	E1, E2
  , ...)
|
- kzalloc
+ kcalloc
  (
-	(E1) * (E2)
+	E1, E2
  , ...)
|
- kzalloc
+ kcalloc
  (
-	E1 * E2
+	E1, E2
  , ...)
)
Signed-off-by: NKees Cook <keescook@chromium.org>

Problem:

$ cat /sys/kernel/config/target/core/user_0/block/attrib/qfull_time_out
-1

$ echo "-1" > /sys/kernel/config/target/core/user_0/block/attrib/qfull_time_out
-bash: echo: write error: Invalid argument

Fix:

This patch will help reset qfull_time_out to its default
i.e. qfull_time_out=-1.
Signed-off-by: NPrasanna Kumar Kalever <prasanna.kalever@redhat.com>
Acked-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

use new netlink events helpers tcmu_netlink_init() and
tcmu_netlink_send() to refactor netlink event attribute
TCMU_ATTR_WRITECACHE(belongs to TCMU_CMD_RECONFIG_DEVICE) which is also
emulate_write_cache in configFS.

Removed tcmu_netlink_event() since we have new netlink
events helpers now.
Signed-off-by: NZhu Lingshan <lszhu@suse.com>
Acked-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

use new netlink events helpers tcmu_netlink_init() and
tcmu_netlink_send() to refactor netlink event attribute
TCMU_ATTR_DEV_SIZE(belongs to TCMU_CMD_RECONFIG_DEVICE) which is also
dev_size in configFS.
Signed-off-by: NZhu Lingshan <lszhu@suse.com>
Acked-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

use new netlink events helpers tcmu_netlink_init() and
tcmu_netlink_send() to refactor netlink event attribute
TCMU_ATTR_DEV_CFG(belongs to TCMU_CMD_RECONFIG_DEVICE) which is also
dev_config in configFS.
Signed-off-by: NZhu Lingshan <lszhu@suse.com>
Acked-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

use new netlink events helpers tcmu_netlink_init() and
tcmu_netlink_send() to refactor netlink event TCMU_CMD_REMOVED_DEVICE
Signed-off-by: NZhu Lingshan <lszhu@suse.com>
Acked-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

use new netlink events helpers tcmu_netlink_init() and
tcmu_netlink_send() to refactor netlink event TCMU_CMD_ADDED_DEVICE
Signed-off-by: NZhu Lingshan <lszhu@suse.com>
Acked-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Add new netlink events helpers tcmu_netlink_event_init() and
tcmu_netlink_event_send(). These new functions intend to replace
existing netlink events helper function tcmu_netlink_event().

The existing function tcmu_netlink_event() works well for events like
TCMU_ADDED_DEVICE and TCMU_REMOVED_DEVICE which only has one netlink
attribute. But if there is a command requires more than one attributes
to send out, we have to use a struct to adapt the paremeter
reconfig_data, it is hard to use one struct or a union in one struct to
adapt every command with different attributes, it may get long and ugly.

With the new two functions, we can call tcmu_netlink_event_init() to
initialize a netlink event, then add all attributes we need by using
nla_put_xxx(), at last use tcmu_netlink_event_send() to send it out. So
that we don't need to use a long struct or union if we want to send
mulitple attributes for different commands.

[mkp: typos]
Signed-off-by: NZhu Lingshan <lszhu@suse.com>
Acked-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

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: NRandy Dunlap <rdunlap@infradead.org>
To: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
Cc: linux-scsi@vger.kernel.org
Cc: target-devel@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: "James E.J. Bottomley" <jejb@linux.vnet.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Use new return type vm_fault_t for fault handler in struct
vm_operations_struct.
Signed-off-by: NSouptick Joarder <jrdr.linux@gmail.com>
Reviewed-by: NMatthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

The trailing semicolon is an empty statement that does no operation.
It is completely stripped out by the compiler. Removing it since it doesn't do
anything.
Signed-off-by: NLuis de Bethencourt <luisbg@kernel.org>
Acked-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

If we are failing the command due to a qfull timeout we are
also freeing the tcmu command, so we cannot access it later
to get the se_cmd.

Note: The clearing of cmd->se_cmd is not needed. We do not check
it later for something like determining if the command was failed
due to a timeout. As a result I am dropping it.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch adds 2 tcmu attrs to block/unblock a device and
reset the ring buffer. They are used when the userspace
daemon has crashed or forced to shutdown while IO is executing.
On restart, the daemon can block the device so new IO is not
sent to userspace while it puts the ring in a clean state.

Notes: The reset ring opreation is specific to tcmu, but the
block one could be generic. I kept it tcmu specific, because
it requires some extra locking/state checks in the main IO
path and since other backend modules did not need this
functionality I thought only tcmu should take the perf hit.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Fix to return error code -ENOMEM from the kzalloc() error handling
case instead of 0, as done elsewhere in this function.

Fixes: 80eb8761 ("tcmu: allow max block and global max blocks to be settable")
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Acked-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Log cmd id that was not found in the tcmu_handle_completions
lookup failure path.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

We will always have a page mapped for cmd data if it is
valid command. If the mapping does not exist then something
bad happened in userspace and it should not proceed. This
has us return VM_FAULT_SIGBUS when this happens instead of
returning a freshly allocated paged. The latter can cause
corruption because userspace might write the pages data
overwriting valid data or return it to the initiator.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Users might have a physical system to a target so they could
have a lot more than 2 gigs of memory they want to devote to
tcmu. OTOH, we could be running in a vm and so a 2 gig
global and 1 gig per dev limit might be too high. This patch
allows the user to specify the limits.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This adds a timer, qfull_time_out, that controls how long a
device will wait for ring buffer space to open before
failing the commands in the queue. It is useful to separate
this timer from the cmd_time_out and default 30 sec one,
because for HA setups cmd_time_out may be disbled and 30
seconds is too long to wait when some OSs like ESX will
timeout commands after as little as 8 - 15 seconds.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch has tcmu internally queue cmds if its ring buffer
is full. It also makes the TCMU_GLOBAL_MAX_BLOCKS limit a
hint instead of a hard limit, so we do not have to add any
new locks/atomics in the main IO path except when IO is not
running.

This fixes the following bugs:

1. We cannot sleep from the submitting context because it might be
called from a target recv context. This results in transport level
commands timing out. For example if the ring is full, we would
sleep, and a iscsi initiator would send a iscsi ping/nop which
times out because the target's recv thread is sleeping here.

2. Devices were not fairly scheduled to run when they hit the global
limit so they could time out waiting for ring space while others
got run.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

We do not really save a lot by trying to increase thresh
a multiple of the existing value. This just simplifies the
code by increasing it to whatever is needed for the command
being executed.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

In the next patches we will call queue_cmd_ring from the submitting
context and also the completion path. This changes the queue_cmd_ring
return code so in the next patches we can return a sense_reason_t
and also signal if a command was requeued.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Add some comments to make the scatter code to be more readable,
and drop unused arg to new_iov.
Signed-off-by: NXiubo Li <lixiubo@cmss.chinamobile.com>
Signed-off-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>