Use generic io accounting functions to manage io stats. There was an
attempt to do this earlier in commit 18c0b223 ("md: use generic io
stats accounting functions to simplify io stat accounting"), but it did
not include a call to generic_end_io_acct() and caused issues with
tracking in-flight IOs, so it was later removed in commit 74672d06
("md: fix md io stats accounting broken").

This patch attempts to fix this by using both disk_start_io_acct() and
disk_end_io_acct(). To make it possible, a struct md_io is allocated for
every new md bio, which includes the io start_time. A new mempool is
introduced for this purpose. We override bio->bi_end_io with our own
callback and call disk_start_io_acct() before passing the bio to
md_handle_request(). When it completes, we call disk_end_io_acct() and
the original bi_end_io callback.

This adds correct statistics about in-flight IOs and IO processing time,
interpreted e.g. in iostat as await, svctm, aqu-sz and %util.

It also fixes a situation where too many IOs where reported if a bio was
re-submitted to the mddev, because io accounting is now performed only
on newly arriving bios.
Acked-by: NGuoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: NArtur Paszkiewicz <artur.paszkiewicz@intel.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>

Pointer mddev is being dereferenced with a test_bit call before mddev
is being null checked, this may cause a null pointer dereference. Fix
this by moving the null pointer checks to sanity check mddev before
it is dereferenced.

Addresses-Coverity: ("Dereference before null check")
Fixes: 62f7b198 ("md raid0/linear: Mark array as 'broken' and fail BIOs if a member is gone")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Reviewed-by: NGuilherme G. Piccoli <gpiccoli@canonical.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>

The wrappers in include/linux/pci-dma-compat.h should go away.

The patch has been generated with the coccinelle script bellow.
It has been compile tested.

This also aligns code with what is in use in '/rsxx/dma.c'

@@
@@
-    PCI_DMA_BIDIRECTIONAL
+    DMA_BIDIRECTIONAL

@@
@@
-    PCI_DMA_TODEVICE
+    DMA_TO_DEVICE

@@
@@
-    PCI_DMA_FROMDEVICE
+    DMA_FROM_DEVICE

@@
@@
-    PCI_DMA_NONE
+    DMA_NONE

@@
expression e1, e2, e3;
@@
-    pci_alloc_consistent(e1, e2, e3)
+    dma_alloc_coherent(&e1->dev, e2, e3, GFP_)

@@
expression e1, e2, e3;
@@
-    pci_zalloc_consistent(e1, e2, e3)
+    dma_alloc_coherent(&e1->dev, e2, e3, GFP_)

@@
expression e1, e2, e3, e4;
@@
-    pci_free_consistent(e1, e2, e3, e4)
+    dma_free_coherent(&e1->dev, e2, e3, e4)

@@
expression e1, e2, e3, e4;
@@
-    pci_map_single(e1, e2, e3, e4)
+    dma_map_single(&e1->dev, e2, e3, e4)

@@
expression e1, e2, e3, e4;
@@
-    pci_unmap_single(e1, e2, e3, e4)
+    dma_unmap_single(&e1->dev, e2, e3, e4)

@@
expression e1, e2, e3, e4, e5;
@@
-    pci_map_page(e1, e2, e3, e4, e5)
+    dma_map_page(&e1->dev, e2, e3, e4, e5)

@@
expression e1, e2, e3, e4;
@@
-    pci_unmap_page(e1, e2, e3, e4)
+    dma_unmap_page(&e1->dev, e2, e3, e4)

@@
expression e1, e2, e3, e4;
@@
-    pci_map_sg(e1, e2, e3, e4)
+    dma_map_sg(&e1->dev, e2, e3, e4)

@@
expression e1, e2, e3, e4;
@@
-    pci_unmap_sg(e1, e2, e3, e4)
+    dma_unmap_sg(&e1->dev, e2, e3, e4)

@@
expression e1, e2, e3, e4;
@@
-    pci_dma_sync_single_for_cpu(e1, e2, e3, e4)
+    dma_sync_single_for_cpu(&e1->dev, e2, e3, e4)

@@
expression e1, e2, e3, e4;
@@
-    pci_dma_sync_single_for_device(e1, e2, e3, e4)
+    dma_sync_single_for_device(&e1->dev, e2, e3, e4)

@@
expression e1, e2, e3, e4;
@@
-    pci_dma_sync_sg_for_cpu(e1, e2, e3, e4)
+    dma_sync_sg_for_cpu(&e1->dev, e2, e3, e4)

@@
expression e1, e2, e3, e4;
@@
-    pci_dma_sync_sg_for_device(e1, e2, e3, e4)
+    dma_sync_sg_for_device(&e1->dev, e2, e3, e4)

@@
expression e1, e2;
@@
-    pci_dma_mapping_error(e1, e2)
+    dma_mapping_error(&e1->dev, e2)

@@
expression e1, e2;
@@
-    pci_set_dma_mask(e1, e2)
+    dma_set_mask(&e1->dev, e2)

@@
expression e1, e2;
@@
-    pci_set_consistent_dma_mask(e1, e2)
+    dma_set_coherent_mask(&e1->dev, e2)
Signed-off-by: NChristophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

By the time a namespace is added to ctrl->namespaces list and thus
can be looked up ns->disk has been assigned, and it it never cleared.

Remove all the checks for ns->disk being NULL.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>

Signed-off-by: NBaolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The nvme_pci_iod_alloc_size() should return 'size_t' type to be
consistent with the sizeof return value.
Signed-off-by: NBaolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Add a blank line after declarations to make code more readable.
Signed-off-by: NBaolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Fix comment typos and remove whitespaces before tabs to cleanup
checkpatch errors.
Signed-off-by: NBaolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

We've validated the segment counts before calling nvme_map_data(),
so there is no need to validate again in nvme_pci_use_sgls(, which is
only called from nvme_map_data().
Signed-off-by: NBaolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Documented model names of Intel SSDs requiring quirks.
Signed-off-by: NDavid Fugate <david.fugate@linux.intel.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

This is useful information, and moreover its it's useful to
be able to alter these parameters per controller after it
has been established.
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Add support for NVM Express Zoned Namespaces (ZNS) Command Set defined
in NVM Express TP4053. Zoned namespaces are discovered based on their
Command Set Identifier reported in the namespaces Namespace
Identification Descriptor list. A successfully discovered Zoned
Namespace will be registered with the block layer as a host managed
zoned block device with Zone Append command support. A namespace that
does not support append is not supported by the driver.
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NJavier González <javier.gonz@samsung.com>
Reviewed-by: NHimanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: NHans Holmberg <hans.holmberg@wdc.com>
Signed-off-by: NDmitry Fomichev <dmitry.fomichev@wdc.com>
Signed-off-by: NAjay Joshi <ajay.joshi@wdc.com>
Signed-off-by: NAravind Ramesh <aravind.ramesh@wdc.com>
Signed-off-by: NNiklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: NMatias Bjørling <matias.bjorling@wdc.com>
Signed-off-by: NDamien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: NKeith Busch <keith.busch@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The Commands Supported and Effects log page was extended with a CSI
field that enables the host to query the log page for each command set
supported. Retrieve this log page for each command set that an attached
namespace supports, and save a pointer to that log in the namespace head.
Reviewed-by: NMatias Bjørling <matias.bjorling@wdc.com>
Reviewed-by: NJavier González <javier.gonz@samsung.com>
Reviewed-by: NHimanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: NDaniel Wagner <dwagner@suse.de>
Signed-off-by: NKeith Busch <keith.busch@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Implements support for multiple I/O Command Sets.  NVMe TP 4056
introduces a method to enumerate multiple command sets per namespace. If
the command set is exposed, this method for enumeration will be used
instead of the traditional method that uses the CC.CSS register command
set register for command set identification.

For namespaces where the Command Set Identifier is not supported or
recognized, the specific namespace will not be created.
Reviewed-by: NJavier González <javier.gonz@samsung.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: NMatias Bjørling <matias.bjorling@wdc.com>
Reviewed-by: NDaniel Wagner <dwagner@suse.de>
Reviewed-by: NHimanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NNiklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Allow emulation of a zoned device with a per zone capacity smaller than
the zone size as as defined in the Zoned Namespace (ZNS) Command Set
specification. The zone capacity defaults to the zone size if not
specified and must be smaller than the zone size otherwise.
Reviewed-by: NMatias Bjørling <matias.bjorling@wdc.com>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NHimanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: NDaniel Wagner <dwagner@suse.de>
Signed-off-by: NAravind Ramesh <aravind.ramesh@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

In the zoned storage model, the sectors within a zone are typically all
writeable. With the introduction of the Zoned Namespace (ZNS) Command
Set in the NVM Express organization, the model was extended to have a
specific writeable capacity.

Extend the zone descriptor data structure with a zone capacity field to
indicate to the user how many sectors in a zone are writeable.

Introduce backward compatibility in the zone report ioctl by extending
the zone report header data structure with a flags field to indicate if
the capacity field is available.
Reviewed-by: NJens Axboe <axboe@kernel.dk>
Reviewed-by: NJavier González <javier.gonz@samsung.com>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NHimanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: NDaniel Wagner <dwagner@suse.de>
Signed-off-by: NMatias Bjørling <matias.bjorling@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Use USEC_PER_SEC instead of magic numbers to make code more readable.
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NBaolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

We can make it shorter and simpler without some redundant checks.
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

If we have a long list of request to send, signal the network stack
that more is coming (MSG_MORE). If we have nothing else, signal MSG_EOR.
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Tested-by: NMark Wunderlich <mark.wunderlich@intel.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

blk-mq request plugging can improve the execution of our pipeline.
When we queue a request we actually trigger our I/O worker thread
yielding a context switch by definition. However if we know that
there are more requests in the pipe that are coming, we are better
off not trigger our I/O worker and only do that for the last request
in the batch (bd->last). By having it, we improve efficiency by
amortizing context switches over a batch of requests.
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Tested-by: NMark Wunderlich <mark.wunderlich@intel.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The queue processing will splice to a queue local list, this should
alleviate some contention on the send_list lock, but also prepares
us to the next patch where we look on these lists for network stack
flag optimization.

Remove queue lock as its not used anymore.
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Tested-by: NMark Wunderlich <mark.wunderlich@intel.com>
[hch: simplified a loop]
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The nvme host and target verify the wwnn and wwpn format via
nvme_fc_parse_traddr(). For instance, it is required that the length of
wwnn to be either 21 ("nn-0x") or 19 (nn-).

Add this verification to nvme-fcloop so that the input should always be in
hex and the length of input should always be 18.

Otherwise, the user may use e.g. 0x2 to create fcloop local port, while
0x0000000000000002 is required for nvme host and target. This makes the
requirement of format confusing.
Signed-off-by: NDongli Zhang <dongli.zhang@oracle.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NJames Smart <james.smart@broadcom.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

In function nvmet_subsys_atte_version_show() which uses the NVME_XXX()
macros related to version (of type u64) get rid of the int type cast
when printing subsys version and use appropriate format specifier for
u64.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Replace has_keyed_sgls and metadata_support booleans with a flags member
that will be used for adding more features in the future.
Signed-off-by: NMax Gurtovoy <maxg@mellanox.com>
Reviewed-by: NHimanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: NIsrael Rukshin <israelr@mellanox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Since the nvmet_tcp_ops is static, there is no need to initialize values
to zero.
Signed-off-by: NMax Gurtovoy <maxg@mellanox.com>
Reviewed-by: NIsrael Rukshin <israelr@mellanox.com>
Reviewed-by: NHimanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

This field is never used since the introduction of nvme loopback by
commit 3a85a5de ("nvme-loop: add a NVMe loopback host driver").
Signed-off-by: NDongli Zhang <dongli.zhang@oracle.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Just cleanup by removing the empty line.
Signed-off-by: NDongli Zhang <dongli.zhang@oracle.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Although use of for loop is preferred it is not a common practice to
have 80 char long for loop initialization and comparison section.

Use temp variables for calculating values and replace them in the
for loop with size of all variables to set to u64 since preferred
variable is declared as u64.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The NVMe PCIe declares module parameter io_queue_depth as int. Change
this to u16 as queue depth can never be negative. Now to reflect this
update module parameter getter function from param_get_int() ->
param_get_uint() and respective setter function with type of n changed
from int to u16 with param_set_int() to param_set_ushort(). Finally
update struct nvme_dev q_depth member to u16 and use u16 in min_t()
when calculating dev->q_depth in the nvme_pci_enable() (since q_depth is
now u16) and use unsigned int instead of int when calculating
dev->tagset.queue_depth as target variable tagset->queue_depth is of type
unsigned int in nvme_dev_add().
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

In nvme_init_identify() when calculating submission queue size use u16
instead of int type in the min_t() since target variable ctrl->sqsize is
of type u16.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

In nvme_configure_directives() when calculating number of streams use
u16 instead of unsigned type in the min_t() since target variable
ctrl->nr_streams is of type u16.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

I2C_SMBUS_BLOCK_MAX defines already the maximum number as defined in the
SMBus 2.0 specs. I don't see a reason to add 1 here. Also, fix the errno
to what is suggested for this error.

Fixes: c9bfdc7c ("i2c: mlxcpld: Add support for smbus block read transaction")
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: NMichael Shych <michaelsh@mellanox.com>
Tested-by: NMichael Shych <michaelsh@mellanox.com>
Signed-off-by: NWolfram Sang <wsa@kernel.org>

I can't recall why there was none, but we surely want to have it.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: NNiklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NWolfram Sang <wsa@kernel.org>

Add more details which have either been missing ever since or describe
recent additions.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: NNiklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: NLuca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: NWolfram Sang <wsa@kernel.org>

The driver can't be loaded automatically because it misses
module alias to be provided. Add corresponding MODULE_DEVICE_TABLE()
call to the driver.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NWolfram Sang <wsa@kernel.org>

Current AMD's zen-based APUs use this core for some of its i2c-buses.

With this patch we re-enable autodetection of hwmon-alike devices, so
lm-sensors will be able to work automatically.

It does not affect the boot-time of embedded devices, as the class is
set based on the DMI information.

DMI is probed only on Qtechnology QT5222 Industrial Camera Platform.

DocLink: https://qtec.com/camera-technology-camera-platforms/
Fixes: 3eddad96 ("i2c: designware: reverts "i2c: designware: Add support for AMD I2C controller"")
Signed-off-by: NRicardo Ribalda <ribalda@kernel.org>
Reviewed-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: NJarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: NWolfram Sang <wsa@kernel.org>

The PCA9665 datasheet says that I2CSTA = 78h indicates that SCL is stuck
low, this differs to the PCA9564 which uses 90h for this indication.
Treat either 0x78 or 0x90 as an indication that the SCL line is stuck.

Based on looking through the PCA9564 and PCA9665 datasheets this should
be safe for both chips. The PCA9564 should not return 0x78 for any valid
state and the PCA9665 should not return 0x90.

Fixes: eff9ec95 ("i2c-algo-pca: Add PCA9665 support")
Signed-off-by: NChris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NWolfram Sang <wsa@kernel.org>

Fix a typo in SENSORS_IR35221 option: module name should be "ir35221"
instead of "ir35521".

Fixes: 8991ebd9 ("hwmon: (pmbus) Add client driver for IR35221")

Cc: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: NTao Ren <rentao.bupt@gmail.com>
Link: https://lore.kernel.org/r/20200702221349.18139-1-rentao.bupt@gmail.comSigned-off-by: NGuenter Roeck <linux@roeck-us.net>

Today xenbus_map_ring_valloc() can return either a negative errno
value (-ENOMEM or -EINVAL) or a grant status value. This is a mess as
e.g -ENOMEM and GNTST_eagain have the same numeric value.

Fix that by turning all grant mapping errors into -ENOENT. This is
no problem as all callers of xenbus_map_ring_valloc() only use the
return value to print an error message, and in case of mapping errors
the grant status value has already been printed by __xenbus_map_ring()
before.
Signed-off-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20200701121638.19840-3-jgross@suse.comSigned-off-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>

xenbus_map_ring_valloc() and its sub-functions are putting quite large
structs and arrays on the stack. This is problematic at runtime, but
might also result in build failures (e.g. with clang due to the option
-Werror,-Wframe-larger-than=... used).

Fix that by moving most of the data from the stack into a dynamically
allocated struct. Performance is no issue here, as
xenbus_map_ring_valloc() is used only when adding a new PV device to
a backend driver.

While at it move some duplicated code from pv/hvm specific mapping
functions to the single caller.
Reported-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20200701121638.19840-2-jgross@suse.comSigned-off-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>